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CN116889119A - Light emitting device, light emitting apparatus, electronic apparatus, display apparatus, and lighting apparatus - Google Patents

Light emitting device, light emitting apparatus, electronic apparatus, display apparatus, and lighting apparatus Download PDF

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Publication number
CN116889119A
CN116889119A CN202280011221.1A CN202280011221A CN116889119A CN 116889119 A CN116889119 A CN 116889119A CN 202280011221 A CN202280011221 A CN 202280011221A CN 116889119 A CN116889119 A CN 116889119A
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Prior art keywords
layer
emitting device
light
light emitting
electrode
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CN202280011221.1A
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Inventor
大泽信晴
濑尾哲史
吉安唯
吉住英子
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Semiconductor Energy Laboratory Co Ltd
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Semiconductor Energy Laboratory Co Ltd
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Priority claimed from PCT/IB2022/050498 external-priority patent/WO2022162508A1/en
Publication of CN116889119A publication Critical patent/CN116889119A/en
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Abstract

Provided is a novel light emitting device excellent in convenience, practicality, or reliability. The light emitting device includes a first electrode, a second electrode, and a first layer between the first electrode and the second electrode, the first layer including a light emitting material, a first organic compound, and a first material. The luminescent material has a function of emitting fluorescence, the luminescent material having an end located at the longest wavelength of the absorption spectrum at the first wavelength. The first organic compound has a function of converting triplet excitation energy into luminescence having an end portion located at the shortest wavelength of the spectrum at a second wavelength, which is located at a short wavelength compared to the first wavelength. In addition, the first organic compound includes a first substituent R1, and the first substituent R1 is any one of an alkyl group, a cycloalkyl group, and a trialkylsilyl group. In addition, the first material has a function of emitting delayed fluorescence at room temperature, and a difference between a HOMO level and a LUMO level of the first material is smaller than a difference between a HOMO level and a LUMO level of the first organic compound.

Description

Light emitting device, light emitting apparatus, electronic apparatus, display apparatus, and lighting apparatus
Technical Field
One embodiment of the present invention relates to a light emitting device, a light emitting apparatus, an electronic apparatus, a display apparatus, a lighting apparatus, or a semiconductor apparatus.
Note that one embodiment of the present invention is not limited to the above-described technical field. The technical field of one embodiment of the invention disclosed in the present specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, a product, or a composition (composition of matter). More specifically, examples of the technical field of one embodiment of the present invention disclosed in the present specification include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, a driving method of these devices, and a manufacturing method of these devices.
Background
In recent years, research and development of light emitting devices using Electroluminescence (EL) have been increasingly underway. The basic structure of these light-emitting devices is a structure in which a layer containing a light-emitting substance (EL layer) is sandwiched between a pair of electrodes. By applying a voltage between electrodes of the light-emitting device, light emission from the light-emitting substance can be obtained.
Since the above-described light emitting device is a self-luminous light emitting device, a display apparatus using the light emitting device has the following advantages: the method has good visibility; no backlight is required; and low power consumption, etc. In addition, the method has the following advantages: can be made thin and light; and a fast response speed, etc.
When a light-emitting device (for example, an organic EL element) is used in which an organic compound is used as a light-emitting substance and an EL layer containing the light-emitting substance is provided between a pair of electrodes, a voltage is applied between the pair of electrodes, and electrons and holes are injected from a cathode and an anode, respectively, to the light-emitting EL layer, whereby a current flows. The injected electrons and holes are recombined to bring the light-emitting organic compound into an excited state, whereby light emission can be obtained from the excited light-emitting organic compound.
As the kind of the excited state formed by the organic compound, there is a singlet excited state (S ＊ ) Triplet excited state (T) ＊ ) Luminescence from a singlet excited state is referred to as fluorescence, and luminescence from a triplet excited state is referred to as phosphorescence. In addition, in the light-emitting device, the statistically generated ratio of the singlet excited state and the triplet excited state is considered to be S ＊ ：T ＊ =1: 3. therefore, the light-emitting device using the compound that emits phosphorescence (phosphorescent material) has higher light-emitting efficiency than the light-emitting device using the compound that emits fluorescence (fluorescent material). Accordingly, in recent years, research and development of light emitting devices using a phosphorescent material capable of converting triplet excitation energy into luminescence have been increasingly underway.
Among light emitting devices using phosphorescent materials, particularly light emitting devices emitting blue light have not been put into practical use because it is difficult to develop stable compounds having high triplet excitation levels. Accordingly, development of a light emitting device using a more stable fluorescent material is being conducted, and a method of improving the light emitting efficiency of a light emitting device using a fluorescent material (fluorescent light emitting device) is being sought.
As a material capable of converting part or all of triplet excitation energy into luminescence, a thermally activated delayed fluorescence (TADF: thermally Activated Delayed Fluorescence) material is known in addition to a phosphorescent material. In the thermally activated delayed fluorescent material, a singlet excited state is generated from a triplet excited state by intersystem crossing, and energy of the singlet excited state is converted into luminescence.
In order to improve the light emission efficiency in a light emitting device using a thermally activated delayed fluorescence material, it is important that not only a singlet excited state is efficiently generated from a triplet excited state in the thermally activated delayed fluorescence material, but also light emission is efficiently obtained from the singlet excited state, that is, that the fluorescence quantum yield is high. However, it is difficult to design a light emitting material that satisfies both of the above conditions.
Furthermore, the following methods have been proposed: in a light-emitting device including a thermally activated delayed fluorescent material and a fluorescent material, the single excitation energy of the thermally activated delayed fluorescent material is transferred to the fluorescent material, and light emission is obtained from the fluorescent material (see patent document 1).
In addition, a light-emitting device including a host material and a guest material in a light-emitting layer is known (see patent document 2). The host material has a function of converting triplet excitation energy into luminescence, and the guest material emits fluorescence. The guest material has a molecular structure containing a light-emitting body and a protecting group, and one guest material molecule contains five or more protecting groups. By including a protective group in the molecule, transfer of triplet excitation energy from the host material to the guest material based on the texel mechanism can be suppressed. As the protecting group, an alkyl group or a branched alkyl group can be used.
[ Prior Art literature ]
[ patent literature ]
[ patent document 1] Japanese patent application laid-open No. 2014-45179
Patent document 2 international patent application publication No. 2019/171197 pamphlet
Disclosure of Invention
Technical problem to be solved by the invention
It is an object of one embodiment of the present invention to provide a novel light emitting device excellent in convenience, practicality, or reliability. Further, an object of one embodiment of the present invention is to provide a novel electronic device excellent in convenience, practicality, or reliability. Further, an object of one embodiment of the present invention is to provide a novel display device excellent in convenience, practicality, or reliability. Further, an object of one embodiment of the present invention is to provide a novel lighting device excellent in convenience, practicality, or reliability. Further, it is an object of one embodiment of the present invention to provide a novel light emitting device, a novel light emitting apparatus, a novel electronic device, a novel display apparatus, a novel lighting apparatus, or a novel semiconductor apparatus.
Note that the description of these objects does not hinder the existence of other objects. Note that one embodiment of the present invention is not required to achieve all of the above objects. Further, the objects other than the above objects are apparent from the descriptions of the specification, drawings, claims, and the like, and the objects other than the above objects can be extracted from the descriptions of the specification, drawings, claims, and the like.
Means for solving the technical problems
(1) One embodiment of the present invention is a light-emitting device including a first electrode, a second electrode, and a first layer.
The second electrode includes a region overlapping the first electrode, and a first layer is located between the first electrode and the second electrode, the first layer including a light emitting material FM, a first organic compound, and a first material.
The luminescent material FM has a function of emitting fluorescence, the luminescent material FM having an end located at the longest wavelength of the absorption spectrum at a first wavelength λabs (nm).
The first organic compound has a function of converting triplet excitation energy into luminescence, and the luminescence of the first organic compound has an end portion located at the shortest wavelength of the spectrum at a second wavelength λp (nm) located at a short wavelength compared to the first wavelength λabs.
In addition, the first organic compound includes a first substituent R 1 A first substituent R 1 Is any of alkyl, substituted or unsubstituted cycloalkyl, and trialkylsilyl. Note that the number of carbon atoms of the alkyl group is 3 or more and 12 or less, the number of ring-forming carbon atoms of the cycloalkyl group is 3 or more and 10 or less, and the number of carbon atoms of the trialkylsilyl group is 3 or more and 12 or less.
In addition, the first material has a function of emitting delayed fluorescence at room temperature.
(2) In addition, one embodiment of the present invention is a light-emitting device including a first electrode, a second electrode, and a first layer.
The second electrode includes a region overlapping the first electrode, and a first layer is located between the first electrode and the second electrode, the first layer including a light emitting material FM, a first organic compound, and a first material.
The luminescent material FM has a function of emitting fluorescence, the luminescent material FM having an end located at the longest wavelength of the absorption spectrum at a first wavelength λabs (nm).
The first organic compound has a function of converting triplet excitation energy into luminescence, and the luminescence of the first organic compound has an end portion located at the shortest wavelength of the spectrum at a second wavelength λp (nm) located at a short wavelength compared to the first wavelength λabs.
In addition, the first organic compound includes a first substituent R 1 A first substituent R 1 Is any of substituted or unsubstituted alkyl, cycloalkyl, and trialkylsilyl groups. The alkyl group has 3 to 12 carbon atoms, the cycloalkyl group has 3 to 10 ring-forming carbon atoms, and the trialkylsilyl group has 3 to 12 carbon atoms.
The first material is composed of a second organic compound and a third organic compound, the second organic compound and the third organic compound forming an exciplex.
(3) In addition, in the light-emitting device according to an embodiment of the present invention, the first organic compound has a first HOMO level HOMO1 and a first LUMO level LUMO1, and the first material has a second HOMO level HOMO2 and a second LUMO level LUMO2.
The first HOMO level HOMO1, the first LUMO level LUMO1, the second HOMO level HOMO2, and the second LUMO level LUMO2 satisfy the following expression (1).
[ formula 1]
(LUMO2-HOMO2)＜(LUMO1-HOMO1)···(1)
Thus, the first organic compound can be used as the energy donor material ED and the energy of the energy donor material ED, especially the energy of the triplet excited stateThe amount is transferred to the luminescent material FM. In addition, the energy donor material ED and the adjacent luminescent material FM are clamped with a first substituent R 1 . In addition, the distance between the centers of the energy donor material ED and the adjacent luminescent material FM may be made suitable. In addition, energy transfer based on the tex mechanism can be suppressed. In addition, energy transfer based on the foster mechanism can be dominant. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved.
In addition, triplet excitons generated by the first material may be converted to singlet excitons. In addition, carriers transferred in the first material may be increased by making a difference between the HOMO level and the LUMO level derived from the first material smaller than a difference between the HOMO level and the LUMO level derived from the first organic compound. In addition, the recombination probability of carriers in the first material can be improved. In addition, energy may be transferred from excitons generated by the first material to the energy donor material ED. In addition, excitons may be generated in the first material and the energy of the excitons is transferred to the light emitting material FM through the energy donor material ED. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
Thereby, carriers transferred in the first material can be increased. In addition, the recombination probability of carriers in the first material can be improved. In addition, energy may be transferred from excitons generated by the first material to the energy donor material ED. In addition, excitons may be generated in the first material and the energy of the excitons is transferred to the light emitting material FM through the energy donor material ED. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
(4) In addition, one of the present inventionIn such a way that the light emitting device described above, the luminescent material FM comprises a second substituent R 2 A second substituent R 2 Is any one of methyl, alkyl having a branched chain, substituted or unsubstituted cycloalkyl and trialkylsilyl.
Note that the branched alkyl group has 3 to 12 carbon atoms, the cyclic carbon atom of the cycloalkyl group has 3 to 10 carbon atoms, and the trialkylsilyl group has 3 to 12 carbon atoms.
(5) In addition, one embodiment of the present invention is the light-emitting device, wherein the light-emitting material FM includes five or more second substituents R 2 More than five second substituents R 2 At least five second substituents R 2 Each independently is any of alkyl having a branch, substituted or unsubstituted cycloalkyl, and trialkylsilyl.
Note that the branched alkyl group has 3 to 12 carbon atoms, the cyclic carbon atom of the cycloalkyl group has 3 to 10 carbon atoms, and the trialkylsilyl group has 3 to 12 carbon atoms.
Whereby the luminescent material FM is sandwiched with the adjacent energy donor material ED by a second substituent R 2 . In addition, the distance between the centers of the energy donor material ED and the adjacent luminescent material FM may be made suitable. In addition, energy transfer based on the tex mechanism can be suppressed. In addition, energy transfer based on the foster mechanism can be dominant. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
(6) In addition, an embodiment of the present invention is the light emitting device described above, wherein the light emitting material FM has a third LUMO level LUMO3, and the third LUMO level LUMO3 is higher than the second LUMO level LUMO 2.
(7) In addition, in the light emitting device according to the present invention, the second HOMO level HOMO2 is higher than the first HOMO level HOMO1, and the second LUMO level LUMO2 is lower than the first LUMO level LUMO 1.
Thereby, electrons can be suppressed from being trapped in the luminescent material FM. In addition, the recombination probability of carriers in the light emitting material FM can be suppressed. In addition, the phenomenon of the light emitting material FM generating a triplet excited state with recombination of carriers in the light emitting material FM can be suppressed. In addition, excitons may be generated in the first material and the energy of the excitons is transferred to the light emitting material FM through the energy donor material ED. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
(8) In addition, in the light-emitting device according to one embodiment of the present invention, the first HOMO level HOMO1 is higher than the second HOMO level HOMO 2.
Thus, the organometallic complex can easily trap holes. In addition, the probability of recombination of carriers in the organometallic complex can be improved. In addition, an organometallic complex can be used as the energy donor material ED to transfer energy of the energy donor material ED, particularly energy of a triplet excited state, to the light emitting material FM. In addition, the energy donor material ED and the adjacent luminescent material FM are clamped with a first substituent R 1 . In addition, the distance between the centers of the energy donor material ED and the adjacent luminescent material FM may be made suitable. In addition, energy transfer based on the tex mechanism can be suppressed. In addition, energy transfer based on the foster mechanism can be dominant. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
(9) In addition, an embodiment of the present invention is the light emitting device, wherein the first LUMO level LUMO1 is lower than the second LUMO level LUMO 2.
Thus, the organometallic complex can easily capture electrons. In addition, the probability of recombination of carriers in the organometallic complex can be improved. In addition, organometallic complexes can be used as energy donor materials ED to use the energy of the energy donor materials ED, in particularThe energy of the triplet excited state is transferred to the light emitting material FM. In addition, the energy donor material ED and the adjacent luminescent material FM are clamped with a first substituent R 1 . In addition, the distance between the centers of the energy donor material ED and the adjacent luminescent material FM may be made suitable. In addition, energy transfer based on the tex mechanism can be suppressed. In addition, energy transfer based on the foster mechanism can be dominant. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
(10) Further, one embodiment of the present invention is a light-emitting device including the above light-emitting device and a transistor or a substrate.
(11) In addition, one embodiment of the present invention is a display device including the above light-emitting device and a transistor or a substrate.
(12) Another embodiment of the present invention is a lighting device including the above-described light-emitting device and a housing.
(13) Further, one embodiment of the present invention is an electronic device including the display device and a sensor, an operation button, a speaker, or a microphone.
In the drawings of the present specification, components are classified according to their functions and are shown as block diagrams of blocks independent of each other, but it is difficult to completely divide the components according to their functions in practice, and one component involves a plurality of functions.
In addition, the light emitting apparatus in this specification includes an image display device using a light emitting device. In addition, the light emitting device sometimes further includes the following modules: the light emitting device is mounted with a connector such as an anisotropic conductive film or a module of TCP (Tape Carrier Package: tape carrier package); a module provided with a printed wiring board at an end of the TCP; the module of an IC (integrated circuit) is directly mounted On the light emitting device by COG (Chip On Glass) method. Further, the lighting device and the like sometimes include a light emitting device.
Effects of the invention
According to one embodiment of the present invention, a novel light emitting device excellent in convenience, practicality, or reliability can be provided. Further, according to one embodiment of the present invention, a novel electronic device excellent in convenience, practicality, or reliability can be provided. Further, according to one embodiment of the present invention, a novel display device excellent in convenience, practicality, or reliability can be provided. Further, according to one embodiment of the present invention, a novel lighting device excellent in convenience, practicality, or reliability can be provided. Further, according to an embodiment of the present invention, a novel light-emitting device, a novel light-emitting apparatus, a novel electronic device, a novel display apparatus, a novel lighting apparatus, or a novel semiconductor apparatus can be provided.
Note that the description of these effects does not hinder the existence of other effects. Note that one mode of the present invention is not required to have all of the above effects. Effects other than the above-described effects are apparent from the descriptions of the specification, drawings, claims, and the like, and effects other than the above-described effects can be extracted from the descriptions of the specification, drawings, claims, and the like.
Brief description of the drawings
Fig. 1A to 1E are diagrams illustrating a structure of a light emitting device according to an embodiment.
Fig. 2A to 2C are diagrams illustrating a structure of a light emitting device according to an embodiment.
Fig. 3A and 3B are diagrams illustrating a structure of a light emitting device according to an embodiment.
Fig. 4A and 4B are diagrams illustrating a structure of a functional panel according to an embodiment.
Fig. 5A to 5C are diagrams illustrating the structure of a functional panel according to an embodiment.
Fig. 6A and 6B are conceptual views of an active matrix type light emitting device.
Fig. 7A and 7B are conceptual views of an active matrix type light emitting device.
Fig. 8 is a conceptual diagram of an active matrix type light emitting device.
Fig. 9A and 9B are conceptual views of a passive matrix light-emitting device.
Fig. 10A and 10B are diagrams showing the lighting device.
Fig. 11A to 11D are diagrams showing an electronic apparatus.
Fig. 12A to 12C are diagrams showing an electronic device.
Fig. 13 is a diagram showing a lighting device.
Fig. 14 is a diagram showing a lighting device.
Fig. 15 is a diagram showing an in-vehicle display device and a lighting device.
Fig. 16A to 16C are diagrams showing the electronic apparatus.
Fig. 17A to 17C are diagrams illustrating the structure of a light emitting device according to an embodiment.
Fig. 18 is a diagram illustrating an absorption spectrum and an emission spectrum of a material for a light emitting device according to an embodiment.
Fig. 19 is a diagram illustrating an absorption spectrum and an emission spectrum of a material for a light emitting device according to an embodiment.
Fig. 20 is a diagram illustrating an absorption spectrum and an emission spectrum of a material for a light emitting device according to an embodiment.
Fig. 21 is a diagram illustrating an absorption spectrum and an emission spectrum of a material for a light emitting device according to an embodiment.
Fig. 22 is a diagram illustrating current density-luminance characteristics of a light emitting device according to an embodiment.
Fig. 23 is a diagram illustrating luminance-current efficiency characteristics of a light emitting device according to an embodiment.
Fig. 24 is a diagram illustrating voltage-luminance characteristics of a light emitting device according to an embodiment.
Fig. 25 is a diagram illustrating voltage-current characteristics of a light emitting device according to an embodiment.
Fig. 26 is a diagram illustrating luminance-external quantum efficiency characteristics of a light emitting device according to an embodiment.
Fig. 27 is a diagram illustrating an emission spectrum of a light emitting device according to an embodiment.
Fig. 28 is a diagram illustrating normalized luminance-time variation characteristics of the light emitting device according to the embodiment.
Fig. 29 is a diagram illustrating voltage-current characteristics of a reference device according to an embodiment.
Fig. 30 is a diagram illustrating an emission spectrum of a reference device according to an embodiment.
Fig. 31 is a diagram illustrating a change in light emission intensity at the time of pulse driving of the reference device according to the embodiment.
Fig. 32 is a diagram illustrating current density-luminance characteristics of a light emitting device according to an embodiment.
Fig. 33 is a diagram illustrating luminance-current efficiency characteristics of a light emitting device according to an embodiment.
Fig. 34 is a diagram illustrating voltage-luminance characteristics of a light emitting device according to an embodiment.
Fig. 35 is a graph illustrating voltage-current characteristics of a light emitting device according to an embodiment.
Fig. 36 is a diagram illustrating luminance-external quantum efficiency characteristics of a light emitting device according to an embodiment.
Fig. 37 is a diagram illustrating an emission spectrum of a light emitting device according to an embodiment.
Fig. 38 is a diagram illustrating normalized luminance-time variation characteristics of the light emitting device according to the embodiment.
Fig. 39 is a diagram illustrating current density-luminance characteristics of a light emitting device according to an embodiment.
Fig. 40 is a diagram illustrating luminance-current efficiency characteristics of a light emitting device according to an embodiment.
Fig. 41 is a diagram illustrating voltage-luminance characteristics of a light emitting device according to an embodiment.
Fig. 42 is a diagram illustrating voltage-current characteristics of a light emitting device according to an embodiment.
Fig. 43 is a diagram illustrating luminance-external quantum efficiency characteristics of a light emitting device according to an embodiment.
Fig. 44 is a diagram illustrating an emission spectrum of a light emitting device according to an embodiment.
Fig. 45 is a diagram illustrating normalized luminance-time variation characteristics of the light emitting device according to the embodiment.
Fig. 46 is a diagram illustrating normalized luminance-time variation characteristics of the light emitting device according to the embodiment.
Modes for carrying out the invention
A light emitting device of one embodiment of the present invention includes a first electrode, a second electrode, and a first layer,the second electrode includes a region overlapping the first electrode. The first layer is positioned between the first electrode and the second electrode, and the first layer comprises a luminescent material, a first organic compound and a first material. The luminescent material has a function of emitting fluorescence, the luminescent material having an end located at the longest wavelength of the absorption spectrum at the first wavelength. The first organic compound has a function of converting triplet excitation energy into luminescence having an end portion located at the shortest wavelength of the spectrum at a second wavelength, which is located at a short wavelength compared to the first wavelength. In addition, the first organic compound includes a first substituent R 1 A first substituent R 1 Is any of alkyl, cycloalkyl and trialkylsilyl groups. In addition, the first material has a function of emitting delayed fluorescence at room temperature, and a difference between a HOMO level and a LUMO level of the first material is smaller than a difference between a HOMO level and a LUMO level of the first organic compound.
Thereby, the first organic compound can be used as an energy donor material to transfer energy of the energy donor material, particularly energy of a triplet excited state, to the light emitting material. In addition, a first substituent R is sandwiched between the energy donor material and the adjacent luminescent material 1 . In addition, the distance between the centers of the energy donor material and the adjacent luminescent material may be made suitable. In addition, energy transfer based on the tex mechanism can be suppressed. In addition, energy transfer based on the foster mechanism can be dominant. In addition, the light-emitting material can be placed in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material can be improved. In addition, the luminous efficiency can be improved.
In addition, triplet excitons generated by the first material may be converted to singlet excitons. In addition, carriers transferred in the first material may be increased by making a difference between the HOMO level and the LUMO level derived from the first material smaller than a difference between the HOMO level and the LUMO level derived from the first organic compound. In addition, the recombination probability of carriers in the first material can be improved. In addition, energy may be transferred from excitons generated by the first material to the energy donor material. In addition, excitons may be generated in the first material and energy of the excitons is transferred to the light emitting material through the energy donor material. In addition, the light-emitting material can be placed in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
The first layer contains a light emitting material FM and an exciton-trapping (harborest) energy donor material ED (see fig. 1E). Organometallic complexes, TADF materials or exciplex can be used as energy donor material ED. The energy donor material ED and the adjacent luminescent material FM are clamped with substituent R 1 Or substituents R 2 . In addition, the distance between the centers of the energy donor material ED and the adjacent luminescent material FM may be made suitable. In addition, energy transfer based on the Dexter mechanism (Dexter) can be suppressed. In addition, energy transfer based on the forster mechanism (FRET) can be dominant. Note that, in general, the tex mechanism is dominant when the distance between the energy donor material ED and the light emitting material FM is 1nm or less (see fig. 1D), and the foster mechanism is dominant when the distance between the energy donor material ED and the light emitting material FM is 1nm or more and 10nm or less (see fig. 1E). In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. In addition, the reliability can be improved.
The embodiments will be described in detail with reference to the accompanying drawings. It is noted that the present invention is not limited to the following description, but one of ordinary skill in the art can easily understand the fact that the manner and details thereof can be changed into various forms without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments shown below. Note that in the structure of the invention described below, the same reference numerals are used in common in different drawings to show the same portions or portions having the same functions, and repetitive description thereof will be omitted.
(embodiment 1)
In this embodiment mode, a structure of a light emitting device 150 according to an embodiment of the present invention will be described with reference to fig. 1 and 2.
In this specification and the like, a device manufactured using a Metal Mask or FMM (Fine Metal Mask) is sometimes referred to as a device having a MM (Metal Mask) structure. In this specification and the like, a device manufactured without using a metal mask or an FMM is referred to as a device having a MML (Metal Mask Less) structure.
In this specification and the like, a structure in which light-emitting layers are formed or applied to light-emitting devices of respective colors (here, blue (B), green (G), and red (R)) is sometimes referred to as a SBS (Side By Side) structure. In this specification and the like, a light-emitting device that can emit white light is sometimes referred to as a white light-emitting device. A white light emitting device can be used as a light emitting device for full color display by combining with a colored layer (e.g., a color filter).
Further, the light emitting device can be roughly classified into a single structure and a series structure. The single structure device preferably has the following structure: a light emitting unit is included between a pair of electrodes, and the light emitting unit includes one or more light emitting layers. In order to obtain white light emission, the light emitting layers may be selected so that the light emission of two or more light emitting layers is in a complementary relationship. For example, by placing the light emission color of the first light emission layer and the light emission color of the second light emission layer in a complementary relationship, a structure that emits light in white on the whole light emitting device can be obtained. In addition, the same applies to a light-emitting device including three or more light-emitting layers.
The device of the tandem structure preferably has the following structure: two or more light emitting units are included between a pair of electrodes, and each light emitting unit includes one or more light emitting layers. In order to obtain white light emission, a structure may be employed in which light emitted from the light-emitting layers of the plurality of light-emitting units is combined to obtain white light emission. Note that the structure to obtain white light emission is the same as that in the single structure. In the device having the tandem structure, an intermediate layer such as a charge generation layer is preferably provided between the plurality of light emitting cells.
Further, in the case of comparing the above-described white light emitting device (single structure or tandem structure) and the light emitting device of the SBS structure, the power consumption of the light emitting device of the SBS structure can be made lower than that of the white light emitting device. A light emitting device employing an SBS structure is preferable when power consumption reduction is desired. On the other hand, the manufacturing process of the white light emitting device is simpler than that of the SBS structure light emitting device, and thus the manufacturing cost can be reduced or the manufacturing yield can be improved, which is preferable.
< structural example of light-emitting device 150 >
The light-emitting device 150 described in this embodiment mode includes an electrode 101, an electrode 102, and a cell 103 (see fig. 1A). The electrode 102 has a region overlapping with the electrode 101, and the cell 103 has a region sandwiched between the electrode 101 and the electrode 102.
< structural example of cell 103 >
The unit 103 has a single-layer structure or a stacked-layer structure. For example, cell 103 includes layer 111, layer 112, and layer 113. The unit 103 has a function of emitting light EL 1.
Layer 111 has a region sandwiched between layer 112 and layer 113, layer 112 has a region sandwiched between electrode 101 and layer 111, and layer 113 has a region sandwiched between electrode 102 and layer 111.
For example, a layer selected from a functional layer such as a light-emitting layer, a hole-transporting layer, an electron-transporting layer, and a carrier blocking layer may be used for the cell 103. In addition, a layer selected from a functional layer such as a hole injection layer, an electron injection layer, an exciton blocking layer, and a charge generation layer may be used for the cell 103.
Structural example 1 of layer 111
The layer 111 comprises a luminescent material FM, an energy donor material ED and a host material.
Example 1 of luminescent material FM
The luminescent material FM has a function of emitting fluorescence, and the luminescent material FM has an absorption spectrum Abs (see fig. 1C). In addition, the luminescent material FM may be referred to as a fluorescent luminescent material.
The absorption spectrum Abs of the luminescent material FM has an end located at the longest wavelength at the wavelength λabs (nm). Note that the wavelength λabs (nm) can be calculated by the following method: the wavelength at the intersection of the tangent line and the transverse axis is defined as λabs (nm) by dividing the tangent line at a wavelength located at the longest wavelength among wavelengths at which the inclination of the tangent line of the absorption spectrum is extremely small. In other words, λabs (nm) is the absorption end of the absorption spectrum.
Example 2 of luminescent material FM
In addition, the fluorescence emitted by the luminescent material FM has a fluorescence spectrumFluorescence Spectrum->The wavelength λf (nm) has an end portion located at the shortest wavelength (see fig. 1C). λf (nm) can be calculated by the following method: the wavelength at the intersection of the tangent line and the transverse axis is defined as λf (nm) by dividing the tangent line at the wavelength located at the shortest wavelength among the wavelengths at which the inclination of the tangent line of the fluorescence spectrum is extremely large. In other words, λf (nm) is the start (onset) of the short wavelength side of the fluorescence spectrum.
Example 3 of luminescent material FM
For example, the following fluorescent light-emitting substance can be used for the layer 111. Note that the fluorescent light-emitting substance is not limited thereto, and various known fluorescent light-emitting substances can be used for the layer 111.
Specifically, N, N, N ', N' -tetrakis (4-methylphenyl) -9, 10-anthracenediamine (abbreviated as TTPA), N, N-diphenylquinacridone (abbreviated as DPQd), and the like can be used.
[ chemical formula 1]
[ example 1 of energy donor Material ED ]
The energy donor material ED has the function of converting triplet excitation energy into luminescence, and the emission spectrum of the energy donor material EDIncluding a region OLP overlapping the absorption spectrum Abs of the luminescent material FM (refer to fig. 1C). In addition, the region OLP is in the absorption band at the longest wavelength of the absorption spectrum Abs of the luminescent material FM.
For example, an organometallic complex can be used as the energy donor material ED. The organometallic complex has a function of emitting phosphorescence at room temperature, and the phosphorescence spectrum of the organometallic complex overlaps with the absorption spectrum of the luminescent material FM. That is, the emission spectrum of the energy donor material ED overlaps with the absorption spectrum Abs of the luminescent material FM.
The phosphorescence spectrum of the organometallic complex has an end portion at the shortest wavelength at a wavelength λp (nm), and the wavelength λp is at a shorter wavelength than the wavelength λabs (see fig. 1C). Note that λp (nm) can be calculated by the following method: the wavelength at the intersection of the tangent line and the transverse axis is defined as λp (nm) by dividing the tangent line at the wavelength located at the shortest wavelength among the wavelengths at which the inclination of the tangent line of the phosphorescence spectrum is extremely large. In other words, λp (nm) is the start (onset) of the short wavelength side of the phosphorescence spectrum.
Preferably, the relationship between the wavelength λp (nm) and the wavelength λabs (nm) is represented by the following expression (2). Thereby, the absorption band of the luminescent material FM at the longest wavelength better overlaps with the phosphorescence spectrum of the organometallic complex.
[ formula 2]
It is preferable that the relationship between the wavelength λp (nm) and the wavelength λf (nm) is represented by the following expression (3). Thereby, the absorption band of the luminescent material FM at the longest wavelength better overlaps with the phosphorescence spectrum of the organometallic complex.
[ arithmetic 3]
For example, an organometallic complex can be used as the energy donor material ED. The organometallic complex comprises a ligand comprising a substituent R 1 . Substituent R 1 Is any of alkyl, cycloalkyl and trialkylsilyl groups.
Note that the number of the components to be processed,at substituent R 1 In the case of an alkyl group, the number of carbon atoms of the alkyl group is 3 or more and 12 or less, and the substituent R is 1 In the case of cycloalkyl, the number of ring-forming carbon atoms of the cycloalkyl is 3 or more and 10 or less, and the substituent R is 1 In the case of a trialkylsilyl group, the number of carbon atoms of the trialkylsilyl group is 3 or more and 12 or less.
Examples of the secondary or tertiary alkyl group having 3 to 12 carbon atoms include branched alkyl groups such as isopropyl and tert-butyl. The branched alkyl group is not limited thereto. Examples of the cycloalkyl group having 3 to 10 carbon atoms include cyclopropyl, cyclobutyl, cyclohexyl, norbornyl, and adamantyl. The cycloalkyl group is not limited thereto. When the cycloalkyl group has a substituent, examples of the substituent include an alkyl group having 1 to 7 carbon atoms such as a methyl group, an isopropyl group and a tert-butyl group, a cycloalkyl group having 5 to 7 carbon atoms such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and an 8,9, 10-trinorbornyl group, an aryl group having 6 to 12 carbon atoms such as a phenyl group, a naphthyl group and a biphenyl group, and the like. Examples of the trialkylsilyl group having 3 to 12 carbon atoms include trimethylsilyl group, triethylsilyl group, and t-butyldimethylsilyl group. The trialkylsilyl group is not limited thereto.
For example, substituent R 1 Heavy hydrogen may be included instead of hydrogen. This can suppress the release of hydrogen. In addition, the reliability of the light emitting device can be improved.
The organometallic complex has a first HOMO level HOMO1 and a first LUMO level LUMO1 (see fig. 1B).
Example 2 of energy donor Material ED
The organometallic complex can be used as an energy donor material ED. The organometallic complex comprises a ligand and a transition metal. For example, a transition metal may be used as the center metal. In particular, an organometallic complex having iridium or platinum as a central metal is preferably used. Thus, a radiative triplet excited state can be obtained. In addition, the organometallic complex can be chemically stable. The ligand near the central metal is particularly preferably trivalent iridium because it tends to form a bulky structure, and as a result, it is easy to suppress the transfer of the tex.
The ligand comprises a first ring and a second ring, at least one substituent R 1 Is bonded to at least one of the first ring and the second ring.
Note that the first ring is a six-membered ring, and atoms including covalent bonds with transition metals as constituent atoms. The second ring is a five-membered ring or a six-membered ring, and contains an atom coordinated to a transition metal as a constituent atom. In addition, the first ring is preferably a benzene ring. In addition, the constituent atom coordinated to the transition metal may be N such as a pyridine ring, or C such as carbene.
Example 3 of energy donor Material ED
For example, an organometallic complex can be used as the energy donor material ED. The organometallic complex includes a ligand.
The ligand comprises a phenylpyridine skeleton, at least one substituent R 1 A carbon bonded to the phenylpyridine skeleton.
[ example 4 of energy donor Material ED ]
For example, an organometallic complex represented by the following general formula (G0) can be used as the energy donor material ED.
[ chemical formula 2]
In the above general formula, L is a ligand, and n is an integer of 1 to 3. Further, n is preferably an integer of 2 or more. Thereby, energy transfer by the tex mechanism can be suppressed. In addition, energy transfer based on the foster mechanism can be dominant.
In addition, R 101 To R 108 Is hydrogen or a substituent, R 101 To R 108 Including any one or more of alkyl, substituted or unsubstituted cycloalkyl, and trialkylsilyl. The alkyl group is preferably an alkyl group having 3 to 12 carbon atoms, the cycloalkyl group is preferably 3 to 10 carbon atoms, and the trialkylsilyl group is preferably 3 to 12 carbon atoms. In other words the first and second phase of the process,the above substituent R 1 Included in R 101 To R 108 Is a kind of medium.
Thereby, the light emitting efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
[ example 5 of energy donor Material ED ]
For example, two ligands have a phenylpyridine skeleton and a substituent bonded to a carbon of the phenylpyridine skeleton. For example, a secondary or tertiary alkyl group having 3 or more and 12 or less carbon atoms, a cycloalkyl group having 3 or more and 12 or less carbon atoms, or a trialkylsilyl group having 3 or more and 12 or less carbon atoms may be used as a substituent.
Specific examples of the organic compound having the above-described structure are shown below.
[ chemical formula 3]
[ example 6 of energy donor Material ED ]
For example, three ligands have a phenylpyridine skeleton and a single or multiple substituents bonded to the carbon of the phenylpyridine skeleton. For example, a secondary or tertiary alkyl group having 3 or more and 12 or less carbon atoms, a cycloalkyl group having 3 or more and 12 or less carbon atoms, or a trialkylsilyl group having 3 or more and 12 or less carbon atoms may be used as a substituent. In addition, ligands having the same structure may be used as two of the three ligands.
Specific examples of the organic compound having the above-described structure are shown below.
[ chemical formula 4]
Example 7 of energy donor Material ED
For example, three ligands have a phenylpyridine skeleton and a substituent bonded to a carbon of the phenylpyridine skeleton. For example, a secondary or tertiary alkyl group having 3 or more and 12 or less carbon atoms, a cycloalkyl group having 3 or more and 12 or less carbon atoms, or a trialkylsilyl group having 3 or more and 12 or less carbon atoms may be used as a substituent. In addition, ligands having the same structure may be used as the three ligands.
Specific examples of the organic compound having the above-described structure are shown below.
[ chemical formula 5]
Example 8 of energy donor Material ED
For example, the ligand has a phenylpyridine skeleton and a substituent bonded to a carbon of the phenylpyridine skeleton. For example, a secondary or tertiary alkyl group having 3 or more and 12 or less carbon atoms, a cycloalkyl group having 3 or more and 12 or less carbon atoms, or a trialkylsilyl group having 3 or more and 12 or less carbon atoms may be used as a substituent, and a substituent in which part or all of hydrogen is substituted with a heavy hydrogen may be used as the substituent. Thereby, the reliability can be improved.
Specific examples of the organic compound having the above-described structure are shown below.
[ chemical formula 6]
[ example 9 of energy donor Material ED ]
An organic compound having a function of emitting delayed fluorescence at room temperature may be used for the energy donor material ED. For example, a substance exhibiting thermally activated delayed fluorescence may be used for the energy donor material ED. The TADF material has a function of emitting delayed fluorescence at room temperature, and the emission spectrum overlaps with the absorption spectrum of the luminescent material FM.
The emission spectrum of the TADF material has an end portion at the shortest wavelength at a wavelength λp (nm), and the wavelength λp is at a shorter wavelength than the wavelength λabs (see fig. 1C). Note that λp (nm) can be calculated by the following method: the wavelength at the intersection of the tangent line and the transverse axis is defined as λp (nm) by dividing the tangent line at the wavelength located at the shortest wavelength among the wavelengths at which the inclination of the tangent line of the emission spectrum is extremely large. In other words, λp (nm) is the start (onset) of the short wavelength side of the emission spectrum.
Preferably, the relationship between the wavelength λp (nm) and the wavelength λabs (nm) is represented by the following expression (2). The absorption band of the luminescent material FM at the longest wavelength thus better overlaps the emission spectrum of the TADF material.
[ calculation formula 4]
It is preferable that the relationship between the wavelength λp (nm) and the wavelength λf (nm) is represented by the following expression (3). The absorption band of the luminescent material FM at the longest wavelength thus better overlaps the emission spectrum of the TADF material.
[ calculation formula 5]
For example, TADF material may be used as the energy donor material ED. The TADF material comprises a substituent R 1 . Substituent R 1 Is any of alkyl, cycloalkyl and trialkylsilyl groups.
Note that at substituent R 1 In the case of an alkyl group, the number of carbon atoms of the alkyl group is 3 or more and 12 or less, and the substituent R is 1 In the case of cycloalkyl, the number of ring-forming carbon atoms of the cycloalkyl is 3 or more and 10 or less, and the substituent R is 1 In the case of a trialkylsilyl group, the number of carbon atoms of the trialkylsilyl group is 3 or more and 12 or less.
For example, substituent R 1 Heavy hydrogen may be included instead of hydrogen. This can suppress the release of hydrogen. In addition, the reliability of the light emitting device can be improved.
The TADF material has a first HOMO level HOMO1 and a first LUMO level LUMO1 (see fig. 1B).
[ example 1 of host Material ]
The host material has a function of emitting delayed fluorescence at room temperature. Note that the first material may be used for the host material. The host material is a material having a weight ratio in the light-emitting layer that is at least larger than that of the light-emitting material, and more preferably has the largest weight ratio in the light-emitting layer. For example, a substance exhibiting thermally activated delayed fluorescence may be used for the host material. Specifically, the TADF material exemplified below can be used for the host material. Note that, not limited thereto, various known TADF materials may be used for the host material.
For example, fullerene and its derivatives, acridine and its derivatives, eosin derivatives, and the like can be used for TADF materials. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), or the like can be used for TADF materials.
Specifically, a protoporphyrin-tin fluoride complex (SnF) represented by the following structural formula can be used 2 (protoIX)), mesoporphyrin-tin fluoride complex (SnF) 2 (Meso IX)), hematoporphyrin-tin fluoride complex (SnF) 2 (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF) 2 (Copro III-4 Me), octaethylporphyrin-tin fluoride Complex (SnF) 2 (OEP)), protoporphyrin-tin fluoride complex (SnF) 2 (Etio I)) and octaethylporphyrin-platinum chloride complex (PtCl) 2 OEP), and the like.
[ chemical formula 7]
In addition, for example, a heterocyclic compound having one or both of a pi-electron rich heteroaromatic ring and a pi-electron deficient heteroaromatic ring may be used for the TADF material.
Specifically, 2- (biphenyl-4-yl) -4, 6-bis (12-phenylindol-2, 3-a ] carbazol-11-yl) -1,3, 5-triazine (abbreviated as PIC-TRZ), 9- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) -9' -phenyl-9H, 9' H-3,3' -dicarbazole (abbreviated as PCCzTzn), 2- {4- [3- (N-phenyl-9H-carbazol-3-yl) -9H-carbazol-9-yl ] phenyl } -4, 6-diphenyl-1, 3, 5-triazine (abbreviated as PCCzPTzn), 2- [4- (10H-phenoxazin-10-yl) phenyl ] -4, 6-diphenyl-1, 3, 5-triazine (abbreviated as PXZ-TRZ), 3- [4- (5-phenyl-5, 10-dihydrophenazin-10-yl) phenyl ] -4, 5-diphenyl-1, 2H-carbazol-9-yl) phenyl } -4, 6-diphenyl-1, 3, 5-triazine (abbreviated as PCCzPTzn), 2- (10H-phenoxazin-10-yl) phenyl ] -4, 6-diphenyl-1, 3, 5-triazine (abbreviated as PPRXN-9-H-9-p-dioxanone) can be used, 9-dimethyl-9, 10-dihydroacridine) phenyl ] sulfolane (abbreviation: DMAC-DPS), 10-phenyl-10 h,10' h-spiro [ acridine-9, 9' -anthracene ] -10' -one (abbreviation: ACRSA), and the like.
[ chemical formula 8]
In addition, the heterocyclic compound has a pi-electron rich type heteroaromatic ring and a pi-electron deficient type heteroaromatic ring, and both of the electron transport property and the hole transport property are high, so that it is preferable. In particular, among the backbones having a pi electron deficient heteroaromatic ring, a pyridine backbone, a diazine backbone (pyrimidine backbone, pyrazine backbone, pyridazine backbone) and a triazine backbone are preferable because they are stable and have good reliability. In particular, benzofuropyrimidine skeleton, benzothiophenopyrimidine skeleton, benzofuropyrazine skeleton, and benzothiophenopyrazine skeleton are preferable because they have high acceptors and good reliability.
Among the backbones having a pi-electron rich heteroaromatic ring, the acridine backbone, the phenoxazine backbone, the phenothiazine backbone, the furan backbone, the thiophene backbone, and the pyrrole backbone are stable and have good reliability, and therefore, it is preferable to have at least one of the foregoing backbones. The furan skeleton is preferably a dibenzofuran skeleton, and the thiophene skeleton is preferably a dibenzothiophene skeleton. As the pyrrole skeleton, an indole skeleton, a carbazole skeleton, an indolocarbazole skeleton, a dicarbazole skeleton, and a 3- (9-phenyl-9H-carbazol-3-yl) -9H-carbazole skeleton are particularly preferably used.
Among the materials in which the pi electron-rich heteroaromatic ring and the pi electron-deficient heteroaromatic ring are directly bonded, those in which both the electron donating property of the pi electron-rich heteroaromatic ring and the electron accepting property of the pi electron-deficient heteroaromatic ring are high and the energy difference between the S1 energy level and the T1 energy level is small, and thus thermally activated delayed fluorescence can be obtained efficiently are particularly preferable. In addition, instead of pi-electron deficient heteroaromatic rings, aromatic rings to which electron withdrawing groups such as cyano groups are bonded may be used. Further, as the pi-electron rich skeleton, an aromatic amine skeleton, a phenazine skeleton, or the like can be used.
Examples of the pi electron-deficient skeleton include a xanthene skeleton, thioxanthene dioxide (thioxanthene dioxide) skeleton, oxadiazole skeleton, triazole skeleton, imidazole skeleton, anthraquinone skeleton, boron-containing skeleton such as phenylborane and boran, aromatic or heteroaromatic ring having a nitrile group or a cyano group such as benzonitrile and cyanobenzene, carbonyl skeleton such as benzophenone, phosphine oxide skeleton and sulfone skeleton.
In this way, a pi electron-deficient backbone and a pi electron-rich backbone may be used in place of at least one of the pi electron-deficient heteroaryl ring and the pi electron-rich heteroaryl ring.
[ example 2 of host Material ]
In addition, a material in which a plurality of substances are mixed may be used for the host material. In other words, a material in which a plurality of substances are mixed may be used for the first material. For example, a mixed material composed of a mixture of a substance a and a substance B, which form an exciplex, may be used for the host material. Preferably, a mixed material of a material having hole-transporting property and a material having electron-transporting property may be used for the host material. Note that the weight ratio of the hole-transporting material to the electron-transporting material in the mixed material may be (hole-transporting material/electron-transporting material) = (1/19) or more and (19/1) or less. This makes it possible to easily adjust the carrier transport property of the layer 111. In addition, the control of the composite region can be performed easily.
The HOMO level of the material having hole-transporting property is preferably not less than the HOMO level of the material having electron-transporting property. Alternatively, the LUMO level of the material having hole-transporting property is preferably equal to or higher than the LUMO level of the material having electron-transporting property. Thus, an exciplex can be efficiently formed. The LUMO level and HOMO level of the material can be obtained from electrochemical characteristics (reduction potential and oxidation potential). Specifically, the reduction potential and the oxidation potential can be measured by Cyclic Voltammetry (CV) measurement.
The formation of exciplex can be confirmed, for example, by the following method: comparing the emission spectrum of a material having hole-transporting property, the emission spectrum of a material having electron-transporting property, and the emission spectrum of a mixed film obtained by mixing these materials, it is explained that an exciplex is formed when a phenomenon is observed in which the emission spectrum of the mixed film shifts to the long wavelength side (or has a new peak on the long wavelength side) than the emission spectrum of each material. Alternatively, when transient Photoluminescence (PL) of a material having hole-transporting property, transient PL of a material having electron-transporting property, and transient PL of a mixed film obtained by mixing these materials are compared, transient PL of the mixed film is observed to have a long lifetime component or a transient response such as a ratio of a delayed component being larger than the transient PL lifetime of each material, the formation of an exciplex is described. In addition, the above-described transient PL may be referred to as transient Electroluminescence (EL). In other words, the formation of an exciplex can be confirmed by observing the difference in transient response from the transient EL of a material having hole-transporting property, the transient EL of a material having electron-transporting property, and the transient EL of a mixed film of these materials.
[ example 3 of host Material ]
The first material for the host material has a second HOMO level HOMO2 and a second LUMO level LUMO2. Note that when a mixed material of a plurality of substances is used for the host material, the highest HOMO level among HOMO levels of the plurality of materials may be used as the second HOMO level HOMO2. In addition, the lowest LUMO level among the LUMO levels of the plurality of materials may be used as the second LUMO level LUMO2.
The first HOMO level HOMO1, the first LUMO level LUMO1, the second HOMO level HOMO2, and the second LUMO level LUMO2 satisfy the following expression (1).
[ arithmetic 6]
(LUMO2-HOMO2)＜(LUMO1-HOMO1)···(1)
Thus, organometallic complexes or TADF can be usedThe material acts as an energy donor material ED to transfer energy of the energy donor material ED, in particular energy of the triplet excited state, to the luminescent material FM. In addition, the energy donor material ED and the adjacent luminescent material FM are clamped with a substituent R 1 . In addition, the distance between the centers of the energy donor material ED and the adjacent luminescent material FM may be made suitable. In addition, energy transfer based on the tex mechanism can be suppressed. In addition, energy transfer based on the foster mechanism can be dominant. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved.
In addition, triplet excitons generated by the host material may be converted into singlet excitons. In addition, carriers transferred in the host material may be increased by making the difference between the HOMO level and the LUMO level derived from the host material smaller than the difference between the HOMO level and the LUMO level derived from the energy donor material ED. In addition, the recombination probability of carriers in the host material can be improved. In addition, energy may be transferred from excitons generated by the host material to the energy donor material ED. In addition, excitons may be generated in the host material and the energy of the excitons is transferred to the light emitting material FM through the energy donor material ED. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
[ example 4 of host Material ]
The second HOMO level HOMO2 of the host material is higher than the first HOMO level HOMO1 of the energy donor material ED (see fig. 1B). In addition, the second LUMO level LUMO2 of the host material is lower than the first LUMO level LUMO1 of the energy donor material ED.
This can increase carriers transferred in the host material. In addition, the recombination probability of carriers in the host material can be improved. In addition, energy may be transferred from excitons generated by the host material to the energy donor material ED. In addition, excitons may be generated in the host material and the energy of the excitons is transferred to the light emitting material FM through the energy donor material ED. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
Example 4 of luminescent material FM
Preferred luminescent materials FM which can be used in the light emitting device of one embodiment of the invention comprise at least one substituent R 2 。
Substituent R 2 Selected from methyl, branched alkyl, substituted or unsubstituted cycloalkyl, and trialkylsilyl. Note that at substituent R 2 In the case of a branched alkyl group, the number of carbon atoms of the branched alkyl group is 3 or more and 12 or less, and the substituent R is 2 In the case of cycloalkyl, the number of ring-forming carbon atoms of the cycloalkyl is 3 or more and 10 or less, and the substituent R is 2 In the case of a trialkylsilyl group, the number of carbon atoms of the trialkylsilyl group is 3 or more and 12 or less.
Examples of the secondary or tertiary alkyl group having 3 to 12 carbon atoms include branched alkyl groups such as isopropyl and tert-butyl. The branched alkyl group is not limited thereto. Examples of the cycloalkyl group having 3 to 10 carbon atoms include cyclopropyl, cyclobutyl, cyclohexyl, norbornyl, and adamantyl. The cycloalkyl group is not limited thereto. When the cycloalkyl group has a substituent, examples of the substituent include an alkyl group having 1 to 7 carbon atoms such as a methyl group, an isopropyl group and a tert-butyl group, a cycloalkyl group having 5 to 7 carbon atoms such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and an 8,9, 10-trinorbornyl group, an aryl group having 6 to 12 carbon atoms such as a phenyl group, a naphthyl group and a biphenyl group, and the like. Examples of the trialkylsilyl group having 3 to 12 carbon atoms include trimethylsilyl group, triethylsilyl group, and t-butyldimethylsilyl group. The trialkylsilyl group is not limited thereto.
At substituent R 2 In the case of an alkyl group having a branched chain, for example, a secondary alkyl group or a tertiary alkyl group can be used as the substituent R 2 . Specifically, an alkyl group having a branched chain of carbon bonded to the parent skeleton may be used as the substituent R 2 . Thus, the number of alpha hydrogens can be reduced. In addition, the reliability of the light emitting device can be improved.
At substituent R 2 In the case of an alkyl group having a branched chain, for example, an alkyl group having 3 or more and 4 or less carbon atoms may be used as the substituent R 2 。
At substituent R 2 In the case of cycloalkyl, for example, cycloalkyl having 3 or more and 6 or less carbon atoms can be used as the substituent R 2 。
At substituent R 2 In the case of trialkylsilyl groups, trimethylsilyl groups can be used as substituents R 2 。
Whereby the luminescent material FM and the adjacent energy donor material ED are sandwiched with a substituent R 2 . In addition, the distance between the centers of the energy donor material ED and the adjacent luminescent material FM may be made suitable. In addition, energy transfer based on the tex mechanism can be suppressed. In addition, energy transfer based on the foster mechanism can be dominant. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
For example, substituent R 2 Heavy hydrogen may be included instead of hydrogen. This can suppress the release of hydrogen. In addition, the reliability of the light emitting device can be improved.
Example 5 of luminescent material FM
The light-emitting material FM which can be used in the light-emitting device of one embodiment of the present invention has a condensed aromatic ring or condensed heteroaromatic ring and five or more substituents R 2 。
The condensed aromatic ring or the condensed heteroaromatic ring is 3-10 rings. In addition, more than five substituents R 2 Each independently includes an alkyl group having a branch, a substituted or unsubstituted cycloalkyl group, or a trialkylsilyl group. In other words, at least five substituents R 2 Not methyl. Note that at substituent R 2 In the case of a branched alkyl group, the number of carbon atoms of the branched alkyl group is 3 or more and 12 or less, and the substituent R is 2 In the case of cycloalkyl, the number of ring-forming carbon atoms of the cycloalkyl is 3 or more and 10 or less, and the substituent R is 2 In the case of a trialkylsilyl group, the number of carbon atoms of the trialkylsilyl group is 3 or more and 12 or less.
Example 6 of luminescent material FM
The light-emitting material FM which can be used in the light-emitting device of one embodiment of the present invention has a condensed aromatic ring or condensed heteroaromatic ring and three or more substituents R 2 。
The condensed aromatic ring or the condensed heteroaromatic ring is 3-10 rings. In addition, more than three substituents R 2 Is not directly bonded to a condensed aromatic ring or a condensed heteroaromatic ring. In addition, more than three substituents R 2 Each independently includes an alkyl group, a substituted or unsubstituted cycloalkyl group, or a trialkylsilyl group. In addition, at substituent R 2 In the case of an alkyl group, the number of carbon atoms of the alkyl group is 3 or more and 12 or less, and the substituent R is 2 In the case of cycloalkyl, the number of ring-forming carbon atoms of the cycloalkyl is 3 or more and 10 or less, and the substituent R is 2 In the case of a trialkylsilyl group, the number of carbon atoms of the trialkylsilyl group is 3 or more and 12 or less.
Example 7 of luminescent material FM
The light emitting material FM that can be used in the light emitting device of one embodiment of the present invention has a condensed aromatic ring or a condensed heteroaromatic ring and a diarylamino group.
The condensed aromatic ring or the condensed heteroaromatic ring is 3-10 rings. In addition, the nitrogen atom of the diarylamino group is bonded to a condensed aromatic ring or condensed heteroaromatic ring, and the aryl group of the diarylamino group is bonded to the substituent R 2 。
Example 8 of luminescent material FM
For example, an organic compound represented by the following general formula (G1) can be used as the light emitting material FM.
[ chemical formula 9]
In the above formula, A is a pi conjugated system, and for example, a condensed aromatic ring or a condensed heteroaromatic ring may be used as A. Specifically, a condensed aromatic ring of 3 rings or more and 10 rings or less or a condensed heteroaromatic ring of 3 rings or more and 10 rings or less may be used as a.
In addition, R 211 To R 242 Is hydrogen or a substituent, R 211 To R 242 Including any one or more of alkyl groups having a branched chain, substituted or unsubstituted cycloalkyl groups, and trialkylsilyl groups. The alkyl group having a branched chain is preferably a secondary or tertiary alkyl group having 3 to 12 carbon atoms, the cycloalkyl group preferably has 3 to 10 carbon atoms, and the trialkylsilyl group preferably has 3 to 12 carbon atoms. In other words, the above substituent R 2 Included in R 211 To R 242 Is a kind of medium.
In addition, N is a nitrogen atom, ar 1 To Ar 4 Is aryl. In other words, the luminescent material FM has a diarylamino group. The nitrogen atom of the diarylamino group being bound to A and the aryl group of the diarylamino group being bound to the substituent R 2 . Furthermore, the luminescent material FM preferably has two or more diarylamines.
Example 9 of luminescent material FM
For example, an organic compound represented by the following general formula (G2) or general formula (G3) may be used as the light emitting material FM.
[ chemical formula 10]
[ chemical formula 11]
In the above formula, R 211 To R 258 Is hydrogen or a substituent, R 211 To R 258 Comprising alkyl groups, substituted or having branchesAny one or more of unsubstituted cycloalkyl and trialkylsilyl groups. The alkyl group having a branched chain is preferably a secondary or tertiary alkyl group having 3 to 12 carbon atoms, the cycloalkyl group preferably has 3 to 10 carbon atoms, and the trialkylsilyl group preferably has 3 to 12 carbon atoms. In other words, the above substituent R 2 Included in R 211 To R 258 Is a kind of medium.
Example 10 of luminescent material FM
For example, an organic compound represented by the following general formula (G4) or general formula (G5) may be used as the light emitting material FM.
[ chemical formula 12]
[ chemical formula 13]
In the above formula, R 211 To R 258 Is hydrogen or a substituent, R 211 To R 258 Including any one or more of alkyl groups having a branched chain, substituted or unsubstituted cycloalkyl groups, and trialkylsilyl groups. The alkyl group having a branched chain is preferably a secondary or tertiary alkyl group having 3 to 12 carbon atoms, the cycloalkyl group preferably has 3 to 10 carbon atoms, and the trialkylsilyl group preferably has 3 to 12 carbon atoms. In other words, the above substituent R 2 Included in R 211 To R 258 In which the substituents R in the diarylamino group 2 Is bonded to a carbon atom located in the meta position to the carbon atom of the benzene ring bonded to the nitrogen atom.
Thus, the organometallic complex can be used as an energy donor material ED to transfer energy of the energy donor material ED, particularly energy of a triplet excited state, to the light emitting material FM. In addition, the energy donor material ED and the adjacent luminescent material FM are clamped with a first substituent R 1 A second substituent R 2 . In addition, the German-based can be suppressedEnergy transfer by the kerster mechanism. In addition, energy transfer based on the foster mechanism can be dominant. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency of the luminescent material FM can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
Specific examples of the organic compound having the above-described structure are shown below.
[ chemical formula 14]
[ chemical formula 15]
[ chemical formula 16]
[ chemical formula 17]
Example 10 of luminescent material FM
The light emitting material FM has a third LUMO energy level LUMO3 (refer to fig. 1B). The third LUMO level LUMO3 is higher than the second LUMO level LUMO2 of the host material.
Thereby, electrons can be suppressed from being trapped in the luminescent material FM. In addition, the recombination probability of carriers in the light emitting material FM can be suppressed. In addition, the phenomenon of the light emitting material FM generating a triplet excited state with recombination of carriers in the light emitting material FM can be suppressed. In addition, excitons may be generated in the host material and the energy of the excitons is transferred to the light emitting material FM through the energy donor material ED. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
Structural example 2 of layer 111
The layer 111 comprises a luminescent material FM, an energy donor material ED and a host material. Note that structural example 2 of the layer 111 is different from structural example 1 of the layer 111 in that the layer 111 contains a trapping level of carriers.
Example 2 of energy donor Material ED
The first HOMO level HOMO1 of the energy donor material ED is higher than the second HOMO level HOMO2 of the host material (see fig. 2A).
Thus, the energy donor material ED can be made to easily trap holes. In addition, the recombination probability of carriers in the energy donor material ED can be improved. In addition, an organometallic complex or TADF material may be used as the energy donor material ED to transfer energy of the energy donor material ED, particularly energy of a triplet excited state, to the light emitting material FM. In addition, the energy donor material ED and the adjacent luminescent material FM are clamped with a substituent R 1 . In addition, the distance between the centers of the energy donor material ED and the adjacent luminescent material FM may be made suitable. In addition, energy transfer based on the tex mechanism can be suppressed. In addition, energy transfer based on the foster mechanism can be dominant. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
Example 3 of energy donor Material ED
The energy donor material ED has a first LUMO level LUMO1 lower than a second LUMO level LUMO2 of the host material (see FIG. 2B).
Thus, the energy donor material ED can be made to easily capture electrons. In addition, the recombination probability of carriers in the energy donor material ED can be improved. In addition, organometallic complexes or TADF materials can be used as energy donor materialsED transfers the energy of the energy donor material ED, in particular the triplet excited state, to the luminescent material FM. In addition, the energy donor material ED and the adjacent luminescent material FM are clamped with a substituent R 1 . In addition, the distance between the centers of the energy donor material ED and the adjacent luminescent material FM may be made suitable. In addition, energy transfer based on the tex mechanism can be suppressed. In addition, energy transfer based on the foster mechanism can be dominant. In addition, the light emitting material FM can be put in a singlet excited state. In addition, the probability of occurrence of a singlet excited state in the light emitting material FM can be improved. In addition, the luminous efficiency can be improved. As a result, a novel light emitting device excellent in convenience, practicality, and reliability can be provided.
Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification.
(embodiment 2)
In this embodiment mode, a structure of a light emitting device 150 according to an embodiment of the present invention will be described with reference to fig. 1 and 2.
< structural example of light-emitting device 150 >
The light emitting device 150 described in this embodiment mode includes an electrode 101, an electrode 102, and a unit 103. The electrode 102 has a region overlapping with the electrode 101, and the cell 103 has a region sandwiched between the electrode 101 and the electrode 102.
< structural example of cell 103 >
The unit 103 has a single-layer structure or a stacked-layer structure. For example, the cell 103 includes a layer 111, a layer 112, and a layer 113 (see fig. 1A). The unit 103 has a function of emitting light EL 1.
For example, a layer selected from a functional layer such as a light-emitting layer, a hole-transporting layer, an electron-transporting layer, and a carrier blocking layer may be used for the cell 103.
Layer 111 has a region sandwiched between layer 112 and layer 113, layer 112 has a region sandwiched between electrode 101 and layer 111, and layer 113 has a region sandwiched between electrode 102 and layer 111. For example, the structure described in embodiment mode 1 can be used for the layer 111.
Structural example of layer 112
For example, a material having hole-transporting property may be used for the layer 112. In addition, the layer 112 may be referred to as a hole transport layer. Note that a material whose band gap is larger than that of the light-emitting material in the layer 111 is preferably used for the layer 112. Therefore, energy transfer of excitons generated from the layer 111 to the layer 112 can be suppressed.
[ Material having hole-transporting property ]
Hole mobility can be set to 1×10 -6 cm 2 The material of/Vs or more is suitable for use as a material having hole-transporting property.
For example, an amine compound or an organic compound having a pi-electron-rich heteroaromatic ring skeleton may be used as the material having hole-transporting property. Specifically, a compound having an aromatic amine skeleton, a compound having a carbazole skeleton, a compound having a thiophene skeleton, a compound having a furan skeleton, or the like can be used. In particular, a compound having an aromatic amine skeleton or a compound having a carbazole skeleton is preferable because it has good reliability and high hole-transporting property and contributes to reduction of driving voltage.
As the compound having an aromatic amine skeleton, for example, 4 '-bis [ N- (1-naphthyl) -N-phenylamino ] biphenyl (abbreviated as NPB), N' -bis (3-methylphenyl) -N, N '-diphenyl- [1,1' -biphenyl ] -4,4 '-diamine (abbreviated as TPD), 4' -bis [ N- (spiro-9, 9 '-dibenzofuran-2-yl) -N-phenylamino ] biphenyl (abbreviated as BSPB), 4-phenyl-4' - (9-phenylfluoren-9-yl) triphenylamine (abbreviated as BPAFLP), 4-phenyl-3 '- (9-phenylfluoren-9-yl) triphenylamine (abbreviated as mPAFLP), 4-phenyl-4' - (9-phenyl-9H-carbazole-3-yl) triphenylamine (abbreviated as A1 BP), 4 '-diphenyl-4 "- (9-phenyl-9H-carbazole-3-yl) triphenylamine (abbreviated as PCBA1 BP), 4- (1-naphthyl) -4' - (9-phenylfluoren-9-yl) triphenylamine (abbreviated as PCBA) and PCBA (abbreviated as PCBA B, 4 '-bis (1-naphthyl) -4"- (9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviated as PCBAIB), 9-dimethyl-N-phenyl-N- [4- (9-phenyl-9H-carbazol-3-yl) phenyl ] fluoren-2-amine (abbreviated as PCBAF), N-phenyl-N- [4- (9-phenyl-9H-carbazol-3-yl) phenyl ] spiro-9, 9' -dibenzofuran-2-amine (abbreviated as PCBASF) and the like.
Examples of the compound having a carbazole skeleton include 1, 3-bis (N-carbazolyl) benzene (abbreviated as mCP), 4 '-bis (N-carbazolyl) biphenyl (abbreviated as CBP), 3, 6-bis (3, 5-diphenylphenyl) -9-phenylcarbazole (abbreviated as CzTP), and 3,3' -bis (9-phenyl-9H-carbazole) (abbreviated as PCCP).
As the compound having a thiophene skeleton, for example, 4' - (benzene-1, 3, 5-triyl) tris (dibenzothiophene) (abbreviated as DBT 3P-II), 2, 8-diphenyl-4- [4- (9-phenyl-9H-fluoren-9-yl) phenyl ] dibenzothiophene (abbreviated as DBTFLP-III), 4- [4- (9-phenyl-9H-fluoren-9-yl) phenyl ] -6-phenyldibenzothiophene (abbreviated as DBTFLP-IV) and the like can be used.
As the compound having a furan skeleton, for example, 4' - (benzene-1, 3, 5-triyl) tris (dibenzofuran) (abbreviated as DBF 3P-II), 4- {3- [3- (9-phenyl-9H-fluoren-9-yl) phenyl ] phenyl } dibenzofuran (abbreviated as mmDBFFLBi-II) and the like can be used.
Structural example of layer 113
For example, a material having electron-transporting property, a material having an anthracene skeleton, a mixed material, or the like can be used for the layer 113. In addition, the layer 113 may be referred to as an electron transport layer. Note that a material whose band gap is larger than that of the light-emitting material in the layer 111 is preferably used for the layer 113. Therefore, energy transfer of excitons generated from the layer 111 to the layer 113 can be suppressed.
[ Material having Electron-transporting Property ]
For example, a metal complex or an organic compound having a pi-electron deficient heteroaromatic ring skeleton may be used as the material having electron-transporting properties.
The following materials may be suitably used for the material having electron-transporting properties: at electric field strength [ V/cm ]]At 600 square root, electron mobility of 1×10 -7 cm 2 above/Vs and 5X 10 -5 cm 2 Materials below/Vs. Thereby, the transmissibility of electrons in the electron transport layer can be controlled. In addition, the electron injection amount into the light emitting layer can be controlled. In addition, the light-emitting layer can be prevented from becoming too many electrons.
As metal complexes, it is possible to use, for example, bis (10-hydroxybenzo [ h ]]Quinoline) beryllium (II) (abbreviation: beBq 2 ) Bis (2-methyl-8-hydroxyquinoline) (4)-phenylphenol) aluminum (III) (abbreviation: BAlq), bis (8-hydroxyquinoline) zinc (II) (abbreviation: znq), bis [2- (2-benzoxazolyl) phenol]Zinc (II) (ZnPBO for short), bis [2- (2-benzothiazolyl) phenol]Zinc (II) (abbreviated as ZnBTZ), and the like.
As the organic compound including a pi-electron deficient heteroaromatic ring skeleton, for example, a heterocyclic compound having a polyazole (polyazole) skeleton, a heterocyclic compound having a diazine skeleton, a heterocyclic compound having a pyridine skeleton, a heterocyclic compound having a triazine skeleton, or the like can be used. In particular, a heterocyclic compound having a diazine skeleton or a heterocyclic compound having a pyridine skeleton has good reliability, and is therefore preferable. In addition, a heterocyclic compound having a diazine (pyrimidine or pyrazine) skeleton has high electron-transporting property, and the driving voltage can be reduced.
As the heterocyclic compound having a polyoxazole skeleton, for example, 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3, 4-oxadiazole (abbreviated as: PBD), 3- (4-biphenyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2, 4-triazole (abbreviated as: TAZ), 1, 3-bis [5- (p-tert-butylphenyl) -1,3, 4-oxadiazol-2-yl ] benzene (abbreviated as: OXD-7), 9- [4- (5-phenyl-1, 3, 4-oxadiazol-2-yl) phenyl ] -9H-carbazole (abbreviated as: CO 11), 2' - (1, 3, 5-benzenetriyl) tris (1-phenyl-1H-benzimidazole) (abbreviated as: TPBI), 2- [3- (dibenzothiophen-4-yl) phenyl ] -1-phenyl-1H-benzimidazole (abbreviated as: mDBIm-II) and the like can be used.
As the heterocyclic compound having a diazine skeleton, for example, 2- [3- (dibenzothiophen-4-yl) phenyl ] dibenzo [ f, H ] quinoxaline (abbreviated as: 2 mDBTPDBq-II), 2- [3'- (dibenzothiophen-4-yl) biphenyl-3-yl ] dibenzo [ f, H ] quinoxaline (abbreviated as: 2 mDBTBPDBq-II), 2- [3' - (9H-carbazol-9-yl) biphenyl-3-yl ] dibenzo [ f, H ] quinoxaline (abbreviated as: 2 mCzBPDBq), 4, 6-bis [3- (phenanthr-9-yl) phenyl ] pyrimidine (abbreviated as: 4,6 mPnP2Pm), 4, 6-bis [3- (4-dibenzothiophenyl) phenyl ] pyrimidine (abbreviated as: 4,6 mDBTP2Pm-II), 4, 8-bis [3- (dibenzothiophen-4-yl) phenyl ] -benzo [ H ] quinazoline (abbreviated as: 4,8 mPqBqn) and the like can be used.
As the heterocyclic compound having a pyridine skeleton, for example, 3, 5-bis [3- (9H-carbazol-9-yl) phenyl ] pyridine (abbreviated as 35 DCzPPy), 1,3, 5-tris [3- (3-pyridyl) phenyl ] benzene (abbreviated as TmPyPB) and the like can be used.
As the heterocyclic compound having a triazine skeleton, for example, 2- [3' - (9, 9-dimethyl-9H-fluoren-2-yl) biphenyl-3-yl ] -4, 6-diphenyl-1, 3, 5-triazine (abbreviated as mFBPTzn), 2- [ (1, 1' -biphenyl) -4-yl ] -4-phenyl-6- [9,9' -spirodi (9H-fluoren) -2-yl ] -1,3, 5-triazine (abbreviated as BP-SFTzn), 2- {3- [3- (benzo [ b ] naphtho [1,2-d ] furan-8-yl) phenyl ] phenyl } -4, 6-diphenyl-1, 3, 5-triazine (abbreviated as mBnfBPTzn), 2- {3- [3- (benzo [ b ] naphtho [1,2-d ] furan-6-yl) phenyl ] phenyl } -4, 6-diphenyl-1, 3, 5-triazine (abbreviated as mBnfBPTzn-02) and the like can be used.
[ Material having an anthracene skeleton ]
An organic compound having an anthracene skeleton may be used for the layer 113. In particular, an organic compound having both an anthracene skeleton and a heterocyclic skeleton can be suitably used.
For example, an organic compound having both an anthracene skeleton and a nitrogen-containing five-membered ring skeleton can be used. In addition, an organic compound having both a nitrogen-containing five-membered ring skeleton and an anthracene skeleton, each containing two hetero atoms in the ring, can be used. Specifically, a pyrazole ring, an imidazole ring, an oxazole ring, a thiazole ring, or the like can be suitably used for the heterocyclic skeleton.
For example, an organic compound having both an anthracene skeleton and a nitrogen-containing six-membered ring skeleton can be used. In addition, an organic compound having both a nitrogen-containing six-membered ring skeleton and an anthracene skeleton, each containing two hetero atoms in the ring, can be used. Specifically, a pyrazine ring, a pyridine ring, a pyridazine ring, or the like can be suitably used for the heterocyclic skeleton.
[ structural example of Mixed Material ]
In addition, a material mixed with a plurality of substances may be used for the layer 113. Specifically, a mixed material containing an alkali metal, an alkali metal compound, or an alkali metal complex and a substance having electron-transporting property can be used for the layer 113. Note that the HOMO level of a material having electron-transporting property is more preferably-6.0 eV or more.
In addition, the hybrid material may be suitable for use in layer 113 in combination with the structure in which the composite material is used in layer 104. For example, a composite material of a substance having an acceptor property and a material having a hole-transporting property may be used for the layer 104. Specifically, a composite material of a substance having an acceptor property and a substance having a deep HOMO level HM1 of-5.7 eV or more and-5.4 eV or less may be used for the layer 104 (see fig. 2C). In particular, the composite material may be combined with the structure for layer 104 while the hybrid material is suitable for layer 113. Thereby, the reliability of the light emitting device can be improved.
In addition, a structure in which the mixed material is used for the layer 113 and the above-described composite material is used for the layer 104 and a structure in which a material having hole-transporting property is used for the layer 112 are appropriately used in combination. For example, a substance having a HOMO level HM2 in a range of-0.2 eV or more and 0eV or less with respect to the above-described deep HOMO level HM1 may be used for the layer 112 (see fig. 2C). Thereby, the reliability of the light emitting device can be improved. Note that in this specification and the like, the above-described light-emitting device is sometimes referred to as a Recombination-Site Tailoring Injection structure (a reinsti structure).
The alkali metal, alkali metal compound, or alkali metal complex is preferably present in such a manner that there is a concentration difference (including the case where the concentration difference is 0) in the thickness direction of the layer 113.
For example, a metal complex having an 8-hydroxyquinoline structure can be used. In addition, methyl substituents of metal complexes having an 8-hydroxyquinoline structure (for example, 2-methyl substituents or 5-methyl substituents) and the like can also be used.
As the metal complex having an 8-hydroxyquinoline structure, 8-hydroxyquinoline-lithium (abbreviated as Liq), 8-hydroxyquinoline-sodium (abbreviated as Naq) and the like can be used. In particular, among the monovalent metal ion complexes, lithium complexes are preferably used, and Liq is more preferably used.
Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification.
Embodiment 3
In this embodiment mode, a structure of a light emitting device 150 according to an embodiment of the present invention will be described with reference to fig. 1A.
< structural example of light-emitting device 150 >
The light emitting device 150 described in this embodiment mode includes an electrode 101, an electrode 102, a cell 103, and a layer 104. The electrode 102 has a region overlapping with the electrode 101, and the cell 103 has a region sandwiched between the electrode 101 and the electrode 102. In addition, the layer 104 has a region sandwiched between the electrode 101 and the cell 103. In addition, for example, the configuration described in embodiment mode 2 can be used for the unit 103.
< structural example of electrode 101 >
For example, a conductive material may be used for the electrode 101. Specifically, a metal, an alloy, a conductive compound, a mixture thereof, or the like may be used for the electrode 101. For example, a material having a work function of 4.0eV or more can be suitably used.
For example, indium Tin Oxide (ITO), indium Tin Oxide (ITSO) containing silicon or silicon Oxide, indium zinc Oxide (ITO), indium Oxide containing tungsten Oxide and zinc Oxide (IWZO), or the like can be used.
For example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or a nitride of a metal material (for example, titanium nitride) may be used. In addition, graphene may be used.
Structural example of layer 104
For example, a material having hole injection property may be used for the layer 104. In addition, the layer 104 may be referred to as a hole injection layer.
Specifically, a substance having acceptors can be used for the layer 104. Alternatively, a composite material of a substance having an acceptor property and a material having a hole-transporting property may be used for the layer 104. Thus, holes can be easily injected from the electrode 101, for example. In addition, the driving voltage of the light emitting device can be reduced.
[ substance having receptivity ]
An organic compound and an inorganic compound can be used as the substance having acceptors. The substance having an acceptor property can extract electrons from an adjacent hole-transporting layer or a material having a hole-transporting property by applying an electric field.
For example, a compound having an electron withdrawing group (a halogen group or a cyano group) can be used as a substance having an acceptor property. In addition, the organic compound having a receptor property can be easily formed by vapor deposition. Therefore, the productivity of the light emitting device can be improved.
Specifically, 7, 8-tetracyano-2, 3,5, 6-tetrafluoroquinone dimethane (abbreviated as F) 4 -TCNQ), chloranil, 2,3,6,7, 10, 11-hexacyanogen-1,4,5,8,9, 12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7, 8-hexafluorotetracyano (hexafluoroethane) -naphthoquinone dimethane (abbreviation: F6-TCNNQ), 2- (7-dicyanomethylene-1,3,4,5,6,8,9, 10-octafluoro-7H-pyrene-2-ylidene) malononitrile, and the like.
In particular, compounds in which an electron withdrawing group such as HAT-CN is bonded to a condensed aromatic ring having a plurality of hetero atoms are thermally stable, and are therefore preferable.
In addition, the [3] decenyl derivative comprising an electron withdrawing group (particularly, a halogen group such as a fluoro group or a cyano group) is very high in electron accepting property, and is therefore preferable.
Specifically, α ', α "-1,2, 3-cyclopropanetrimethylene tris [ 4-cyano-2, 3,5, 6-tetrafluorobenzyl cyanide ], α ', α" -1,2, 3-cyclopropanetrimethylene tris [2, 6-dichloro-3, 5-difluoro-4- (trifluoromethyl) benzyl cyanide ], α ', α "-1,2, 3-cyclopropanetrimethylene tris [2,3,4,5, 6-pentafluorophenyl acetonitrile ], and the like can be used.
In addition, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, or the like can be used for a substance having a receptor property.
In addition, phthalocyanine (abbreviated as H) 2 Pc) or phthalocyanine complexes such as copper phthalocyanine (CuPc) and the like; compounds having an aromatic amine skeleton, e.g. 4,4' -bis [ N- (4-diphenylaminophenyl) -N-phenylamino ]]Biphenyl (DPAB for short), N' -bis {4- [ bis (3-methylphenyl) amino group]Phenyl } -N, N ' -diphenyl- (1, 1' -biphenyl) -4,4' -diamine (abbreviated as DNTPD), and the like.
In addition, a polymer such as poly (3, 4-ethylenedioxythiophene)/poly (styrenesulfonic acid) (PEDOT/PSS) or the like can be used.
[ structural example 1 of composite Material ]
In addition, a material that is compounded with a plurality of substances can be used for the material having hole-injecting property. For example, a substance having an acceptor property and a material having a hole-transporting property can be used for the composite material. Thus, in addition to a material having a large work function, a material having a small work function can be used for the electrode 101. Alternatively, the material for the electrode 101 may be selected from a wide range of materials, independent of the work function.
For example, a compound having an aromatic amine skeleton, a carbazole derivative, an aromatic hydrocarbon having a vinyl group, a high molecular compound (oligomer, dendrimer, polymer, or the like), or the like can be used as a material having hole-transporting property in the composite material. In addition, the hole mobility may be 1×10 -6 cm 2 The material of/Vs or more is suitable for use as a material having hole-transporting property in the composite material.
In addition, a substance having a deep HOMO level can be suitably used for a material having hole-transporting property in the composite material. Specifically, the HOMO level is preferably-5.7 eV or more and-5.4 eV or less. Thus, holes can be easily injected into the cell 103. In addition, holes can be easily injected into the layer 112. In addition, the reliability of the light emitting device can be improved.
As the compound having an aromatic amine skeleton, for example, N ' -bis (p-tolyl) -N, N ' -diphenyl-p-phenylenediamine (abbreviated as DTDPPA), 4' -bis [ N- (4-diphenylaminophenyl) -N-phenylamino ] biphenyl (abbreviated as DPAB), N ' -bis {4- [ bis (3-methylphenyl) amino ] phenyl } -N, N ' -diphenyl- (1, 1' -biphenyl) -4,4' -diamine (abbreviated as DNTPD), 1,3, 5-tris [ N- (4-diphenylaminophenyl) -N-phenylamino ] benzene (abbreviated as DPA 3B) and the like can be used.
As the carbazole derivative, for example, 3- [ N- (9-phenylcarbazol-3-yl) -N-phenylamino ] -9-phenylcarbazole (abbreviated as: PCzPCA 1), 3, 6-bis [ N- (9-phenylcarbazol-3-yl) -N-phenylamino ] -9-phenylcarbazole (abbreviated as: PCzPCA 2), 3- [ N- (1-naphthyl) -N- (9-phenylcarbazol-3-yl) amino ] -9-phenylcarbazole (abbreviated as: PCzPCN 1), 4' -bis (N-carbazolyl) biphenyl (abbreviated as: CBP), 1,3, 5-tris [4- (N-carbazolyl) phenyl ] benzene (abbreviated as: TCPB), 9- [4- (10-phenyl-9-anthracenyl) phenyl ] -9H-carbazole (abbreviated as: czPA), 1, 4-bis [4- (N-carbazolyl) phenyl ] -2,3,5, 6-tetraphenyl, and the like can be used.
As the aromatic hydrocarbon, for example, 2-t-butyl-9, 10-bis (2-naphthyl) anthracene (abbreviated as: t-BuDNA), 2-t-butyl-9, 10-bis (1-naphthyl) anthracene (abbreviated as: DPPA), 2-t-butyl-9, 10-bis (4-phenylphenyl) anthracene (abbreviated as: t-BuDBA), 9, 10-bis (2-naphthyl) anthracene (abbreviated as: DNA), 9, 10-diphenyl anthracene (abbreviated as: DPAnth), 2-t-butyl anthracene (abbreviated as: t-BuAnth), 9, 10-bis (4-methyl-1-naphthyl) anthracene (abbreviated as: DMNA), 2-t-butyl-9, 10-bis [2- (1-naphthyl) phenyl ] anthracene, 2,3,6, 7-tetramethyl-9, 10-bis (1-naphthyl) anthracene, 2, 7-bis (4-naphthyl) anthracene, 10-bis (2-t-methyl-1-naphthyl) anthracene, 10-bis (2, 10-diphenyl) anthracene, 10 '-biphenyl-9, 10' -bis (9, 10-diphenyl) anthracene, 6-pentacenyl) phenyl ] -9,9' -dianthracene, anthracene, naphthacene, rubrene, perylene, 2,5,8, 11-tetra (t-butyl) perylene, pentacene, coronene, and the like.
As the aromatic hydrocarbon having a vinyl group, for example, 4' -bis (2, 2-diphenylvinyl) biphenyl (abbreviated as DPVBi), 9, 10-bis [4- (2, 2-diphenylvinyl) phenyl ] anthracene (abbreviated as DPVPA) and the like can be used.
As the polymer compound, for example, poly (N-vinylcarbazole) (abbreviated as PVK), poly (4-vinyltriphenylamine) (abbreviated as PVTPA), poly [ N- (4- { N '- [4- (4-diphenylamino) phenyl ] phenyl-N' -phenylamino } phenyl) methacrylamide ] (abbreviated as PTPDMA), poly [ N, N '-bis (4-butylphenyl) -N, N' -bis (phenyl) benzidine ] (abbreviated as Poly-TPD) and the like can be used.
In addition, for example, a substance having any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton can be suitably used as a material having hole-transporting property in the composite material. In addition, a substance containing an aromatic amine having a substituent including a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine including a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to nitrogen of an amine through an arylene group can be used. Note that when a substance including an N, N-bis (4-biphenyl) amino group is used, the reliability of the light-emitting device can be improved.
As these materials, for example, N- (4-biphenyl) -6, N-diphenylbenzo [ b ] naphtho [1,2-d ] furan-8-amine (abbreviation: bnfABP), N-bis (4-biphenyl) -6-phenylbenzo [ b ] naphtho [1,2-d ] furan-8-amine (abbreviation: BBABnf), 4' -bis (6-phenylbenzo [ b ] naphtho [1,2-d ] furan-8-yl) -4 "-phenyltriphenylamine (abbreviated as: bbnfbb 1 BP), N-bis (4-biphenyl) benzo [ b ] naphtho [1,2-d ] furan-6-amine (abbreviated as: BBABnf (6)), N-bis (4-biphenyl) benzo [ b ] naphtho [1,2-d ] furan-8-amine (abbreviated as: BBABnf (8)), N-bis (4-biphenyl) benzo [ b ] naphtho [2,3-d ] furan-4-amine (abbreviated as: BBABnf (II) (4)), N-bis [4- (dibenzofuran-4-yl) phenyl ] -4-amino-p-terphenyl (abbreviated as: DBfBB1 TP), N- [4- (dibenzothiophene-4-yl) phenyl ] -N-phenyl-4-benzidine (abbreviated as: thBA1 BP), 4- (2-naphthyl) -4',4 "-diphenyltriphenylamine (abbreviation: bbaβnb), 4- [4- (2-naphthyl) phenyl ] -4',4" -diphenyltriphenylamine (abbreviation: bbaβnbi), 4' -diphenyl-4 "- (6;1 ' -binaphthyl-2-yl) triphenylamine (abbreviation: bbaαnβnb), 4' -diphenyl-4" - (7;1 ' -binaphthyl-2-yl) triphenylamine (abbreviated as bbaαnβnb-03), 4' -diphenyl-4 "- (7-phenyl) naphthalen-2-yl triphenylamine (abbreviated as BBAP βnb-03), 4' -diphenyl-4" - (6;2 ' -binaphthyl-2-yl) triphenylamine (abbreviated as BBA (βn2) B), 4' -diphenyl-4 "- (7;2 ' -binaphthyl-2-yl) -triphenylamine (abbreviated as BBA (βn2) B-03), 4' -diphenyl-4" - (4;2 ' -binaphthyl-1-yl) triphenylamine (abbreviated as bbaβnαnb), 4,4' -diphenyl-4 "- (5;2 ' -binaphthyl-1-yl) triphenylamine (abbreviation: BBAβNαNB-02), 4- (4-biphenylyl) -4' - (2-naphthyl) -4" -phenyltriphenylamine (abbreviated as TPBiAβNB), 4- (3-biphenylyl) -4' - [4- (2-naphthyl) phenyl ] -4 "-phenyltriphenylamine (abbreviated as mTPBiAβNBi), 4- (4-biphenylyl) -4' - [4- (2-naphthyl) phenyl ] -4" -phenyltriphenylamine (abbreviated as TPBiAβNBi), 4-phenyl-4 ' - (1-naphthyl) triphenylamine (abbreviated as αNBA1 BP), 4' -bis (1-naphthyl) triphenylamine (abbreviated as αNBB1 BP), 4' -diphenyl-4 "- [4' - (carbazol-9-yl) biphenyl-4-yl ] triphenylamine (abbreviated as YGTBI 1), 4' - [4- (3-phenyl-9H-carbazol-9-yl) phenyl ] tris (1, 1' -biphenyl-4-yl) triphenylamine (abbreviated as YGTBI1 BP) 02, 4- [4'- (carbazol-9-yl) biphenyl-4-yl ] -4' - (2-naphthyl) -4 "-phenyltriphenylamine (abbreviated as YGTBI beta NB), N- [4- (9-phenyl-9H-carbazol-3-yl) phenyl ] -N- [4- (1-naphthyl) phenyl ] -9,9 '-spirobis [ 9H-fluoren ] -2-amine (abbreviated as PCBNBSF), N-bis ([ 1,1' -biphenyl ] -4-yl) -9,9 '-spirobis [ 9H-fluoren ] -2-amine (abbreviated as BBASF), N-bis (1, 1' -biphenyl-4-yl) -9,9 '-spirobis [ 9H-fluoren ] -4-amine (abbreviated as BBASF (4)), N- (1, 1' -biphenyl-2-yl) -N- (9, 9-dimethyl-9H-fluoren-2-yl) -9,9 '-spirobis [ 9H-fluoren ] -4-amine (abbreviated as oFBiSF), N- (4-biphenyl) -N- (9, 9-dimethyl-9H-fluoren-2-yl) -9, 9H-fluoren ] -2-amine (abbreviated as BBASF), N-bis (1' -biphenyl-4-yl) -9H-fluoren ] -2-amine (abbreviated as Fr F), N- [4- (1-naphthyl) phenyl ] -N- [3- (6-phenyldibenzofuran-4-yl) phenyl ] -1-naphthylamine (abbreviated as mPDBBBBN), 4-phenyl-4 '- (9-phenylfluoren-9-yl) triphenylamine (abbreviated as BPAFLP), 4-phenyl-3' - (9-phenylfluoren-9-yl) triphenylamine (abbreviated as mBPAFLP), 4-phenyl-4 '- [4- (9-phenylfluoren-9-yl) phenyl ] triphenylamine (abbreviated as BPAFLBi), 4-phenyl-4' - (9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviated as PCBA1 BP), 4 '-diphenyl-4 "- (9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviated as PCBBi1 BP), 4- (1-naphthyl) -4' - (9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviated as PCBB), 4 '-di (1-naphthyl) -4' - (9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviated as PCBB), 4 '-di (1-naphthyl) -4' - (9-phenyl-9-H-carbazol-3-yl) triphenylamine (abbreviated as PCBB), N-phenyl-N- [4- (9-phenyl-9H-carbazol-3-yl) phenyl ] spiro-9, 9 '-bifluorene-2-amine (abbreviated as PCBASF), N- (1, 1' -biphenyl-4-yl) -N- [4- (9-phenyl-9H-carbazol-3-yl) phenyl ] -9, 9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBAF), N-bis (9, 9-dimethyl-9H-fluoren-2-yl) -9,9 '-spirobi-9H-fluoren-4-amine, N-bis (9, 9-dimethyl-9H-fluoren-2-yl) -9,9' -spirobi-9H-fluoren-3-amine, N-bis (9, 9-dimethyl-9H-fluoren-2-yl) -9,9 '-spirobi-9H-fluoren-2-amine, N-bis (9, 9-dimethyl-9H-fluoren-2-yl) -9,9' -spirobi-fluoren-2-amine, and the like.
[ structural example of composite Material 2]
For example, a composite material containing a substance having an acceptor property, a material having a hole-transporting property, and a fluoride of an alkali metal or a fluoride of an alkaline earth metal can be used as the material having a hole-injecting property. In particular, a composite material having an atomic ratio of fluorine atoms of 20% or more can be suitably used. Thus, the refractive index of the layer 111 can be reduced. In addition, a layer having a low refractive index may be formed inside the light emitting device. In addition, external quantum efficiency of the light emitting device can be improved.
Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification.
Embodiment 4
In this embodiment mode, a structure of a light emitting device 150 according to an embodiment of the present invention will be described with reference to fig. 1A.
< structural example of light-emitting device 150 >
The light emitting device 150 described in this embodiment mode includes an electrode 101, an electrode 102, a cell 103, and a layer 105. The electrode 102 has a region overlapping with the electrode 101, and the cell 103 has a region sandwiched between the electrode 101 and the electrode 102. In addition, the layer 105 has a region sandwiched between the cell 103 and the electrode 102. In addition, for example, the configuration described in embodiment mode 2 can be used for the unit 103.
< structural example of electrode 102 >
For example, a conductive material may be used for the electrode 102. Specifically, a metal, an alloy, a conductive compound, a mixture thereof, or the like may be used for the electrode 102. For example, a material having a work function smaller than that of the electrode 101 may be used for the electrode 102. Specifically, a material having a work function of 3.8eV or less may be used.
For example, an element belonging to group 1 of the periodic table, an element belonging to group 2 of the periodic table, a rare earth metal, and an alloy containing them can be used for the electrode 102.
Specifically, lithium (Li), cesium (Cs), etc., magnesium (Mg), calcium (Ca), strontium (Sr), etc., europium (Eu), ytterbium (Yb), etc., and alloys (MgAg, alLi) containing them may be used for the electrode 102.
Structural example of layer 105
For example, a material having electron-injecting property may be used for the layer 105. In addition, the layer 105 may be referred to as an electron injection layer.
Specifically, a substance having donor property can be used for the layer 105. Alternatively, a composite material of a substance having a donor property and a material having an electron-transporting property may be used for the layer 105. Alternatively, an electron compound may be used for the layer 105. Thus, electrons can be easily injected from the electrode 102, for example. Alternatively, a material having a larger work function may be used for the electrode 102 in addition to a material having a smaller work function. Alternatively, the material for the electrode 102 may be selected from a wide range of materials, independent of work function. Specifically, al, ag, ITO, indium oxide-tin oxide containing silicon or silicon oxide, or the like can be used for the electrode 102. In addition, the driving voltage of the light emitting device can be reduced.
[ substance having Donor ]
For example, an alkali metal, an alkaline earth metal, a rare earth metal, or a compound thereof (oxide, halide, carbonate, or the like) may be used as the substance having donor properties. In addition, an organic compound such as tetrathiatetracene (abbreviated as TTN), nickel-dicyanoxide, and nickel-decamethyidicyanoxide can be used as a substance having donor properties.
As the alkali metal compound (including oxides, halides, carbonates), lithium oxide, lithium fluoride (LiF), cesium fluoride (CsF), lithium carbonate, cesium carbonate, 8-hydroxyquinoline-lithium (abbreviated as "Liq"), and the like can be used.
As the alkaline earth metal compound (including oxides, halides, carbonates), calcium fluoride (CaF 2 ) Etc.
[ structural example 1 of composite Material ]
In addition, a material that is compounded with a plurality of substances may be used for the material having electron-injecting property. For example, a substance having a donor property and a material having an electron-transporting property can be used for the composite material.
For example, a metal complex or an organic compound having a pi-electron deficient heteroaromatic ring skeleton may be used as the material having electron transporting property in the composite material. For example, a material having electron-transporting property that can be used for the unit 103 may be used for the composite material.
[ structural example of composite Material 2]
In addition, fluoride of alkali metal in a microcrystalline state and a material having electron-transporting property can be used for the composite material. In addition, a fluoride of an alkaline earth metal in a microcrystalline state and a material having electron-transporting properties can be used for the composite material. In particular, a composite material containing 50wt% or more of a fluoride of an alkali metal or a fluoride of an alkaline earth metal can be suitably used. In addition, a composite material containing an organic compound having a bipyridine skeleton can be suitably used. Thus, the refractive index of layer 104 may be reduced. In addition, external quantum efficiency of the light emitting device can be improved.
[ electronic Compound ]
For example, a substance in which electrons are added to a mixed oxide of calcium and aluminum at a high concentration, or the like, can be used for a material having electron-injecting properties.
Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification.
Embodiment 5
In this embodiment mode, a structure of a light emitting device 150 according to an embodiment of the present invention will be described with reference to fig. 3A.
Fig. 3A is a cross-sectional view illustrating a structure of a light emitting device according to an embodiment of the present invention.
< structural example of light-emitting device 150 >
The light-emitting device 150 described in this embodiment mode includes an electrode 101, an electrode 102, a cell 103, and an intermediate layer 106 (see fig. 3A). The electrode 102 has a region overlapping with the electrode 101, and the cell 103 has a region sandwiched between the electrode 101 and the electrode 102. The intermediate layer 106 has a region sandwiched between the cell 103 and the electrode 102.
Structural example of intermediate layer 106
Intermediate layer 106 includes layer 106A and layer 106B. Layer 106B has a region sandwiched between layer 106A and electrode 102.
Structural example of layer 106A
For example, a material having electron-transporting property may be used for the layer 106A. In addition, layer 106A may be referred to as an electronic relay layer. By using the layer 106A, a layer in contact with the anode side of the layer 106A can be separated from a layer in contact with the cathode side of the layer 106A. In addition, interaction between the layer in contact with the anode side of layer 106A and the layer in contact with the cathode side of layer 106A can be reduced. Thus, electrons can be smoothly supplied to the layer in contact with the anode side of the layer 106A.
A substance whose LUMO energy level is between that of a substance having an acceptor property in a layer in contact with the anode side of the layer 106A and that of a substance in a layer in contact with the cathode side of the layer 106A can be suitably used for the layer 106A.
For example, a material having a LUMO level in a range of-5.0 eV or more, preferably-5.0 eV or more and-3.0 eV or less can be used for the layer 106A.
Specifically, a phthalocyanine-based material can be used for the layer 106A. In addition, a metal complex having a metal-oxygen bond and an aromatic ligand may be used for the layer 106A.
Structural example of layer 106B
For example, a material which can supply electrons to the anode side and holes to the cathode side by applying a voltage can be used for the layer 106B. Specifically, electrons may be supplied to the cell 103 arranged on the anode side. In addition, the layer 106B may be referred to as a charge generation layer.
Specifically, a material having hole injection property that can be used for the layer 104 can be used for the layer 106B. For example, a composite material may be used for layer 106B. For example, a laminate film in which a film containing the composite material and a film containing a material having hole-transporting property are laminated may be used for the layer 106B.
Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification.
Embodiment 6
In this embodiment mode, a structure of a light emitting device 150 according to an embodiment of the present invention will be described with reference to fig. 3B.
Fig. 3B is a sectional view illustrating the structure of a light emitting device according to an embodiment of the present invention, which has a structure different from that shown in fig. 3A.
< structural example of light-emitting device 150 >
The light-emitting device 150 described in this embodiment mode includes the electrode 101, the electrode 102, the cell 103, the intermediate layer 106, and the cell 103 (12) (see fig. 3B). The electrode 102 has a region overlapping with the electrode 101, the cell 103 has a region sandwiched between the electrode 101 and the electrode 102, and the intermediate layer 106 has a region sandwiched between the cell 103 and the electrode 102. In addition, the cell 103 (12) has a region sandwiched between the intermediate layer 106 and the electrode 102, and the cell 103 (12) has a function of emitting the light EL1 (2).
In addition, a structure including the intermediate layer 106 and a plurality of cells is sometimes referred to as a stacked light-emitting device or a tandem light-emitting device. Therefore, high-luminance light emission can be obtained while keeping the current density low. In addition, the reliability can be improved. Further, the driving voltage at the time of comparison at the same luminance can be reduced. Further, power consumption can be suppressed.
Structural example of element 103 (12)
The structures available for the unit 103 may be used for the unit 103 (12). In other words, the light emitting device 150 includes a plurality of stacked units. Note that the plurality of stacked units is not limited to two units, and three or more units may be stacked.
The same structure as that of the unit 103 can be used for the unit 103 (12). In addition, a different structure from that of the unit 103 may be used for the unit 103 (12).
For example, a structure of a light emission color different from that of the unit 103 may be used for the unit 103 (12). Specifically, the red and green light emitting units 103 and the blue light emitting units 103 (12) may be used. Thus, a light emitting device that emits light of a desired color can be provided. For example, a light emitting device emitting white light may be provided.
Structural example of intermediate layer 106
The intermediate layer 106 has a function of supplying electrons to one of the cell 103 and the cell 103 (12) and supplying holes to the other thereof. For example, the intermediate layer 106 described in embodiment 5 can be used.
< method for manufacturing light-emitting device 150 >
For example, the layers of the electrode 101, the electrode 102, the cell 103, the intermediate layer 106, and the cell 103 (12) may be formed by a dry method, a wet method, a vapor deposition method, a droplet discharge method, a coating method, a printing method, or the like. In addition, each constituent element may be formed by a different method.
Specifically, the light emitting device 150 can be manufactured using a vacuum evaporation device, an inkjet device, a coating device such as a spin coater or the like, a gravure printing device, an offset printing device, a screen printing device, or the like.
The electrode may be formed by, for example, a wet method or a sol-gel method using a paste of a metal material. Further, an indium oxide-zinc oxide film may be formed by a sputtering method using a target material to which zinc oxide is added in an amount of 1wt% or more and 20wt% or less relative to indium oxide. Further, an indium oxide (IWZO) film containing tungsten oxide and zinc oxide can be formed by a sputtering method using a target material to which tungsten oxide of 0.5wt% or more and 5wt% or less and zinc oxide of 0.1wt% or more and 1wt% or less are added with respect to indium oxide.
Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification.
Embodiment 7
In this embodiment, the structure of a functional panel 700 according to an embodiment of the present invention will be described with reference to fig. 4A and 4B.
Fig. 4A is a sectional view illustrating the structure of a functional panel 700 according to an embodiment of the present invention, and fig. 4B is a sectional view illustrating the structure of the functional panel 700 according to an embodiment of the present invention, which is different from fig. 4A.
< structural example 1 of functional Panel 700 >
The functional panel 700 described in this embodiment includes the light emitting device 150 and the light emitting device 150 (2) (see fig. 4A). In addition, the functional panel 700 includes an insulating film 521.
The functional panel 700 includes an insulating film 528 (refer to fig. 4A). The insulating film 528 includes openings, one of which overlaps with the electrode 101 and the other of which overlaps with the electrode 101 (2).
< structural example 2 of functional Panel 700 >
The functional panel 700 includes, for example, an insulating film 573 (see fig. 4B). The insulating film 573 includes an insulating film 573A and an insulating film 573B, and the insulating film 573A has a region sandwiched between the insulating film 573B and the insulating film 521.
In addition, a groove is provided between the unit 103 (2) and the unit 103, and the unit 103 (2) has a side wall along the groove. In addition, the cell 103 also has sidewalls along the slot.
The insulating film 573A has a region in contact with the side wall of the cell 103 (2) and a region in contact with the side wall of the cell 103.
For example, the light emitting device described in embodiment modes 1 to 6 can be used as the light emitting device 150.
< structural example of light-emitting device 150 (2) >)
The light-emitting device 150 (2) described in this embodiment mode includes the electrode 101 (2), the electrode 102, and the cell 103 (2) (see fig. 4A). The electrode 102 has a region overlapping with the electrode 101 (2), and the cell 103 (2) has a region sandwiched between the electrode 101 (2) and the electrode 102.
The potential of the electrode 101 (2) may be the same as or different from the potential of the electrode 101. By supplying different potentials, the light emitting device 150 (2) can be driven under different conditions from the light emitting device 150. Note that a material usable for the electrode 101 may be used for the electrode 101 (2).
In addition, the light emitting device 150 (2) includes the layer 104 and the layer 105. Layer 104 has a region sandwiched between electrode 101 (2) and cell 103 (2), and layer 105 has a region sandwiched between cell 103 (2) and electrode 102. Note that a part of the structure of the light emitting device 150 may be used for a part of the structure of the light emitting device 150 (2). Thus, a part of the structure can be shared. Alternatively, the manufacturing process may be simplified.
< structural example of cell 103 (2) >)
The unit 103 (2) has a single-layer structure or a stacked-layer structure. The unit 103 (2) includes, for example, a layer 111 (2), a layer 112, and a layer 113 (see fig. 4A). The cell 103 (2) includes, for example, a layer 111 (2), a layer 112 (2), and a layer 113 (2) (see fig. 4B). Note that the layer 112 (2) has a structure usable for the layer 112, and the layer 113 (2) has a structure usable for the layer 113.
Layer 111 (2) has a region sandwiched between layer 112 and layer 113, layer 112 has a region sandwiched between electrode 101 (2) and layer 111 (2), and layer 113 has a region sandwiched between electrode 102 and layer 111 (2).
For example, a layer selected from a functional layer such as a light-emitting layer, a hole-transporting layer, an electron-transporting layer, and a carrier blocking layer may be used for the unit 103 (2). In addition, a layer selected from a functional layer such as a hole injection layer, an electron injection layer, an exciton blocking layer, and a charge generation layer may be used for the cell 103 (2).
Structural example 1> of layer 111 (2)
For example, a light-emitting material or a host material may be used for the layer 111 (2). In addition, the layer 111 (2) may be referred to as a light emitting layer. Note that the layer 111 (2) is preferably arranged in a region where holes and electrons are recombined. Thus, energy generated by carrier recombination can be efficiently emitted as light. In addition, the layer 111 (2) is preferably disposed away from the metal used for the electrode or the like. Therefore, quenching of the metal used for the electrode and the like can be suppressed.
For example, a light-emitting material different from that used for the layer 111 may be used for the layer 111 (2). Specifically, luminescent materials having different luminescent colors may be used for the layer 111 (2). Thereby, light emitting devices having colors different from each other can be configured. In addition, additive color mixing can be performed using a plurality of light emitting devices having different hues. In addition, the color of the hue that each light emitting device cannot display can be expressed.
For example, a light emitting device that emits blue light, a light emitting device that emits green light, and a light emitting device that emits red light may be arranged in the functional panel. Alternatively, a light emitting device that emits white light, a light emitting device that emits yellow light, and a light emitting device that emits infrared light may be arranged on the functional panel.
Structural example 2> of layer 111 (2)
For example, a fluorescent light-emitting substance, a phosphorescent light-emitting substance, or a substance exhibiting thermally activated delayed fluorescence (also referred to as TADF material) may be used for the luminescent material. This allows energy generated by recombination of carriers to be emitted from the light-emitting material as light EL2 (see fig. 4A).
[ fluorescent substance ]
A fluorescent light-emitting substance may be used for the layer 111 (2). For example, the following fluorescent light-emitting substance can be used for the layer 111 (2). Note that the fluorescent light-emitting substance is not limited thereto, and various known fluorescent light-emitting substances may be used for the layer 111 (2).
In particular, 5, 6-bis [4- (10-phenyl-9-anthryl) phenyl ] can be used]-2,2 '-bipyridine (PAP 2 BPy), 5, 6-bis [4' - (10-phenyl-9-anthryl) biphenyl-4-yl]-2,2' -bipyridine (abbreviated as PAPP2 BPy), N ' -diphenyl-N, N ' -bis [4- (9-phenyl-9H-fluoren-9-yl) phenyl ]]Pyrene-1, 6-diamine (1, 6 FLPAPRN), N '-bis (3-methylphenyl) -N, N' -bis [3- (9-phenyl-9H-fluoren-9-yl) phenyl ]]Pyrene-1, 6-diamine (1, 6 mMemFLPAPRN), N' -bis [4- (9H-carbazol-9-yl) phenyl ]]-N, N '-diphenylstilbene-4, 4' -diamine (abbreviated as YGA 2S), 4- (9H-carbazol-9-yl) -4'- (10-phenyl-9-anthryl) triphenylamine (abbreviated as YGAPA), 4- (9H-carbazol-9-yl) -4' - (9, 10-diphenyl-2-anthryl) triphenylamine (abbreviated as 2 YGAPA), N, 9-diphenyl-N- [4- (10-phenyl-9-anthryl) phenyl]-9H-carbazol-3-amine (abbreviated PCAPA), perylene, 2,5,8, 11-tetra (t-butyl) perylene (abbreviated TBP), 4- (10-phenyl-9-anthryl) -4'- (9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviated PCAPA), N' - (2-t-butylanthracene-9, 10-diylbis-4, 1-phenylene) bis [ N, N ', N' -triphenyl-1, 4-phenylenediamine](abbreviated as DPABPA), N, 9-diphenyl-N- [4- (9, 10-diphenyl-2-anthryl) phenyl group ]-9H-carbazol-3-amine (abbreviated as 2 PCAPPA), N- [4- (9, 10-diphenyl-2-anthryl) phenyl]-N, N ', N ' -triphenyll-1, 4-phenylenediamine (abbreviated as 2 DPAPPA), N, N, N ', N ', N ", N", N ' "-octaphenyldibenzo [ g, p ]]-2,7, 10, 15-tetramine (DBC 1 for short), coumarin 30, N- (9, 10-diphenyl-2-anthryl) -N, 9-diphenyl-9H-carbazole-3-amine (2 PCAPA for short), N- [9, 10-bis (1, 1' -biphenyl-2-yl) -2-anthryl]-N, 9-diphenyl-9H-carbazole-3-amine (abbreviated as 2 PCABPhA), N- (9, 10-diphenyl-)2-anthryl) -N, N' -triphenyl-1, 4-phenylenediamine (abbreviation: 2 DPAPA), N- [9, 10-bis (1, 1' -biphenyl-2-yl) -2-anthryl]-N, N ', N ' -triphenyll-1, 4-phenylenediamine (abbreviated as: 2 DPABPhA), 9, 10-bis (1, 1' -biphenyl-2-yl) -N- [4- (9H-carbazol-9-yl) phenyl ]]-N-phenylanthracene-2-amine (abbreviated as 2 YGABAPhA), N, 9-triphenylanthracene-9-amine (abbreviated as DPhAPHA), coumarin 545T, N, N '-diphenylquinacridone (abbreviated as DPqd), rubrene, 5, 12-bis (1, 1' -biphenyl-4-yl) -6, 11-diphenyltetracene (abbreviated as BPT), 2- (2- {2- [4- (dimethylamino) phenyl ]]Vinyl } -6-methyl-4H-pyran-4-ylidene) malononitrile (abbreviation: DCM 1), 2- { 2-methyl-6- [2- (2, 3,6, 7-tetrahydro-1H, 5H-benzo [ ij ] ]Quinolizin-9-yl) vinyl]-4H-pyran-4-ylidene } malononitrile (abbreviated as DCM 2), N, N, N ', N' -tetrakis (4-methylphenyl) acenaphthene-5, 11-diamine (abbreviated as p-mPHTD), 7, 14-diphenyl-N, N, N ', N' -tetrakis (4-methylphenyl) acenaphtho [1,2-a]Fluoranthene-3, 10-diamine (abbreviated as p-mPHIFD), 2- { 2-isopropyl-6- [2- (1, 7-tetramethyl-2, 3,6, 7-tetrahydro-1H, 5H-benzo [ ij ]]Quinolizin-9-yl) vinyl]-4H-pyran-4-ylidene } malononitrile (DCJTI for short), 2- { 2-tert-butyl-6- [2- (1, 7-tetramethyl-2, 3,6, 7-tetrahydro-1H, 5H-benzo [ ij ]]Quinolizin-9-yl) vinyl]-4H-pyran-4-ylidene } malononitrile (DCJTB for short), 2- (2, 6-bis {2- [4- (dimethylamino) phenyl }, 2-propanedinitrile]Vinyl } -4H-pyran-4-ylidene) malononitrile (abbreviation: bisDCM), 2- {2, 6-bis [2- (8-methoxy-1, 7-tetramethyl-2, 3,6, 7-tetrahydro-1 h,5 h-benzo [ ij ]]Quinolizin-9-yl) vinyl]-4H-pyran-4-ylidene } malononitrile (BisDCJTM for short), N' - (pyrene-1, 6-diyl) bis [ (6, N-diphenylbenzo [ b ]]Naphtho [1,2-d]Furan) -8-amine](abbreviated as 1,6 BnfAPrn-03), 3, 10-bis [ N- (9-phenyl-9H-carbazol-2-yl) -N-phenylamino ]]Naphtho [2,3-b;6,7-b' ]Bis-benzofuran (3, 10PCA2Nbf (IV) -02), 3, 10-bis [ N- (dibenzofuran-3-yl) -N-phenylamino]Naphtho [2,3-b;6,7-b']Bis-benzofurans (abbreviated as: 3, 10FrA2Nbf (IV) -02), and the like.
In particular, a condensed aromatic diamine compound represented by a pyrenediamine compound such as 1,6flpaprn, 1,6 mmmemflpaprn, 1,6 bnfprn-03, etc. is preferable because it has high hole-trapping property and good luminous efficiency or reliability.
[ phosphorescent light-emitting substance ]
Phosphorescent light-emitting substances may be used for the layer 111 (2). For example, the following phosphorescent light-emitting substance can be used for the layer 111 (2). Note that the phosphorescent light-emitting substance is not limited thereto, and various known phosphorescent light-emitting substances may be used for the layer 111 (2).
For example, the following materials may be used for layer 111 (2): an organometallic iridium complex having a 4H-triazole skeleton, an organometallic iridium complex having a 1H-triazole skeleton, an organometallic iridium complex having an imidazole skeleton, an organometallic iridium complex having an electron-withdrawing group and having a phenylpyridine derivative as a ligand, an organometallic iridium complex having a pyrimidine skeleton, an organometallic iridium complex having a pyrazine skeleton, an organometallic iridium complex having a pyridine skeleton, a rare earth metal complex, a platinum complex, or the like.
[ phosphorescent light-emitting substance (blue) ]
As the organometallic iridium complex having a 4H-triazole skeleton, or the like, tris {2- [5- (2-methylphenyl) -4- (2, 6-dimethylphenyl) -4H-1,2, 4-triazol-3-yl- κN may be used 2 ]Phenyl-. Kappa.C } iridium (III) (abbreviated as: [ Ir (mpptz-dmp) ] 3 ]) Tris (5-methyl-3, 4-diphenyl-4H-1, 2, 4-triazole) iridium (III) (abbreviation: [ Ir (Mptz) 3 ]) Tris [4- (3-biphenyl) -5-isopropyl-3-phenyl-4H-1, 2, 4-triazole]Iridium (III) (abbreviated as: [ Ir (iPrtz-3 b) 3 ]) Etc.
As the organometallic iridium complex having a 1H-triazole skeleton, tris [ 3-methyl-1- (2-methylphenyl) -5-phenyl-1H-1, 2, 4-triazole or the like can be used]Iridium (III) (abbreviated as: [ Ir (Mptz 1-mp) ] 3 ]) Tris (1-methyl-5-phenyl-3-propyl-1H-1, 2, 4-triazole) iridium (III) (abbreviation: [ Ir (Prptz 1-Me) 3 ]) Etc.
As the organometallic iridium complex having an imidazole skeleton, etc., fac-tris [1- (2, 6-diisopropylphenyl) -2-phenyl-1H-imidazole can be used]Iridium (III) (abbreviated: [ Ir (iPrmi) ] 3 ]) Tris [3- (2, 6-dimethylphenyl) -7-methylimidazole [1,2-f ]]Phenanthridine root (phenanthrinator)]Iridium (III) (abbreviated as: [ Ir (dmpimpt-Me) ] 3 ]) Etc.
As an organometallic iridium complex or the like having a phenylpyridine derivative having an electron-withdrawing group as a ligand, bis [2- (4 ',6' -difluorophenyl) pyridine-N, C can be used 2’ ]Iridium (III) tetrakis (1-pyrazole) borate (FIr 6 for short), bis [2- (4 ',6' -difluorophenyl) pyridinato-N, C 2’ ]Iridium (III) picolinate (FIrpic), bis {2- [3',5' -bis (trifluoromethyl) phenyl ]]pyridine-N, C 2’ Iridium (III) picolinate (abbreviation: [ Ir (CF) 3 ppy) 2 (pic)]) Bis [2- (4 ',6' -difluorophenyl) pyridino-N, C 2’ ]Iridium (III) acetylacetonate (abbreviated as FIracac) and the like.
The above-mentioned substance is a compound that emits blue phosphorescence, and is a compound having a peak of an emission wavelength at 440nm to 520 nm.
[ phosphorescent light-emitting substance (Green) ]
As an organometallic iridium complex having a pyrimidine skeleton, tris (4-methyl-6-phenylpyrimidinate) iridium (III) (abbreviated as: [ Ir (mppm)) 3 ]) Tris (4-tert-butyl-6-phenylpyrimidinyl) iridium (III) (abbreviation: [ Ir (tBuppm) 3 ]) (acetylacetonato) bis (6-methyl-4-phenylpyrimidino) iridium (III) (abbreviation: [ Ir (mppm) 2 (acac)]) (acetylacetonato) bis (6-t-butyl-4-phenylpyrimidino) iridium (III) (abbreviation: [ Ir (tBuppm) 2 (acac)]) (acetylacetonato) bis [6- (2-norbornyl) -4-phenylpyrimidinyl ]]Iridium (III) (abbreviated as: [ Ir (nbppm) ] 2 (acac)]) (acetylacetonato) bis [ 5-methyl-6- (2-methylphenyl) -4-phenylpyrimidinyl ]]Iridium (III) (abbreviated: [ Ir (mpmppm)) 2 (acac)]) (acetylacetonate) bis (4, 6-diphenylpyrimidinyl) iridium (III) (abbreviation: [ Ir (dppm) 2 (acac)]) Etc.
As an organometallic iridium complex having a pyrazine skeleton, bis (3, 5-dimethyl-2-phenylpyrazinyl) iridium (III) (abbreviated as: [ Ir (mppr-Me)) 2 (acac)]) (acetylacetonato) bis (5-isopropyl-3-methyl-2-phenylpyrazinyl) iridium (III) (abbreviation: [ Ir (mppr-iPr) 2 (acac)]) Etc.
As the organometallic iridium complex having a pyridine skeleton, etc., tris (2-phenylpyridyl-N, C may be used 2 ' iridium (III) (abbreviation: [ Ir (ppy) 3 ]) Bis (2-phenylpyridyl-N, C) 2 ' iridium (III) acetylacetonate (abbreviation: [ Ir (ppy) 2 (acac)]) Bis (benzo [ h ]]Quinoline) iridium (III) acetylacetonate (abbreviation: [ Ir (bzq) 2 (acac)]) Tris (benzo [ h ]]Quinoline) iridium (III) (abbreviation: [ Ir (bzq) 3 ]) Tris (2-phenylquinoline-N, C 2 ']Iridium (III) (abbreviated as: [ Ir (pq) ] 3 ]) Bis (2-phenylquinoline-N, C) 2 ' iridium (III) acetylacetonate (abbreviation: [ Ir (pq) 2 (acac)])、[2-d 3 -methyl-8- (2-pyridinyl- κN) benzofuro [2,3-b]Pyridine-kappa C]Bis [2- (5-d) 3 -methyl-2-pyridinyl- κn 2 ) Phenyl-kappa C]Iridium (III) (abbreviated as: [ Ir (5 mppy-d) 3 ) 2 (mbfpypy-d 3 )])、[2-d 3 -methyl- (2-pyridinyl- κN) benzofuro [2,3-b]Pyridine-kappa C]Bis [2- (2-pyridinyl- κN) phenyl- κC]Iridium (III) (abbreviated as: [ Ir (ppy)) 2 (mbfpypy-d 3 )]) Etc.
As the rare earth metal complex, there may be mentioned tris (acetylacetonate) (Shan Feige) terbium (III) (abbreviated as: [ Tb (acac) ] 3 (Phen)]) Etc.
The above-mentioned substances are mainly compounds that emit green phosphorescence and have peaks of light emission wavelength at 500nm to 600 nm. In addition, an organometallic iridium complex having a pyrimidine skeleton is particularly preferable because it has particularly excellent reliability or luminous efficiency.
[ phosphorescent light-emitting substance (Red) ]
As the organometallic iridium complex having a pyrimidine skeleton, etc., bis [4, 6-bis (3-methylphenyl) pyrimidine radical (diisobutyrylmethane radical) ] may be used]Iridium (III) (abbreviated as: [ Ir (5 mdppm) 2 (dibm) ]]) Bis [4, 6-bis (3-methylphenyl) pyrimidinyl) (dipivaloylmethane) iridium (III) (abbreviation: [ Ir (5 mdppm) 2 (dpm)]) Bis [4, 6-di (naphthalen-1-yl) pyrimidinyl]Ir (d 1 npm) iridium (III) (abbreviated as: [ Ir (d 1) npm) 2 (dpm)]) Etc.
As an organometallic iridium complex having a pyrazine skeleton or the like, (acetylacetonato) bis (2, 3, 5-triphenylpyrazino) iridium (III) (abbreviated as: [ Ir (tppr)) 2 (acac)]) Bis (2, 3, 5-tris)Phenylpyrazinyl) (dipivaloylmethane) iridium (III) (abbreviation: [ Ir (tppr) 2 (dpm)]) (acetylacetonate) bis [2, 3-bis (4-fluorophenyl) quinoxaline (quinoxalato) ]Iridium (III) (abbreviated: [ Ir (Fdpq)) 2 (acac)]) Etc.
As the organometallic iridium complex having a pyridine skeleton, etc., tris (1-phenylisoquinoline-N, C may be used 2’ ) Iridium (III) (abbreviation: [ Ir (piq) 3 ]) Bis (1-phenylisoquinoline-N, C 2’ ) Iridium (III) acetylacetonate (abbreviation: [ Ir (piq) 2 (acac)]) Etc.
As rare earth metal complexes, there may be mentioned tris (1, 3-diphenyl-1, 3-propanedione) (Shan Feige in) europium (III) (abbreviated as: [ Eu (DBM) ] 3 (Phen)]) Tris [1- (2-thenoyl) -3, 3-trifluoroacetone](Shan Feige) europium (III) (abbreviated as [ Eu (TTA) 3 (Phen))]) Etc.
As the platinum complex, 2,3,7,8, 12, 13, 17, 18-octaethyl-21H, 23H-porphyrin platinum (II) (abbreviated as PtOEP) and the like can be used.
The above-mentioned substance is a compound that emits red phosphorescence and has a luminescence peak at 600nm to 700 nm. In addition, an organometallic iridium complex having a pyrazine skeleton can obtain red light emission having chromaticity which can be suitably used for a display device.
[ substance exhibiting delayed fluorescence by Thermal Activation (TADF) ]
TADF material may be used for layer 111 (2). Since the difference between the S1 energy level and the T1 energy level in the TADF material is small, the triplet-excited-state intersystem crossing (up-conversion) can be converted into a singlet-excited state by a small amount of thermal energy. Thus, a singlet excited state can be efficiently generated from the triplet excited state. In addition, the triplet excited state can be converted into luminescence.
An Exciplex (Exciplex) in which two substances form an excited state has a function of a TADF material capable of converting triplet excitation energy into singlet excitation energy because the difference between the S1 energy level and the T1 energy level is extremely small.
Note that as an index of the T1 level, a phosphorescence spectrum observed at a low temperature (for example, 77K to 10K) may be used. Regarding the TADF material, it is preferable that when the wavelength energy of the extrapolated line obtained by the tail-end steering line at the shortest wavelength of the fluorescence spectrum is at the S1 level and the wavelength energy of the extrapolated line obtained by the tail-end steering line at the shortest wavelength of the phosphorescence spectrum is at the T1 level, the difference between the S1 level and the T1 level is 0.3eV or less, more preferably 0.2eV or less.
Further, when a TADF material is used as the light-emitting substance, the S1 energy level of the host material is preferably higher than that of the TADF material. Further, the T1 energy level of the host material is preferably higher than the T1 energy level of the TADF material.
For example, the TADF material described in embodiment 1, which can be used as a host material, can be used as a luminescent material.
Structural example 3> of layer 111 (2)
A material having carrier transport property may be used for the host material. For example, a material having a hole-transporting property, a material having an electron-transporting property, a substance exhibiting thermally activated delayed fluorescence, a material having an anthracene skeleton, a mixed material, or the like can be used as the host material. Note that a material having a band gap larger than that of the light-emitting material in the layer 111 (2) is preferably used for the host material. Therefore, energy transfer from excitons to the host material generated by the layer 111 (2) can be suppressed.
[ Material having hole-transporting property ]
Hole mobility can be set to 1×10 -6 cm 2 The material of/Vs or more is used for a material having hole-transporting property.
For example, a material having hole-transporting property that can be used for the layer 112 can be used for the layer 111 (2). Specifically, a material having hole-transporting property that can be used for the hole-transporting layer can be used for the layer 111 (2).
[ Material having Electron-transporting Property ]
For example, a material having electron-transporting property that can be used for the layer 113 can be used for the layer 111 (2). Specifically, a material having electron-transporting property that can be used for the electron-transporting layer can be used for the layer 111 (2).
[ Material having an anthracene skeleton ]
An organic compound having an anthracene skeleton can be used for the host material. In particular, when a fluorescent light-emitting substance is used as the light-emitting substance, an organic compound having an anthracene skeleton is suitable. Thus, a light-emitting device having excellent light-emitting efficiency and durability can be realized.
As the organic compound having an anthracene skeleton, an organic compound having a diphenylanthracene skeleton, particularly a 9, 10-diphenylanthracene skeleton, is preferable because it is chemically stable. In addition, when the host material has a carbazole skeleton, hole injection and transport properties are improved, so that it is preferable. In particular, when the host material has a dibenzocarbazole skeleton, the HOMO level thereof is about 0.1eV shallower than carbazole, and not only hole injection is easy but also hole transport property and heat resistance are improved, which is preferable. Note that from the viewpoint of hole injection and transport properties described above, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton.
Therefore, a substance having a 9, 10-diphenylanthracene skeleton and a carbazole skeleton, a substance having a 9, 10-diphenylanthracene skeleton and a benzocarbazole skeleton, and a substance having a 9, 10-diphenylanthracene skeleton and a dibenzocarbazole skeleton are preferably used as the host material.
For example, 6- [3- (9, 10-diphenyl-2-anthracene) phenyl ] -benzo [ b ] naphtho [1,2-d ] furan (abbreviated as: 2 mBnfPPA), 9-phenyl-10- {4- (9-phenyl-9H-fluoren-9-yl) biphenyl-4' -yl } anthracene (abbreviated as: FLPPA), 9- (1-naphthyl) -10- [4- (2-naphthyl) phenyl ] anthracene (abbreviated as: αN-. Beta. NPAnth), 9-phenyl-3- [4- (10-phenyl-9-anthracenyl) phenyl ] -9H-carbazole (abbreviated as: PCzPA), 9- [4- (10-phenyl-9-anthracenyl) phenyl ] -9H-carbazole (abbreviated as: czPA), 7- [4- (10-phenyl-9-anthracenyl) phenyl ] -7H-dibenzo [ c, g ] carbazole (abbreviated as: cgCzPA), 3- [4- (1-naphthyl) -phenyl ] -9-phenyl-9H-carbazole (abbreviated as: PCPN), and the like can be used.
In particular CzPA, cgDBCzPA, 2mBnfPPA, PCzPA exhibit very good properties.
[ structural example of Mixed Material 1]
In addition, a material in which a plurality of substances are mixed may be used for the host material. For example, a material having an electron-transporting property and a material having a hole-transporting property may be mixed for the mixed material. The weight ratio of the hole-transporting material to the electron-transporting material in the mixed material may be (hole-transporting material/electron-transporting material) = (1/19) or more and (19/1) or less. This makes it possible to easily adjust the carrier transport property of the layer 111 (2). In addition, the control of the composite region can be performed easily.
[ structural example of Mixed Material 2]
A material mixed with a phosphorescent light-emitting substance may be used for the host material. Phosphorescent light-emitting substances can be used as energy donors for supplying excitation energy to fluorescent light-emitting substances when fluorescent light-emitting substances are used as light-emitting substances.
In addition, a mixed material containing an exciplex-forming material may be used for the host material. For example, a material in which the emission spectrum of the formed exciplex overlaps with the wavelength of the absorption band on the lowest energy side of the light-emitting substance can be used for the host material. Therefore, energy transfer can be made smooth, thereby improving luminous efficiency. In addition, the driving voltage can be suppressed. By adopting such a structure, light emission of ExTET (Excilex-Triplet Energy Transfer: exciplex-triplet energy transfer) utilizing energy transfer from an Exciplex to a light-emitting substance (phosphorescent material) can be obtained efficiently.
Phosphorescent emitters may be used for at least one of the materials forming the exciplex. Thus, the intersystem crossing can be utilized. Alternatively, the triplet excitation energy can be efficiently converted into the singlet excitation energy.
The HOMO level of the material having hole-transporting property is preferably equal to or higher than the HOMO level of the material having electron-transporting property as a combination of materials forming the exciplex. Alternatively, the LUMO level of the material having hole-transporting property is preferably equal to or higher than the LUMO level of the material having electron-transporting property. Thus, an exciplex can be efficiently formed. The LUMO level and HOMO level of the material can be obtained from electrochemical characteristics (reduction potential and oxidation potential). Specifically, the reduction potential and the oxidation potential can be measured by Cyclic Voltammetry (CV) measurement.
Note that the formation of an exciplex can be confirmed by, for example, the following method: comparing the emission spectrum of a material having hole-transporting property, the emission spectrum of a material having electron-transporting property, and the emission spectrum of a mixed film obtained by mixing these materials, it is explained that an exciplex is formed when a phenomenon is observed in which the emission spectrum of the mixed film shifts to the long wavelength side (or has a new peak on the long wavelength side) than the emission spectrum of each material. Alternatively, when transient Photoluminescence (PL) of a material having hole-transporting property, transient PL of a material having electron-transporting property, and transient PL of a mixed film obtained by mixing these materials are compared, transient PL of the mixed film is observed to have a long lifetime component or a transient response such as a ratio of a delayed component being larger than the transient PL lifetime of each material, the formation of an exciplex is described. In addition, the above-described transient PL may be referred to as transient Electroluminescence (EL). In other words, the formation of an exciplex can be confirmed by observing the difference in transient response from the transient EL of a material having hole-transporting property, the transient EL of a material having electron-transporting property, and the transient EL of a mixed film of these materials.
Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification.
Embodiment 8
In this embodiment, a structure of a function panel 700 according to an embodiment of the present invention will be described with reference to fig. 5.
< structural example 1 of functional Panel 700 >
The functional panel 700 described in this embodiment includes the light emitting device 150 and the optical functional device 170 (see fig. 5A).
For example, the light emitting device described in embodiment modes 1 to 6 can be used as the light emitting device 150.
< structural example of optical functional device 170 >
The optical function device 170 described in this embodiment includes an electrode 101S, an electrode 102, and a cell 103S. The electrode 102 includes a region overlapping with the electrode 101S, and the cell 103S includes a region sandwiched between the electrode 101S and the electrode 102.
In addition, light functional device 170 includes layer 104 and layer 105. Layer 104 includes the region sandwiched between electrode 101S and cell 103S, and layer 105 includes the region sandwiched between cell 103S and electrode 102. Note that a partial structure of the light emitting device 150 may be used for a partial structure of the light functional device 170. Thus, the partial structure can be shared. In addition, the manufacturing process can be simplified.
< structural example 1 of cell 103S >
The unit 103S has a single-layer structure or a stacked-layer structure. For example, the cell 103S includes a layer 114, a layer 112, and a layer 113 (see fig. 5A).
Layer 114 includes a region sandwiched between layer 112 and layer 113, layer 112 includes a region sandwiched between electrode 101S and layer 114, and layer 113 includes a region sandwiched between electrode 102 and layer 114.
For example, a layer selected from functional layers such as a photoelectric conversion layer, a hole transport layer, an electron transport layer, and a carrier blocking layer may be used for the cell 103S. In addition, a layer selected from functional layers such as an exciton blocking layer and a charge generation layer may be used for the cell 103S.
The cell 103S absorbs the light hv, supplies electrons to one electrode and holes to the other electrode. For example, the unit 103S supplies holes to the electrode 101S and electrons to the electrode 102.
Structural example of layer 112
For example, a material having hole-transporting property may be used for the layer 112. In addition, the layer 112 may be referred to as a hole transport layer. For example, the structure described in embodiment mode 2 can be used for the layer 112.
Structural example of layer 113
For example, a material having electron-transporting property, a material having an anthracene skeleton, a mixed material, or the like can be used for the layer 113. For example, the structure described in embodiment mode 2 can be used for the layer 113.
Structural example 1 of layer 114
For example, an electron-accepting material and an electron-donating material may be used for the layer 114. Specifically, materials that can be used for the organic solar cell can be used for the layer 114. In addition, the layer 114 may be referred to as a photoelectric conversion layer. The layer 114 absorbs the light hv, supplying electrons to one electrode and holes to the other electrode. For example, the layer 114 supplies holes to the electrode 101S and electrons to the electrode 102.
[ examples of Electron-receiving materials ]
For example, fullerene derivatives, non-fullerene electron acceptors, and the like can be used for the electron accepting material.
As the electron-receiving material, C can be used 60 Fullerene, C 70 Fullerene, [6,6 ]]-phenyl-C 71 Methyl butyrate (PC 71BM for short), [6,6 ]]-phenyl-C 61 Methyl butyrate (abbreviated as PC61 BM), 1',1",4',4" -tetrahydro-bis [1,4 ]]Methanonaphtho (methanonaphtho) [1,2:2',3',56, 60:2",3"][5，6]Fullerene-C 60 (abbreviated as ICBA) and the like.
As the non-fullerene electron acceptor, perylene derivatives, compounds having dicyanomethyleneindenyl groups, and the like can be used. N, N' -dimethyl-3, 4,9, 10-perylene dicarboximide (abbreviated as Me-PTCDI) and the like can be used.
[ examples of electron-donating materials ]
For example, phthalocyanine compounds, naphthacene derivatives, quinacridone derivatives, rubrene derivatives, and the like can be used for the electron donating material.
As the electron donating material, copper (II) phthalocyanine (abbreviated as CuPc), tin (II) phthalocyanine (abbreviated as SnPc), zinc phthalocyanine (abbreviated as ZnPc), tetraphenyl dibenzobisindenopyrene (abbreviated as DBP), rubrene, and the like can be used.
Structural example 2 of layer 114
For example, a single-layer structure or a stacked-layer structure may be used for the layer 114. Specifically, a bulk heterojunction structure may be used for the layer 114. In addition, a heterojunction type structure may be used for the layer 114.
[ structural example of Mixed Material ]
For example, a mixed material including an electron-accepting material and an electron-donating material may be used for the layer 114 (see fig. 5A). Note that a structure using a mixed material including an electron-accepting material and an electron-donating material as the layer 114 may be referred to as a bulk heterojunction type.
Specifically, C may be included 70 A mixed material of fullerene and DBP is used for the layer 114.
[ examples of heterojunction ]
Layers 114N and 114P may be used for layer 114. Layer 114N includes a region sandwiched between one electrode and layer 114P, and layer 114P includes a region sandwiched between layer 114N and the other electrode. For example, the layer 114N includes a region sandwiched between the electrode 102 and the layer 114P, and the layer 114P includes a region sandwiched between the layer 114N and the electrode 101S (see fig. 5B).
An N-type semiconductor may be used for layer 114N. For example, me-PTCDI may be used for layer 114N.
In addition, a P-type semiconductor may be used for the layer 114P. For example, rubrene may be used for layer 114P.
Note that the optical function device 170 having a structure in which the layer 114P is in contact with the layer 114N may be referred to as a PN junction photodiode.
< structural example 2 of cell 103S >
The unit 103S includes a layer 111 (2), and the layer 111 (2) includes a region sandwiched between the layer 114 and the layer 113 (refer to fig. 5C).
The structural example 2 of the unit 103S is different from the structural example 1 of the unit 103S in that the layer 111 (2) is included. Only the differences will be described in detail, and the above description is applied to the portions having the same structure.
Structural example of layer 111 (2)
For example, a light-emitting material or a host material may be used for the layer 111 (2). In addition, the layer 111 (2) may be referred to as a light emitting layer. Note that the layer 111 (2) is preferably arranged in a region where holes and electrons are recombined. This makes it possible to efficiently convert energy generated by carrier recombination into light and emit the light. In addition, the layer 111 (2) is preferably disposed away from the metal used for the electrode or the like. This can suppress quenching of the metal used for the electrode and the like.
Specifically, the structure described in embodiment 7 can be used for the layer 111 (2). In particular, as the layer 111 (2), a structure that emits light of a wavelength which is not easily absorbed by the layer 114 can be suitably employed. This allows light EL2 emitted from layer 111 (2) to be extracted efficiently.
Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification.
Embodiment 9
In this embodiment, a light-emitting device using the light-emitting device described in any one of embodiment modes 1 to 6 will be described.
In this embodiment, a light-emitting device manufactured using the light-emitting device described in any one of embodiment modes 1 to 6 will be described with reference to fig. 6. Note that fig. 6A is a top view showing the light emitting device, and fig. 6B is a sectional view cut along lines a-B and C-D in fig. 6A. The light-emitting device includes a driver circuit portion (source line driver circuit 601), a pixel portion 602, and a driver circuit portion (gate line driver circuit 603) which are indicated by dotted lines as means for controlling light emission of the light-emitting device. In addition, reference numeral 604 is a sealing substrate, reference numeral 605 is a sealant, and the inside surrounded by the sealant 605 is a space 607.
Note that the guide wiring 608 is a wiring for transmitting signals input to the source line driver circuit 601 and the gate line driver circuit 603, and receives a video signal, a clock signal, a start signal, a reset signal, and the like from an FPC (flexible printed circuit) 609 serving as an external input terminal. Note that although only an FPC is illustrated here, the FPC may be mounted with a Printed Wiring Board (PWB). The light-emitting device in this specification includes not only a light-emitting device main body but also a light-emitting device mounted with an FPC or a PWB.
Next, a cross-sectional structure is described with reference to fig. 6B. Although a driver circuit portion and a pixel portion are formed over the element substrate 610, one pixel of the source line driver circuit 601 and the pixel portion 602 which are driver circuit portions is shown here.
The element substrate 610 may be a substrate made of glass, quartz, an organic resin, a metal, an alloy, a semiconductor, or the like, or a plastic substrate made of FRP (Fiber Reinforced Plastics: fiber reinforced plastic), PVF (polyvinyl fluoride), polyester, acrylic, or the like.
The structure of the transistor for the pixel or the driving circuit is not particularly limited. For example, an inverted staggered transistor or a staggered transistor may be employed. In addition, either a top gate type transistor or a bottom gate type transistor may be used. The semiconductor material for the transistor is not particularly limited, and for example, silicon, germanium, silicon carbide, gallium nitride, or the like can be used. Or an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn metal oxide, may be used.
The crystallinity of the semiconductor material used for the transistor is not particularly limited, and an amorphous semiconductor or a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor in which a part thereof has a crystalline region) can be used. It is preferable to use a crystalline semiconductor because deterioration in characteristics of a transistor can be suppressed.
Here, the oxide semiconductor is preferably used for a semiconductor device such as a transistor provided in the above-described pixel or a driver circuit, a transistor used for a touch sensor or the like described later, or the like. Particularly, an oxide semiconductor having a wider band gap than silicon is preferably used. By using an oxide semiconductor having a wider band gap than silicon, off-state current (off-state current) of the transistor can be reduced.
The oxide semiconductor preferably contains at least indium (In) or zinc (Zn). The oxide semiconductor is more preferably an oxide semiconductor including an oxide expressed as an in—m—zn oxide (M is a metal such as Al, ti, ga, ge, Y, zr, sn, la, ce or Hf).
In particular, as the semiconductor layer, the following oxide semiconductor film is preferably used: the semiconductor device has a plurality of crystal portions each having a c-axis oriented in a direction perpendicular to a surface to be formed of the semiconductor layer or a top surface of the semiconductor layer, and no grain boundaries between adjacent crystal portions.
By using the above material for the semiconductor layer, a highly reliable transistor in which variation in electrical characteristics is suppressed can be realized.
In addition, since the off-state current of the transistor having the semiconductor layer is low, the charge stored in the capacitor through the transistor can be held for a long period of time. By using such a transistor for a pixel, the driving circuit can be stopped while maintaining the gradation of an image displayed in each display region. As a result, an electronic device with extremely low power consumption can be realized.
In order to stabilize the characteristics of the transistor, a base film is preferably provided. As the base film, an inorganic insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a silicon nitride oxide film can be used and manufactured in a single layer or stacked layers. The base film can be formed by a sputtering method, a CVD (Chemical Vapor Deposition: chemical vapor deposition) method (plasma CVD method, thermal CVD method, MOCVD (Metal Organic CVD: organometallic chemical vapor deposition) method, or the like), an ALD (Atomic Layer Deposition: atomic layer deposition) method, a coating method, a printing method, or the like. Note that the base film may be omitted if not required.
Note that the FET623 shows one of transistors formed in the source line driver circuit 601. The driving circuit may be formed using various CMOS circuits, PMOS circuits, or NMOS circuits. In addition, although the driver integrated type driver circuit in which the driver circuit is formed over the substrate is shown in this embodiment mode, this structure is not necessarily required, and the driver circuit may be formed outside rather than over the substrate.
The pixel portion 602 is formed of a plurality of pixels each including the switching FET611, the current control FET612, and the first electrode 613 electrically connected to the drain of the current control FET612, but the present invention is not limited thereto, and a pixel portion in which three or more FETs and capacitors are combined may be employed.
Note that an insulator 614 is formed to cover an end portion of the first electrode 613. Here, the insulator 614 may be formed using a positive type photosensitive acrylic resin film.
In addition, an upper end portion or a lower end portion of the insulator 614 is formed into a curved surface having a curvature to obtain good coverage of an EL layer or the like formed later. For example, in the case where a positive type photosensitive acrylic resin is used as a material of the insulator 614, it is preferable that only an upper end portion of the insulator 614 includes a curved surface having a radius of curvature (0.2 μm or more and 3 μm or less). As the insulator 614, a negative type photosensitive resin or a positive type photosensitive resin can be used.
An EL layer 616 and a second electrode 617 are formed over the first electrode 613. Here, as a material for the first electrode 613 which is used as an anode, a material having a large work function is preferably used. For example, a single-layer film such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing zinc oxide of 2wt% or more and 20wt% or less, a titanium nitride film, a chromium film, a tungsten film, a Zn film, a Pt film, or the like, a stacked film composed of a titanium nitride film and a film containing aluminum as a main component, a three-layer structure composed of a titanium nitride film, a film containing aluminum as a main component, a titanium nitride film, or the like may be used. Note that by adopting a stacked structure, the resistance value of the wiring can be low, good ohmic contact can be obtained, and it can be used as an anode.
The EL layer 616 is formed by various methods such as a vapor deposition method using a vapor deposition mask, an inkjet method, and a spin coating method. The EL layer 616 includes the structure shown in any of embodiment modes 1 to 6. As another material constituting the EL layer 616, a low molecular compound or a high molecular compound (including an oligomer and a dendrimer) can be used.
In addition, as a material for the second electrode 617 which is formed over the EL layer 616 and is used as a cathode, a material having a small work function (Al, mg, li, ca, an alloy thereof, a compound thereof (MgAg, mgIn, alLi, or the like) is preferably used. Note that when light generated in the EL layer 616 is transmitted through the second electrode 617, a stacked layer formed of a thin metal film and a transparent conductive film (ITO, indium oxide containing zinc oxide of 2wt% or more and 20wt% or less, indium tin oxide containing silicon, zinc oxide (ZnO), or the like) which are thinned is preferably used as the second electrode 617.
The light-emitting device 618 is formed of the first electrode 613, the EL layer 616, and the second electrode 617. The light-emitting device is the light-emitting device shown in any one of embodiment modes 1 to 6. The pixel portion is formed of a plurality of light emitting devices, and the light emitting device of this embodiment may include both the light emitting device described in any one of embodiment modes 1 to 6 and a light emitting device having another structure.
In addition, by attaching the sealing substrate 604 to the element substrate 610 with the sealant 605, the light-emitting device 618 is provided in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. Note that the space 607 is filled with a filler, and as the filler, an inert gas (nitrogen, argon, or the like) may be used, and a sealant may be used. By forming a recess in the sealing substrate and disposing a desiccant therein, deterioration due to moisture can be suppressed, so that it is preferable.
In addition, an epoxy resin or glass frit is preferably used as the sealant 605. In addition, these materials are preferably materials that are as impermeable as possible to moisture and oxygen. As a material for the sealing substrate 604, a plastic substrate composed of FRP (Fiber Reinforced Plastics; glass fiber reinforced plastic), PVF (polyvinyl fluoride), polyester, acrylic, or the like can be used in addition to a glass substrate or a quartz substrate.
Although not shown in fig. 6A and 6B, a protective film may be provided over the second electrode. The protective film may be formed of an organic resin film or an inorganic insulating film. The protective film may be formed so as to cover the exposed portion of the sealing agent 605. The protective film may be provided so as to cover the surfaces and side surfaces of the pair of substrates, and exposed side surfaces of the sealing layer, the insulating layer, and the like.
As the protective film, a material which is less likely to be permeable to impurities such as water can be used. Therefore, it is possible to efficiently suppress diffusion of impurities such as water from the outside to the inside.
As a material constituting the protective film, an oxide, nitride, fluoride, sulfide, ternary compound, metal, polymer, or the like can be used. For example, a material containing aluminum oxide, hafnium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide, titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide, cerium oxide, scandium oxide, erbium oxide, vanadium oxide, indium oxide, or a material containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, gallium nitride, a material containing titanium and aluminum nitride, titanium and aluminum oxide, aluminum and zinc oxide, manganese and zinc sulfide, cerium and strontium sulfide, erbium and aluminum oxide, yttrium and zirconium oxide, or the like can be used.
The protective film is preferably formed by a film forming method having excellent step coverage (step coverage). One such method is atomic layer deposition (ALD: atomic Layer Deposition). A material which can be formed by an ALD method is preferably used for the protective film. The ALD method can form a protective film which is dense, has reduced defects such as cracks and pinholes, and has a uniform thickness. In addition, damage to the processing member at the time of forming the protective film can be reduced.
For example, a uniform protective film with few defects can be formed on a surface having a complicated concave-convex shape or on the top surface, side surface, and back surface of a touch panel by an ALD method.
As described above, a light-emitting device manufactured using the light-emitting device described in any one of embodiment modes 1 to 6 can be obtained.
Since the light-emitting device in this embodiment mode uses the light-emitting device described in any one of embodiment modes 1 to 6, a light-emitting device having excellent characteristics can be obtained. Specifically, the light-emitting device shown in any one of embodiment modes 1 to 6 is used with good light-emitting efficiency, and thus a light-emitting device with low power consumption can be realized.
Fig. 7 shows an example of a light-emitting device in which full-color is achieved by forming a light-emitting device exhibiting white light emission and providing a colored layer (color filter) or the like. Fig. 7A shows a substrate 1001, a base insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral portion 1042, a pixel portion 1040, a driver circuit portion 1041, first electrodes 1024W, 1024R, 1024G, 1024B of a light-emitting device, a partition wall 1025, an EL layer 1028, a second electrode 1029 of the light-emitting device, a sealing substrate 1031, a sealing agent 1032, and the like.
In fig. 7A, a coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) is provided on a transparent base material 1033. In addition, a black matrix 1035 may be provided. The transparent base 1033 provided with the coloring layer and the black matrix is aligned and fixed to the substrate 1001. In addition, the coloring layer and the black matrix 1035 are covered with the protective layer 1036. Fig. 7A shows a light-emitting layer through which light is transmitted to the outside without passing through the colored layer, and a light-emitting layer through which light is transmitted to the outside with passing through the colored layers, and light that does not pass through the colored layers becomes white light and light that passes through the colored layers becomes red light, green light, and blue light, so that an image can be displayed in pixels of four colors.
Fig. 7B shows an example in which coloring layers (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) are formed between the gate insulating film 1003 and the first interlayer insulating film 1020. As described above, a coloring layer may be provided between the substrate 1001 and the sealing substrate 1031.
In addition, although a light-emitting device having a structure in which light is extracted from the substrate 1001 side where an FET is formed (bottom emission type) has been described above, a light-emitting device having a structure in which light is extracted from the sealing substrate 1031 side (top emission type) may be used. Fig. 8 shows a cross-sectional view of a top emission type light emitting device. In this case, a substrate which does not transmit light can be used for the substrate 1001. The process until the connection electrode for connecting the FET to the anode of the light emitting device is manufactured is performed in the same manner as in the bottom emission type light emitting device. Then, a third interlayer insulating film 1037 is formed so as to cover the electrode 1022. The insulating film may have a planarizing function. The third interlayer insulating film 1037 may be formed using the same material as the second interlayer insulating film or other known materials.
Although the first electrodes 1024W, 1024R, 1024G, 1024B of the light-emitting device are all anodes here, they may be cathodes. In addition, in the case of using a top emission type light emitting device as shown in fig. 8, the first electrode is preferably a reflective electrode. The structure of the EL layer 1028 adopts the structure of the cell 103 shown in any one of embodiment modes 1 to 6, and adopts an element structure capable of obtaining white light emission.
In the case of employing the top emission structure shown in fig. 8, sealing can be performed using a sealing substrate 1031 provided with coloring layers (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B). The sealing substrate 1031 may also be provided with a black matrix 1035 located between pixels. The coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) or the black matrix may also be covered with a protective layer 1036. As the sealing substrate 1031, a substrate having light transmittance is used. Although the example of full-color display in four colors of red, green, blue, and white is shown here, the present invention is not limited to this, and full-color display in four colors of red, yellow, green, and blue or three colors of red, green, and blue may be used.
In the top emission type light emitting device, a microcavity structure may be preferably applied. A reflective electrode is used as a first electrode and a transflective electrode is used as a second electrode, whereby a light emitting device having a microcavity structure can be obtained. The reflective electrode and the transflective electrode have at least an EL layer therebetween and at least a light-emitting layer serving as a light-emitting region.
Note that the reflective electrode is a reflective electrode having a visible light reflectance of 40% to 100%, preferably 70% to 100%, and a resistivity of 1×10 -2 Films of Ω cm or less. In addition, the transflective electrode is 20% to 80% in visible light reflectance, preferably 40% to 70%, and has a resistivity of 1×10 -2 Films of Ω cm or less.
Light emitted from the light-emitting layer included in the EL layer is reflected by the reflective electrode and the semi-transmissive and semi-reflective electrode, and resonates.
In this light-emitting device, the optical path between the reflective electrode and the transflective electrode can be changed by changing the thickness of the transparent conductive film, the above-described composite material, the carrier transporting material, or the like. This enhances the light of the resonant wavelength between the reflective electrode and the transflective electrode, and attenuates the light of the non-resonant wavelength.
Since the light reflected by the reflective electrode (first reflected light) greatly interferes with the light (first incident light) directly entering the transflective electrode from the light-emitting layer, the optical path length between the reflective electrode and the light-emitting layer is preferably adjusted to (2 n-1) λ/4 (note that n is a natural number of 1 or more, and λ is the wavelength of the light to be enhanced). By adjusting the optical path, the first reflected light can be made to coincide with the phase of the first incident light, whereby the light emitted from the light emitting layer can be further enhanced.
In the above structure, the EL layer may include a plurality of light-emitting layers or may include only one light-emitting layer. For example, the following structure may be adopted: in combination with the structure of the above-described tandem type light emitting device, a plurality of EL layers are provided in one light emitting device with a charge generation layer interposed therebetween, and one or more light emitting layers are formed in each EL layer.
By adopting the microcavity structure, the light emission intensity in the front direction of the specified wavelength can be enhanced, whereby low power consumption can be achieved. Note that in the case of a light-emitting device that displays an image for sub-pixels using four colors of red, yellow, green, and blue, since a luminance improvement effect due to yellow light emission can be obtained, and a microcavity structure suitable for the wavelength of each color can be employed in all the sub-pixels, a light-emitting device having good characteristics can be realized.
Since the light-emitting device in this embodiment mode uses the light-emitting device described in any one of embodiment modes 1 to 6, a light-emitting device having excellent characteristics can be obtained. Specifically, the light-emitting device shown in any one of embodiment modes 1 to 6 is used with good light-emitting efficiency, and thus a light-emitting device with low power consumption can be realized.
Although the active matrix type light emitting device is described here, the passive matrix type light emitting device is described below. Fig. 9 shows a passive matrix type light emitting device manufactured by using the present invention. Note that fig. 9A is a perspective view showing a light emitting device, and fig. 9B is a sectional view obtained by cutting along a line X-Y of fig. 9A. In fig. 9, an EL layer 955 is provided between an electrode 952 and an electrode 956 over a substrate 951. The end of the electrode 952 is covered with an insulating layer 953. An isolation layer 954 is provided on the insulating layer 953. The sidewalls of the isolation layer 954 have an inclination such that the closer to the substrate surface, the narrower the separation between the two sidewalls. In other words, the cross section of the isolation layer 954 in the short side direction is trapezoidal, and the bottom side (side facing the same direction as the surface direction of the insulating layer 953 and contacting the insulating layer 953) is shorter than the upper side (side facing the same direction as the surface direction of the insulating layer 953 and not contacting the insulating layer 953). Thus, by providing the isolation layer 954, defects of the light emitting device due to static electricity or the like can be prevented. In addition, in the passive matrix light-emitting device, a light-emitting device with good reliability or a light-emitting device with low power consumption can be obtained by using the light-emitting device according to any one of embodiments 1 to 6.
The light emitting device described above can control each of the plurality of minute light emitting devices arranged in a matrix, and therefore can be suitably used as a display device for displaying an image.
In addition, this embodiment mode can be freely combined with other embodiment modes.
Embodiment 10
In this embodiment, an example in which a light-emitting device described in any one of embodiments 1 to 6 is used for a lighting device will be described with reference to fig. 10. Fig. 10B is a top view of the lighting device, and fig. 10A is a cross-sectional view along line e-f of fig. 10B.
In the lighting device of the present embodiment, the first electrode 401 is formed over the light-transmitting substrate 400 serving as a support. The first electrode 401 corresponds to the electrode 101 in any one of embodiment modes 1 to 6. When light is extracted from the first electrode 401 side, the first electrode 401 is formed using a material having light transmittance.
In addition, a pad 412 for supplying a voltage to the second electrode 404 is formed on the substrate 400.
An EL layer 403 is formed over the first electrode 401. The EL layer 403 corresponds to a structure in which the layer 104, the cell 103, and the layer 105 in any one of embodiments 1 to 6 are combined, a structure in which the layer 104, the cell 103, the intermediate layer 106, the cell 103 (2), and the layer 105 in any one of embodiments 1 to 6 are combined, or the like. Note that, as the structures thereof, the respective descriptions are referred to.
The second electrode 404 is formed so as to cover the EL layer 403. The second electrode 404 corresponds to the electrode 102 in any one of embodiment modes 1 to 6. When light is extracted from the first electrode 401 side, the second electrode 404 is formed using a material with high reflectance. By connecting the second electrode 404 with the pad 412, a voltage is supplied to the second electrode 404.
As described above, the lighting device according to the present embodiment includes the light-emitting device including the first electrode 401, the EL layer 403, and the second electrode 404. Since the light emitting device is a light emitting device having high light emitting efficiency, the lighting device of the present embodiment can be a low-power-consumption lighting device.
The substrate 400 formed with the light-emitting device having the above structure and the sealing substrate 407 are fixed with the sealants 405 and 406 to be sealed, thereby manufacturing a lighting device. In addition, only one of the sealants 405 and 406 may be used. In addition, the inside sealing agent 406 (not shown in fig. 10B) may be mixed with the desiccant, whereby moisture may be absorbed to improve reliability.
In addition, by providing the pad 412 and a part of the first electrode 401 so as to extend to the outside of the sealants 405, 406, it can be used as an external input terminal. Further, an IC chip 420 or the like to which a converter or the like is mounted may be provided on the external input terminal.
The lighting device described in this embodiment can realize a lighting device with low power consumption by using the light-emitting device described in any one of embodiments 1 to 6 for the EL element.
Embodiment 11
In this embodiment, an example of an electronic device including the light-emitting device according to any one of embodiments 1 to 6 in part thereof will be described. The light-emitting device described in any one of embodiment modes 1 to 6 is a light-emitting device having excellent light-emitting efficiency and low power consumption. As a result, the electronic device according to the present embodiment can realize an electronic device including a light-emitting portion with low power consumption.
Examples of the electronic device using the light emitting device include a television set (also referred to as a television or a television receiver), a display for a computer or the like, a digital camera, a digital video camera, a digital photo frame, a mobile phone (also referred to as a mobile phone or a mobile phone device), a portable game machine, a portable information terminal, a sound reproducing device, a large-sized game machine such as a pachinko machine, and the like. Specific examples of these electronic devices are shown below.
Fig. 11A shows an example of a television apparatus. In the television device, a display portion 7103 is incorporated in a housing 7101. Here, a structure in which the housing 7101 is supported by a bracket 7105 is shown. The display portion 7103 can be configured by displaying an image on the display portion 7103 and arranging the light emitting devices described in any one of embodiments 1 to 6 in a matrix.
The television device can be operated by an operation switch included in the housing 7101 or a remote control operation device 7110 provided separately. By using the operation key 7109 included in the remote control unit 7110, the channel or the volume can be controlled, and thus the image displayed on the display portion 7103 can be controlled. The remote controller 7110 may be provided with a display portion 7107 for displaying information outputted from the remote controller 7110.
In addition, the television apparatus adopts a configuration including a receiver, a modem, or the like. A general television broadcast may be received by a receiver. Further, the modem is connected to a wired or wireless communication network, and can perform one-way (from a sender to a receiver) or two-way (between a sender and a receiver, between receivers, or the like) information communication.
Fig. 11B shows a computer including a main body 7201, a housing 7202, a display portion 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, and the like. The computer is manufactured by arranging light emitting devices shown in any one of embodiment modes 1 to 6 in a matrix and using the light emitting devices in the display portion 7203. The computer in fig. 11B may be as shown in fig. 11C. The computer shown in fig. 11C is provided with a second display portion 7210 instead of the keyboard 7204 and the pointing device 7206. The second display portion 7210 is a touch panel, and input can be performed by manipulating the input display displayed on the second display portion 7210 with a finger or a dedicated pen. The second display unit 7210 can display not only the input display but also other images. The display portion 7203 may be a touch panel. Because the two panels are connected by the hinge portion, it is possible to prevent problems such as injury, damage, etc. of the panels from occurring at the time of storage or transportation.
Fig. 11D shows an example of a portable terminal. The portable terminal includes a display portion 7402, an operation button 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like, which are assembled in a housing 7401. The portable terminal includes a display portion 7402 formed by arranging light emitting devices shown in any one of embodiments 1 to 6 in a matrix.
The mobile terminal shown in fig. 11D may have a structure in which a finger or the like touches the display portion 7402 to input information. In this case, the display portion 7402 can be touched with a finger or the like to perform an operation such as making a call or writing an email.
The display portion 7402 mainly has three screen modes. The first is a display mode mainly for displaying an image, the second is an input mode mainly for inputting information such as characters, and the third is a display input mode of two modes of a mixed display mode and an input mode.
For example, in the case of making a call or composing an email, a text input mode in which the display portion 7402 is mainly used for inputting text may be employed to input text displayed on a screen. In this case, a keyboard or number buttons are preferably displayed in most part of the screen of the display portion 7402.
Further, by providing a detection device including a sensor for detecting inclination such as a gyro sensor or an acceleration sensor in the mobile terminal, the direction (vertical or horizontal) of the mobile terminal can be determined, and the screen display of the display portion 7402 can be automatically switched.
The screen mode is switched by touching the display portion 7402 or operating an operation button 7403 of the housing 7401. Alternatively, the screen mode may be switched according to the type of image displayed on the display portion 7402. For example, when an image signal displayed on the display section is data of a moving image, the screen mode is switched to the display mode, and when the image signal is text data, the screen mode is switched to the input mode.
In addition, when it is known that no touch operation is input to the display portion 7402 for a certain period of time by detecting a signal detected by the light sensor of the display portion 7402 in the input mode, control may be performed to switch the screen mode from the input mode to the display mode.
The display portion 7402 can also be used as an image sensor. For example, by touching the display portion 7402 with a palm or a finger to capture a palm print, a fingerprint, or the like, personal identification can be performed. Further, by using a backlight that emits near-infrared light or a light source for sensing that emits near-infrared light in the display portion, a finger vein, a palm vein, or the like can be imaged.
Fig. 12A is a schematic diagram showing an example of the sweeping robot.
The sweeping robot 5100 includes a display 5101 on a top surface and a plurality of cameras 5102, brushes 5103, and operation buttons 5104 on side surfaces. Although not shown, a tire, a suction port, and the like are provided on the bottom surface of the sweeping robot 5100. The floor sweeping robot 5100 further includes various sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezoelectric sensor, a photosensor, and a gyro sensor. In addition, the sweeping robot 5100 includes a wireless communication unit.
The robot 5100 can automatically travel to detect the refuse 5120 and suck the refuse from the suction port on the bottom surface.
Further, the robot 5100 analyzes an image captured by the camera 5102 to determine whether or not an obstacle such as a wall, furniture, or a step is present. In addition, in the case where an object, such as a wiring, which may be wound around the brush 5103 is detected by image analysis, the rotation of the brush 5103 may be stopped.
The remaining amount of battery or the amount of attracted garbage, etc. may be displayed on the display 5101. The travel path of the sweeping robot 5100 may be displayed on the display 5101. Further, the display 5101 may be a touch panel, and the operation buttons 5104 may be displayed on the display 5101.
The sweeping robot 5100 may communicate with a portable electronic device 5140 such as a smart phone. The image captured by the camera 5102 may be displayed on the portable electronic device 5140. Therefore, the owner of the sweeping robot 5100 can also know the condition of the room when he/she is out. In addition, the display content of the display 5101 can be confirmed using a portable electronic device 5140 such as a smart phone.
The light-emitting device according to one embodiment of the present invention can be used for the display 5101.
The robot 2100 shown in fig. 12B includes an arithmetic device 2110, an illuminance sensor 2101, a microphone 2102, an upper camera 2103, a speaker 2104, a display 2105, a lower camera 2106, an obstacle sensor 2107, and a moving mechanism 2108.
The microphone 2102 has a function of detecting a user's voice, surrounding voice, and the like. In addition, the speaker 2104 has a function of emitting sound. The robot 2100 may communicate with a user using a microphone 2102 and a speaker 2104.
The display 2105 has a function of displaying various information. The robot 2100 may display information desired by the user on the display 2105. The display 2105 may also be mounted with a touch panel. The display 2105 may be a detachable information terminal, and by providing the information terminal at a predetermined position of the robot 2100, charging and data transmission/reception can be performed.
The upper camera 2103 and the lower camera 2106 have a function of capturing images of the surrounding environment of the robot 2100. The obstacle sensor 2107 may detect the presence or absence of an obstacle ahead when the robot 2100 moves using the moving mechanism 2108. The robot 2100 can safely move by recognizing the surrounding environment using the upper camera 2103, the lower camera 2106, and the obstacle sensor 2107. The light emitting device according to one embodiment of the present invention can be used for the display 2105.
Fig. 12C is a diagram showing an example of a goggle type display. The goggle type display includes, for example, a housing 5000, a display portion 5001, a speaker 5003, an LED lamp 5004, an operation key (including a power switch or an operation switch), a connection terminal 5006, a sensor 5007 (which has a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, an electric field, current, voltage, electric power, radiation, flow, humidity, inclination, vibration, smell, or infrared rays), a microphone 5008, a display portion 5002, a support portion 5012, an earphone 5013, and the like.
The light-emitting device according to one embodiment of the present invention can be used for the display portion 5001 and the display portion 5002.
Fig. 13 shows an example in which the light-emitting device according to any one of embodiment modes 1 to 6 is used for a desk lamp as a lighting device. The desk lamp shown in fig. 13 includes a housing 2001 and a light source 2002, and the lighting device described in embodiment 10 is used as the light source 2002.
Fig. 14 shows an example in which the light-emitting device described in any one of embodiment modes 1 to 6 is used for an indoor lighting device 3001. Since the light-emitting device shown in any one of embodiment modes 1 to 6 is a light-emitting device having high light-emitting efficiency, a lighting device with low power consumption can be provided. In addition, the light-emitting device according to any one of embodiment modes 1 to 6 can be used for a large-area lighting device because the light-emitting device can be made large in area. Further, since the light-emitting device described in any one of embodiment modes 1 to 6 has a small thickness, the light-emitting device can be used as a lighting device which realizes a thin shape.
The light emitting device shown in any one of embodiment modes 1 to 6 can also be mounted on a windshield or a dashboard of an automobile. Fig. 15 shows one embodiment in which the light-emitting device according to any one of embodiment 1 to embodiment 6 is used for a windshield or a dashboard of an automobile. The display regions 5200 to 5203 are display regions provided using the light emitting device described in any one of embodiment modes 1 to 6.
The display region 5200 and the display region 5201 are display devices provided on a windshield of an automobile, on which the light emitting device according to any one of embodiments 1 to 6 is mounted. By manufacturing the first electrode and the second electrode of the light-emitting device shown in any one of embodiment modes 1 to 6 using an electrode having light transmittance, a so-called see-through display device in which a view of the opposite surface can be seen can be obtained. If the see-through display is used, the visibility is not impaired even if the display is provided on a windshield of an automobile. In addition, in the case of providing a transistor or the like for driving, a transistor having light transmittance such as an organic transistor using an organic semiconductor material or a transistor using an oxide semiconductor or the like is preferably used.
The display region 5202 is a display device provided in a pillar portion to which the light emitting device according to any one of embodiment modes 1 to 6 is mounted. By displaying an image from an imaging unit provided on the vehicle cabin on the display area 5202, the view blocked by the pillar can be supplemented. In addition, similarly, the display area 5203 provided on the instrument panel portion can supplement the dead angle of the view blocked by the vehicle cabin by displaying an image from the imaging unit provided on the outside of the vehicle, thereby improving safety. By displaying the image to supplement the invisible portion, security is more naturally and simply confirmed.
The display area 5203 can provide various information by displaying navigation information, speed or rotation speed, distance travelled, fuel remaining, gear state, setting of air conditioner, and the like. The user can change the display contents or arrangement appropriately. In addition, such information may also be displayed on the display area 5200 to the display area 5202. In addition, the display regions 5200 to 5203 may also be used as illumination devices.
Further, fig. 16A to 16C show a portable information terminal 9310 capable of folding. Fig. 16A shows the portable information terminal 9310 in an expanded state. Fig. 16B shows the portable information terminal 9310 in a state halfway from one of the unfolded state and the folded state to the other. Fig. 16C shows the portable information terminal 9310 in a folded state. The portable information terminal 9310 is excellent in portability in a folded state and has a large display area seamlessly spliced in an unfolded state, so that it has a strong display list.
The display panel 9311 is supported by three frames 9315 connected by a hinge portion 9313. Note that the display panel 9311 may be a touch panel (input/output device) to which a touch sensor (input device) is attached. In addition, by bending the display panel 9311 at the hinge portion 9313 between the two housings 9315, the portable information terminal 9310 can be reversibly changed from an unfolded state to a folded state. The light emitting device according to one embodiment of the present invention can be used for the display panel 9311.
The structure shown in this embodiment mode can be used in combination with the structures shown in embodiment modes 1 to 6 as appropriate.
As described above, the application range of the light-emitting device including the light-emitting device described in any one of embodiment modes 1 to 6 is extremely wide, and the light-emitting device can be used for electronic equipment in various fields. By using the light-emitting device described in any one of embodiment modes 1 to 6, an electronic device with low power consumption can be obtained.
Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification.
Example 1
In this embodiment, a light emitting device 222 (22) according to an embodiment of the present invention is described with reference to fig. 17 to 45. Note that, for convenience, the subscript characters and the superscript characters are described in the drawings and tables of the present embodiment in standard sizes. For example, both the subscript character in the abbreviation and the superscript character in the unit are described in the table in standard sizes. The description in the above table may be replaced with the description in the specification.
Fig. 17A to 17C are diagrams illustrating the structure of the light emitting device 150.
FIG. 18 is a graph illustrating the absorption spectrum, ir (5 tBuppy), of TTPA 3 A graph of the emission spectrum of TTPA and the emission spectrum of TTPA.
FIG. 19 is a graph illustrating the absorption spectrum, ir (4 tBuppy), of TTPA 3 A graph of the emission spectrum of TTPA and the emission spectrum of TTPA.
FIG. 20 is a graph showing the absorption spectrum, ir (5 tBuppy), of 2Ph-mmtBuDPhA2Anth 3 Is 2Ph-mmtBuDGraph of emission spectrum of PhA2 Anth.
FIG. 21 is a graph showing the absorption spectrum, ir (4 tBuppy), of 2Ph-mmtBuDPhA2Anth 3 And the emission spectrum of 2Ph-mmtBuDPhA2 Anth.
Fig. 22 is a diagram illustrating current density-luminance characteristics of the light emitting device 222 (22).
Fig. 23 is a diagram illustrating luminance-current efficiency characteristics of the light emitting device 222 (22).
Fig. 24 is a diagram illustrating voltage-luminance characteristics of the light emitting device 222 (22).
Fig. 25 is a diagram illustrating voltage-current characteristics of the light emitting device 222 (22).
Fig. 26 is a diagram illustrating luminance-external quantum efficiency characteristics of the light emitting device 222 (22). Note that, assuming that the light distribution characteristic of the light emitting device is lambertian, the external quantum efficiency is calculated from the luminance.
FIG. 27 is a view illustrating the light-emitting device 222 (22) being made to be 1000cd/m 2 Is a graph of an emission spectrum when the luminance of the light is emitted.
FIG. 28 is a graph illustrating the flow rate of 50mA/cm 2 A graph of normalized luminance versus time characteristics when the light emitting device 222 (22) emits light.
Fig. 29 is a diagram illustrating voltage-current characteristics of the reference device.
FIG. 30 is a graph illustrating the flow rate of 2.5mA/cm 2 The current density of (2) is such that the reference device emits light.
FIG. 31 is a view equivalent to 1300cd/m 2 A graph of a change in light emission intensity of the pulse-driven light emitting device.
< light-emitting device 222 (22) >)
The light emitting device 222 (22) manufactured as described in this embodiment has the same structure as the light emitting device 150 (see fig. 17A).
The light-emitting device 150 includes an electrode 101, an electrode 102, and a layer 111 (see fig. 17A). Electrode 102 includes an area overlapping electrode 101 with layer 111 between electrode 101 and electrode 102.
The layer 111 comprises a luminescent material FM, an energy donor material ED and a host material.
The luminescent material FM has a function of emitting fluorescence, and has an end located at the longest wavelength of the absorption spectrum Abs at the wavelength λabs (nm) (see fig. 17C).
Use of an organometallic complex as energy donor material ED, the organometallic complex comprising a ligand comprising a substituent R 1 Substituent R 1 Is any of alkyl, cycloalkyl and trialkylsilyl groups. Note that the number of carbon atoms of the alkyl group is 3 or more and 12 or less, the number of ring-forming carbon atoms of the cycloalkyl group is 3 or more and 10 or less, and the number of carbon atoms of the trialkylsilyl group is 3 or more and 12 or less.
In addition, the organometallic complex has a function of emitting phosphorescence at room temperature, the phosphorescence having an end portion located at the shortest wavelength of the spectrum at a wavelength λp (nm), the wavelength λp being located at a short wavelength compared to the wavelength λabs.
The organometallic complex has a first HOMO level HOMO1 and a first LUMO level LUMO1 (see fig. 17B).
The host material has a function of emitting delayed fluorescence at room temperature, and has a second HOMO level HOMO2 and a second LUMO level LUMO2.
The first HOMO level HOMO1, the first LUMO level LUMO1, the second HOMO level HOMO2, and the second LUMO level LUMO2 satisfy the following expression (1).
[ calculation formula 7]
(LUMO2-HOMO2)＜(LUMO1-HOMO1)···(1)
Structure of light-emitting device 222 (22)
Table 1 shows the structure of the light emitting device 222 (22). In addition, the structural formula of the material used for the light emitting device described in this embodiment, and the HOMO level and LUMO level are shown below.
The 2 Ph-mmtbudppa 2Anth of the light-emitting material FM for the light-emitting device 222 (22) has an end located at the longest wavelength of the absorption spectrum at wavelength 519nm (refer to fig. 20). Note that the absorption spectrum of the luminescent material FM in a toluene solution was measured at room temperature using an ultraviolet-visible spectrophotometer (model V550 manufactured by japan spectroscopy).
Organometallic complexes for light emitting device 222 (22)Ir(5tBuppy) 3 Has the function of emitting phosphorescence. The phosphorescence has an end portion at the shortest wavelength of the spectrum at wavelength 484nm, which end portion is at a short wavelength compared to wavelength 519 nm. In addition, ir (5 tBuppy) 3 Has a first HOMO level HOMO1 at-5.32 eV and a first LUMO level LUMO1 at-2.25 eV. Note that measurement of phosphorescence spectrum of the organometallic complex in methylene chloride solution was performed using a fluorescence spectrophotometer (model FP-8600 manufactured by japan spectroscopy corporation) at room temperature. The HOMO and LUMO levels of the organometallic complex were calculated from oxidation and reduction potentials obtained by Cyclic Voltammetry (CV) measurement using an electrochemical analyzer (model: ALS 600A or 600C, manufactured by BAS Co., ltd.).
The material of the host material for the light emitting device 222 (22) has a function of emitting delayed fluorescence. Specifically, mPCzPTzn-02 emits delayed fluorescence. In addition, the material has a second HOMO level HOMO2 at-5.69 eV and a second LUMO level LUMO2 at-3.00 eV (see Table 2). Note that the HOMO level and LUMO level of the host material were calculated from oxidation potential and reduction potential obtained by Cyclic Voltammetry (CV) measurement using an electrochemical analyzer (model: ALS 600A or 600C, manufactured by BAS corporation).
Note that the value of (LUMO 2-HOMO 2) is 2.69eV, which is smaller than the value of (LUMO 1-HOMO 1), i.e., 3.07eV.
TABLE 1
[ chemical formula 18]
[ chemical formula 19]
[ chemical formula 20]
TABLE 2
Method for manufacturing light-emitting device 222 (22)
The light emitting device 222 (22) described in this embodiment is manufactured by a method including the following steps.
[ first step ]
In a first step, the electrode 101 is formed. Specifically, the electrode 101 is formed by a sputtering method using indium oxide-tin oxide (abbreviated as ITSO) containing silicon or silicon oxide as a target.
Note that the electrode 101 contains ITSO with a thickness of 70nm and an area of 4mm 2 (2mm×2mm)。
Next, the substrate on which the electrode 101 was formed was washed with water, baked at 200 ℃ for 1 hour, and then subjected to UV ozone treatment for 370 seconds. Then, the substrate was put into the inside thereof and depressurized to 10 -4 In a vacuum vapor deposition apparatus of the order Pa, vacuum baking is performed at 170℃for 30 minutes in a heating chamber in the vacuum vapor deposition apparatus. Then, the substrate was cooled for about 30 minutes.
[ second step ]
In a second step, layer 104 is formed on electrode 101. Specifically, the material is co-evaporated by a resistance heating method.
Note that layer 104 includes 4,4',4"- (benzene-1, 3, 5-triyl) tris (dibenzothiophene) (abbreviated as DBT 3P-II) and molybdenum (VI) oxide (abbreviated as MoO 3 ) The weight ratio of the DBT3P-II is as follows: moO (MoO) 3 =1: 0.5, the thickness of which is 40nm.
Third step
In a third step, layer 112 is formed over layer 104. Specifically, the material is deposited by a resistance heating method.
Note that layer 112 contains 9- [3- (9-phenyl-9H-fluoren-9-yl) phenyl ] -9H-carbazole (abbreviated as mCzFLP) with a thickness of 20nm.
[ fourth step ]
In a fourth step, layer 111 is formed on layer 112. Specifically, the material is co-evaporated by a resistance heating method.
Note that layer 111 comprises 9- [3- (4, 6-diphenyl-1, 3, 5-triazin-2-yl) phenyl ]]-9 '-phenyl-2, 3' -bi-9H-carbazole (abbreviated as: mPCzPTzn-02), tris [2- [5- (tert-butyl) -2-pyridinyl-kappa N ]]Phenyl-kappa C]Iridium (abbreviated as Ir (5 tBuuppy) 3 ) And N, N '-bis (3, 5-di-tert-butylphenyl) -N, N' -bis [3, 5-bis (3, 5-di-tert-butylphenyl) phenyl]-2-phenylanthracene-9, 10-diamine (abbreviated as: 2Ph-mmtBuDPhA2 Anth) in a weight ratio of mPCzPTzn-02: ir (5 tBuppy) 3 :2 Ph-mmtbudppa2anth=1: 0.1:0.05, with a thickness of 40nm. Note that mPCCzPTzn-02 is a substance exhibiting heat-activated delayed fluorescence.
TABLE 3
[ fifth step ]
In a fifth step, layer 113A is formed over layer 111. Specifically, the material is deposited by a resistance heating method.
Note that layer 113A contains 3, 5-bis [3- (9H-carbazol-9-yl) phenyl ] pyridine (abbreviated as 35 DCzPPy) with a thickness of 20nm.
Sixth step
In the sixth step, layer 113B is formed on layer 113A. Specifically, the material is deposited by a resistance heating method.
Note that layer 113B contains 1,3, 5-tris [3- (3-pyridyl) phenyl ] benzene (abbreviated as TmPyPB) with a thickness of 10nm.
Seventh step
In a seventh step, layer 105 is formed over layer 113B. Specifically, the material is deposited by a resistance heating method.
Note that layer 105 contains lithium fluoride (abbreviated as LiF) with a thickness of 1nm.
[ eighth step ]
In an eighth step, the electrode 102 is formed on the layer 105. Specifically, the material is deposited by a resistance heating method.
Note that the electrode 102 contains aluminum (abbreviated as Al) with a thickness of 200nm.
Operating characteristics of light-emitting device 222 (22) >
The light emitting device 222 (22) emits green light EL1 when supplied with power (refer to fig. 17A). The operation characteristics of the light emitting device 222 (22) are measured (refer to fig. 22 to 27). Note that the luminance, CIE chromaticity, and emission spectrum were measured at room temperature using a spectroradiometer (SR-UL 1R manufactured by trapkang).
Table 4 shows that the light-emitting device manufactured was made to be 1000cd/m 2 The main initial characteristics of the left and right luminance light emission. In addition, table 4 shows LT90, which means that the temperature of the alloy at a constant current density (50 mA/cm 2 ) The elapsed time from the reduction of the luminance to 90% of the initial luminance when the light-emitting device emits light was reduced. In addition, table 4 also shows characteristics of other light emitting devices, and their structures will be described later.
TABLE 4
It can be seen that the light emitting device 222 (22) exhibits good characteristics. For example, the light emitting device 222 (22) emits light from an emission spectrum of the light emitting material FM having a peak wavelength at about 540nm (refer to fig. 27). In addition, no luminescence from the energy donor material ED was observed. Alternatively, energy is transferred from the energy donor material ED to the luminescent material FM. In addition, undesired energy transfer from the energy donor material ED to the luminescent material FM can be suppressed. In addition, energy transfer from the energy donor material ED to the light emitting material FM based on the tex mechanism can be suppressed.
In addition, the light emitting device 222 (22) may realize 1000cd/m at a voltage lower than that of the comparing device 022 (22) and the comparing device 021 (22) 2 Left and right brightness (see table 4). In addition, higher external appearance is exhibited as compared to the comparison device 022 (22)Quantum efficiency. In addition, higher external quantum efficiency is exhibited compared to the comparison device 021 (22).
In addition, at 50mA/cm 2 When the light emitting device emits light, the time required for the luminance of the light emitting device 222 (22) to decrease to 90% of the initial luminance is longer than that of the comparison device 022 (22).
Reference example 1
The comparative device 022 (22) manufactured as described in this reference example is different from the light-emitting device 222 (22) in that 3,3' -9H-carbazol-9-yl-biphenyl (abbreviated as "mCBP") is used as a host material instead of mpczptzn-02. In addition, the manufactured comparison device 021 (22) described in this reference example is different from the light emitting device 222 (22) in that: mCBP was used as a host material instead of mpczptzn-02; and N, N, N ', N' -tetrakis (4-methylphenyl) -9, 10-anthracenediamine (abbreviated as TTPA) was used as the light-emitting material FM in place of 2Ph-mmtBuDPhA2Anth.
Structure of comparison device 022 (22)
Table 5 shows the structure of the comparison device 022 (22) manufactured as described in this reference example. Note that the comparison device 022 (22) is different from the light-emitting device 222 (22) in that mCBP is used as a host material.
mCBP, which is a host material for the light emitting device 022 (22), does not emit delayed fluorescence. In addition, the material has a second HOMO level HOMO2 at-5.93 eV and a second LUMO level LUMO2 at-2.22 eV (see Table 2). Note that the HOMO level and LUMO level of the host material were calculated from oxidation potential and reduction potential obtained by Cyclic Voltammetry (CV) measurement using an electrochemical analyzer (model: ALS 600A or 600C, manufactured by BAS corporation).
Note that the value of (LUMO 2-HOMO 2) is 3.71eV, which is greater than the value of (LUMO 1-HOMO 1), i.e., 3.07eV.
TABLE 5
[ chemical formula 21]
Method for manufacturing comparative device 022 (22)
The light emitting device 022 (22) described in this embodiment is manufactured by a method including the following steps.
Note that the manufacturing method of the light emitting device 022 (22) is different from the manufacturing method of the light emitting device 222 (22) in that: in the step of forming the layer 111, mCBP is used instead of mpczptzn-02 as a host material. The differences will be described in detail herein, and the above description is applied to portions using the same method.
[ fourth step ]
In a fourth step, layer 111 is formed on layer 112. Specifically, the material is co-evaporated by a resistance heating method.
Note that layer 111 comprises mCBP, ir (5 tBuppy) 3 And 2Ph-mmtBuDPhA2Anth in the weight ratio mCBP: ir (5 tBuppy) 3 :2 Ph-mmtbudppa2anth=1: 0.1:0.05, and the thickness thereof was 40nm (see Table 3).
Structure of comparison device 021 (22)
The manufactured comparison device 021 (22) described in this reference example is different from the light emitting device 222 (22) in that: mCBP was used as a host material; and as luminescent material FM TTPA was used instead of 2Ph-mmtBuDPhA2Anth.
mCBP, which is a host material for the light emitting device 022 (22), does not emit delayed fluorescence. In addition, the material has a second HOMO level HOMO2 at-5.93 eV and a second LUMO level LUMO2 at-2.22 eV (see Table 2).
Note that the value of (LUMO 2-HOMO 2) is 3.71eV, which is greater than the value of (LUMO 1-HOMO 1), i.e., 3.07eV.
In addition, the TTPA of the luminescent material FM for the luminescent device 021 (22) comprises a second substituent R 2 . A second substituent R 2 Is methyl.
Method for manufacturing comparison device 021 (22)
The light emitting device 021 (22) described in this embodiment is manufactured by a method including the following steps.
Note that the manufacturing method of the light emitting device 021 (22) is different from the manufacturing method of the light emitting device 222 (22) in that: in the step of forming the layer 111, mCBP is used instead of mpczptzn-02 as a host material; and as luminescent material FM TTPA was used instead of 2Ph-mmtBuDPhA2Anth. The differences will be described in detail herein, and the above description is applied to portions using the same method.
[ fourth step ]
In a fourth step, layer 111 is formed on layer 112. Specifically, the material is co-evaporated by a resistance heating method.
Note that layer 111 comprises mCBP, ir (5 tBuppy) 3 And TTPA, the weight ratio of which is mCBP: ir (5 tBuppy) 3 : ttpa=1: 0.1:0.05, and the thickness thereof was 40nm (see Table 3).
Reference example 2
The reference device 1 manufactured as described in this reference example has the same structure as the light-emitting device 150 (see fig. 17A).
The light emitting device 150 includes an electrode 101, an electrode 102, and a layer 111. Electrode 102 includes an area overlapping electrode 101 with layer 111 between electrode 101 and electrode 102. In addition, light emitting device 150 includes layer 104 and layer 105.
The layer 111 contains a host material having a function of emitting delayed fluorescence at room temperature.
Structure of reference device 1
Table 6 shows the structure of the reference device 1. In addition, the structural formula of the material used for the reference device described in this embodiment is shown below.
TABLE 6
Reference device 1 manufacturing method-
The reference device 1 described in this embodiment is manufactured by a method including the following steps.
[ first step ]
In a first step, the electrode 101 is formed. Specifically, the electrode 101 is formed by a sputtering method using indium oxide-tin oxide (abbreviated as ITSO) containing silicon or silicon oxide as a target.
Note that the electrode 101 contains ITSO with a thickness of 70nm and an area of 4mm 2 (2mm×2mm)。
Next, the substrate on which the electrode 101 was formed was washed with water, baked at 200 ℃ for 1 hour, and then subjected to UV ozone treatment for 370 seconds. Then, the substrate was put into the inside thereof and depressurized to 10 -4 In a vacuum vapor deposition apparatus of the order Pa, vacuum baking is performed at 170℃for 30 minutes in a heating chamber in the vacuum vapor deposition apparatus. Then, the substrate was cooled for about 30 minutes.
[ second step ]
In a second step, layer 104 is formed on electrode 101. Specifically, the material is co-evaporated by a resistance heating method.
Note that layer 104 includes DBT3P-II and MoO 3 The weight ratio of the DBT3P-II is as follows: moO (MoO) 3 =1: 0.5, the thickness of which is 30nm.
Third step
In a third step, layer 112 is formed over layer 104. Specifically, the material is deposited by a resistance heating method.
Note that layer 112 contains 3,3' -bis (9-phenyl-9H-carbazole) (PCCP for short) with a thickness of 20nm.
[ fourth step ]
In a fourth step, layer 111 is formed on layer 112. Specifically, the material is deposited by a resistance heating method.
Note that layer 111 comprises mpczptzn-02, which has a thickness of 30nm.
[ fifth step ]
In a fifth step, layer 113A is formed over layer 111. Specifically, the material is deposited by a resistance heating method.
Note that layer 113A comprises mpczptzn-02, which has a thickness of 20nm.
Sixth step
In the sixth step, layer 113B is formed on layer 113A. Specifically, the material is deposited by a resistance heating method.
Note that layer 113B contains 2, 9-bis (naphthalen-2-yl) -4, 7-diphenyl-1, 10-phenanthroline (abbreviated as NBPhen) with a thickness of 10nm.
Seventh step
In a seventh step, layer 105 is formed over layer 113B. Specifically, the material is deposited by a resistance heating method.
Note that layer 105 comprises LiF, which has a thickness of 1nm.
[ eighth step ]
In an eighth step, the electrode 102 is formed on the layer 105. Specifically, the material is deposited by a resistance heating method.
Note that the electrode 102 contains Al, which has a thickness of 200nm.
Reference device 1 operating characteristics-
The reference device 1 emits light EL1 when supplied with power (refer to fig. 17A). The operation characteristics of the reference device 1 were measured (see fig. 29 and 30). Note that at room temperature, luminance and CIE chromaticity were measured with a color luminance meter (BM-5A manufactured by topukang corporation), and emission spectrum was measured with a multichannel spectrum analyzer (PMA-11 manufactured by japan bingo photonics corporation).
In addition, delayed fluorescence was measured using a picosecond fluorescence lifetime measurement system (manufactured by the division of the Japanese Kokai Song photonics Co.). Specifically, it will be equivalent to 1300cd/m 2 The voltage of the condition of (2) is applied to the reference device 1, a predetermined voltage is held in a rectangular pulse shape during 100 mus, and decay of delayed fluorescence is observed during 20 mus. In addition, negative bias of-5V was applied during the period in which the decay of delayed fluorescence was observed. The measurement was repeated with a cycle of 10Hz, and the data were accumulated. Fig. 31 shows the light emission intensity of the reference device 1 pulse-driven at a predetermined voltage.
The holes supplied from the electrode 101 and the electrons supplied from the electrode 102 are recombined in the layer 111, and light emission is obtained from the host material in the excited state generated, specifically, light emission is obtained from mpczptzn-02 in the excited state (see fig. 30). In addition, at least light emission from excitons having a short lifetime of 0.3 μs or less and light emission from excitons having a long lifetime of 6 μs can be confirmed (see fig. 31). This confirmed that singlet excitons are generated via triplet excitons having a long lifetime.
Example 2
In this embodiment, the light emitting devices 321 (22) to 332 (22) according to one embodiment of the present invention are described with reference to fig. 17 and 32 to 38. Note that, for convenience, subscripts and superscripts are recited in the drawings and tables of this embodiment to standard sizes. For example, the subscripts in the abbreviations and the superscripts in the units are all described in the tables in standard sizes. The description in the above table may be replaced with the description in the specification.
Fig. 32 is a diagram illustrating current density-luminance characteristics of the light emitting devices 321 (22) and 331 (22).
Fig. 33 is a diagram illustrating luminance-current efficiency characteristics of the light emitting devices 321 (22) and 331 (22).
Fig. 34 is a diagram illustrating voltage-luminance characteristics of the light emitting devices 321 (22) and 331 (22).
Fig. 35 is a diagram illustrating voltage-current characteristics of the light emitting device 321 (22) and the light emitting device 331 (22).
Fig. 36 is a diagram illustrating luminance-external quantum efficiency characteristics of the light emitting devices 321 (22) and 331 (22). Note that, assuming that the light distribution characteristic of the light emitting device is lambertian, the external quantum efficiency is calculated from the luminance.
FIG. 37 is a view showing the light-emitting devices 321 (22) and 331 (22) at 1000cd/m 2 Is a graph of an emission spectrum when the luminance of the light is emitted.
FIG. 38 is a graph illustrating the flow rate of 50mA/cm 2 A graph of normalized luminance versus time characteristics when the light emitting devices 321 (22) and 331 (22) emit light.
< light-emitting device 321 (22) >)
The light-emitting device 321 (22) manufactured as described in this embodiment has the same structure as the light-emitting device 150 (see fig. 17A).
The light-emitting device 150 includes an electrode 101, an electrode 102, and a layer 111 (see fig. 17A). Electrode 102 includes an area overlapping electrode 101 with layer 111 between electrode 101 and electrode 102.
The layer 111 comprises a luminescent material FM, an energy donor material ED and a host material.
The luminescent material FM has a function of emitting fluorescence, and has an end located at the longest wavelength of the absorption spectrum Abs at the wavelength λabs (nm) (see fig. 17C).
Use of an organometallic complex as energy donor material ED, the organometallic complex comprising a ligand comprising a substituent R 1 Substituent R 1 Is any of alkyl, cycloalkyl and trialkylsilyl groups. Note that the number of carbon atoms of the alkyl group is 3 or more and 12 or less, the number of ring-forming carbon atoms of the cycloalkyl group is 3 or more and 10 or less, and the number of carbon atoms of the trialkylsilyl group is 3 or more and 12 or less.
In addition, the organometallic complex has a function of emitting phosphorescence at room temperature, the phosphorescence having an end portion located at the shortest wavelength of the spectrum at a wavelength λp (nm), the wavelength λp being located at a short wavelength compared to the wavelength λabs.
The organometallic complex has a first HOMO level HOMO1 and a first LUMO level LUMO1 (see fig. 17B).
The host material has a function of emitting delayed fluorescence at room temperature, and has a second HOMO level HOMO2 and a second LUMO level LUMO2.
The first HOMO level HOMO1, the first LUMO level LUMO1, the second HOMO level HOMO2, and the second LUMO level LUMO2 satisfy the following expression (1).
[ calculation formula 8]
(LUMO2-HOMO2)＜(LUMO1-HOMO1)···(1)
Structure of light-emitting device 321 (22)
Table 7 shows the structure of the light emitting device 321 (22). In addition, the structural formula of the material used for the light emitting device described in this embodiment, and the HOMO level and LUMO level are shown below.
The TTPA of the light-emitting material FM for the light-emitting device 321 (22) has an end portion located at the longest wavelength of the absorption spectrum at a wavelength of 514nm (refer to fig. 18). Note that the absorption spectrum of the luminescent material FM in a toluene solution was measured at room temperature using an ultraviolet-visible spectrophotometer (model V550 manufactured by japan spectroscopy).
Ir (5 tBuppy) of organometallic complex for light-emitting device 321 (22) 3 Has the function of emitting phosphorescence. The phosphorescence has an end at the wavelength 484nm at the shortest wavelength of the spectrum, which end is at a short wavelength compared to the wavelength 514 nm. In addition, ir (5 tBuppy) 3 Has a first HOMO level HOMO1 at-5.32 eV and a first LUMO level LUMO1 at-2.25 eV. Note that measurement of phosphorescence spectrum of the organometallic complex in methylene chloride solution was performed using a fluorescence spectrophotometer (model FP-8600 manufactured by japan spectroscopy corporation) at room temperature. The HOMO and LUMO levels of the organometallic complex were calculated from oxidation and reduction potentials obtained by Cyclic Voltammetry (CV) measurement using an electrochemical analyzer (model: ALS 600A or 600C, manufactured by BAS Co., ltd.).
The mixed material of the host materials for the light emitting device 321 (22) has a function of emitting delayed fluorescence. Specifically, a mixed material comprising mpczptzn-02 and PCCP emits delayed fluorescence. The mixed material had a second HOMO level HOMO2 at-5.63 eV and a second LUMO level LUMO2 at-3.00 eV (see table 2). Note that the HOMO level and LUMO level of the host material were calculated from oxidation potential and reduction potential obtained by Cyclic Voltammetry (CV) measurement using an electrochemical analyzer (model: ALS 600A or 600C, manufactured by BAS corporation).
Note that the value of (LUMO 2-HOMO 2) is 2.63eV, which is smaller than the value of (LUMO 1-HOMO 1), i.e., 3.07eV.
TABLE 7
< method of manufacturing light-emitting device 321 (22) >
The light emitting device 321 (22) described in this embodiment is manufactured by a method including the following steps.
[ first step ]
In a first step, the electrode 101 is formed. Specifically, the electrode 101 is formed by a sputtering method using indium oxide-tin oxide (abbreviated as ITSO) containing silicon or silicon oxide as a target.
Note that the electrode 101 contains ITSO with a thickness of 70nm and an area of 4mm 2 (2mm×2mm)。
Next, the substrate on which the electrode 101 was formed was washed with water, baked at 200 ℃ for 1 hour, and then subjected to UV ozone treatment for 370 seconds. Then, the substrate was put into the inside thereof and depressurized to 10 -4 In a vacuum vapor deposition apparatus of the order Pa, vacuum baking is performed at 170℃for 30 minutes in a heating chamber in the vacuum vapor deposition apparatus. Then, the substrate was cooled for about 30 minutes.
[ second step ]
In a second step, layer 104 is formed on electrode 101. Specifically, the material is co-evaporated by a resistance heating method.
Note that layer 104 includes DBT3P-II and MoO 3 The weight ratio of the DBT3P-II is as follows: moO (MoO) 3 =1: 0.5, the thickness of which is 40nm.
Third step
In a third step, layer 112 is formed over layer 104. Specifically, the material is deposited by a resistance heating method.
Note that layer 112 comprises 4,4' -diphenyl-4 "- (9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviated as pcbi 1 BP) having a thickness of 20nm.
[ fourth step ]
In a fourth step, layer 111 is formed on layer 112. Specifically, the material is co-evaporated by a resistance heating method.
Note that layer 111 comprises mpczptzn-02, PCCP, ir (5 tBuppy) 3 And TTPA, the weight ratio of which is mPCzPTzn-02: PCCP: ir (5 tBuppy) 3 : ttpa=0.5: 0.5:0.1:0.05, with a thickness of 40nm. Note that mPCCzPTzn-02 and PCCP are exciplex forming substances.
TABLE 8
[ fifth step ]
In a fifth step, layer 113A is formed over layer 111. Specifically, the material is deposited by a resistance heating method.
Note that layer 113A comprises mpczptzn-02, which has a thickness of 20nm.
Sixth step
In the sixth step, layer 113B is formed on layer 113A. Specifically, the material is deposited by a resistance heating method.
Note that layer 113B comprises NBPhen, which is 10nm thick.
Seventh step
In a seventh step, layer 105 is formed over layer 113B. Specifically, the material is deposited by a resistance heating method.
Note that layer 105 comprises LiF, which has a thickness of 1nm.
[ eighth step ]
In an eighth step, the electrode 102 is formed on the layer 105. Specifically, the material is deposited by a resistance heating method.
Note that the electrode 102 contains Al, which has a thickness of 200nm.
< light-emitting device 331 (22) >)
The light-emitting device 331 (22) manufactured as described in this embodiment has the same structure as the light-emitting device 150 (see fig. 17A).
Structure of light-emitting device 331 (22)
The light-emitting device 331 (22) is different from the light-emitting device 321 (22) in that tris [2- [4- (tert-butyl) -2-pyridyl- κN ] is used as the energy donor material ED]Phenyl-kappa C]Iridium (abbreviated as Ir (4 tBuuppy) 3 )。
Ir (4 tBuppy) of organometallic complex for light-emitting device 331 (22) 3 Has a function of emitting phosphorescence (refer to fig. 19). The phosphorescence has an end at the shortest wavelength of the spectrum at wavelength 482nm that is at a short wavelength compared to wavelength 514 nm. In addition, ir (4 tBuuppy) 3 Has a first HOMO level HOMO1 at-5.26 eV and a first LUMO level LUMO1 at-2.25 eV. Note that measurement of phosphorescence spectrum of the organometallic complex in methylene chloride solution was performed using a fluorescence spectrophotometer (model FP-8600 manufactured by japan spectroscopy corporation) at room temperature. In addition, organometallic complexes The HOMO and LUMO levels of (C) were calculated from oxidation and reduction potentials obtained by Cyclic Voltammetry (CV) measurement using an electrochemical analyzer (model: ALS 600A or 600C, manufactured by BAS Co., ltd.).
Note that the value of (LUMO 2-HOMO 2) is 2.63eV, which is smaller than the value of (LUMO 1-HOMO 1), i.e., 3.01eV.
< method of manufacturing light-emitting device 331 (22) >)
The light emitting device 331 (22) described in this embodiment is manufactured by a method including the following steps.
Note that the manufacturing method of the light emitting device 331 (22) is different from the manufacturing method of the light emitting device 321 (22) in that: in the step of forming the layer 111, ir (4 tBuppy) is used as the energy donor material ED 3 Instead of Ir (5 tBuuppy) 3 . The differences will be described in detail herein, and the above description is applied to portions using the same method.
[ fourth step ]
In a fourth step, layer 111 is formed on layer 112. Specifically, the material is co-evaporated by a resistance heating method.
Note that layer 111 comprises mpczptzn-02, PCCP, ir (4 tBuppy) 3 And TTPA, the weight ratio of which is mPCzPTzn-02: PCCP: ir (4 tBuppy) 3 : ttpa=0.5: 0.5:0.1:0.05, and the thickness thereof was 40nm (see Table 8).
< operating characteristics of light emitting device 321 (22) and light emitting device 331 (22 >)
The light emitting device 321 (22) and the light emitting device 331 (22) emit green light EL1 when power is supplied (see fig. 17A). The operating characteristics of the light emitting devices 321 (22) and 331 (22) are measured (see fig. 32 to 37). Note that the luminance, CIE chromaticity, and emission spectrum were measured at room temperature using a spectroradiometer (SR-UL 1R manufactured by trapkang).
Table 4 shows that the light-emitting device manufactured was made to be 1000cd/m 2 The main initial characteristics of the left and right luminance light emission. In addition, table 4 shows LT90, which means that the temperature of the alloy at a constant current density (50 mA/cm 2 ) The time elapsed until the luminance was reduced to 90% of the initial luminance when the light-emitting device was caused to emit light. In addition, table 4 also shows characteristics of other light emitting devices, and their structures will be described below.
It can be seen that the light emitting device 321 (22) and the light emitting device 331 (22) exhibit good characteristics. For example, the light emitting device 321 (22) and the light emitting device 331 (22) emit light having an emission spectrum from the light emitting material FM with a peak wavelength at about 540nm (see fig. 37). In addition, no luminescence from the energy donor material ED was observed. Alternatively, energy is transferred from the energy donor material ED to the luminescent material FM. In addition, undesired energy transfer from the energy donor material ED to the luminescent material FM can be suppressed. In addition, energy transfer based on the tex mechanism can be suppressed.
In addition, the light emitting device 321 (22) and the light emitting device 331 (22) can realize 1000cd/m at a lower voltage than the comparison device 311 (22) 2 Left and right brightness (see table 4). In addition, higher external quantum efficiency is exhibited compared to the comparison device 311 (22).
In addition, at 50mA/cm 2 When the light-emitting device emits light, the time required for the luminance of the light-emitting device 321 (22) and the light-emitting device 331 (22) to decrease to 90% of the initial luminance is longer than that of the comparison device 311 (22).
Reference example 3
The comparison device 311 (22) manufactured as described in this reference example is different from the light emitting device 321 (22) and the light emitting device 331 (22) in that tris (2-phenylpyridyl-N, C) is used as the energy donor material ED 2 ' iridium (III) (abbreviation: ir (ppy) 3 )。
Structure of comparison device 311 (22)
The comparison device 311 (22) manufactured as described in this reference example is different from the light-emitting device 321 (22) in that Ir (ppy) is used as the energy donor material ED 3 。
Ir (ppy) of organometallic complex for light-emitting device 311 (22) 3 Including ligands. Note that the ligand does not include alkyl, cycloalkyl, or trialkylsilyl groups.
[ chemical formula 22]
Method for manufacturing comparison device 311 (22)
The comparison device 311 (22) is manufactured by a method including the following steps.
Note that the manufacturing method of the comparison device 311 (22) is different from the manufacturing method of the light emitting device 321 (22) in that: ir (ppy) is used as energy donor material ED in the step of forming layer 111 3 Instead of Ir (5 tBuuppy) 3 . The differences will be described in detail herein, and the above description is applied to portions using the same method.
[ fourth step ]
In a fourth step, layer 111 is formed on layer 112. Specifically, the material is co-evaporated by a resistance heating method.
Note that layer 111 comprises mpczptzn-02, PCCP, ir (ppy) 3 And TTPA, the weight ratio of which is mPCzPTzn-02: PCCP: ir (ppy) 3 : ttpa=0.5: 0.5:0.1:0.05 (weight ratio) and the thickness thereof was 40nm (see Table 8).
Reference example 4
The reference device 2 manufactured as described in this reference example differs from the reference device 1 in the structure of the layer 111, specifically, not only mpczptzn-02 but also a mixed material containing mpczptzn-02 and PCCP is used as a host material.
Reference device 2 manufacturing method-
The reference device 2 described in this embodiment is manufactured by a method including the following steps.
Note that in the step of forming the layer 111, the manufacturing method of the reference device 2 is different from the manufacturing method of the reference device 1. The differences will be described in detail herein, and the above description is applied to portions using the same method.
[ fourth step ]
In a fourth step, layer 111 is formed on layer 112. Specifically, the material is deposited by a resistance heating method.
Note that layer 111 comprises mpczptzn-02 and PCCP in a weight ratio of mpczptzn-02: pccp=0.8: 0.2, the thickness of which is 30nm.
Reference device 2 operating characteristics-
The reference device 2 emits light EL1 when supplied with power (refer to fig. 17A). The reference device 2 is subjected to operation characteristics (see fig. 29 and 30). Note that a color luminance meter (BM-5A manufactured by topukang corporation) was used in the measurement of luminance and CIE chromaticity, and a multichannel spectrum analyzer (PMA-11 manufactured by japan bingo photonics corporation) was used as the measurement of emission spectrum at room temperature.
In addition, delayed fluorescence was measured using a picosecond fluorescence lifetime measurement system (manufactured by the division of the Japanese Kokai Song photonics Co.). Specifically, it will be equivalent to 1300cd/m 2 The voltage of the condition of (2) is applied to the reference device, a predetermined voltage is held in a rectangular pulse shape during 100 mus, and the decay of the delayed fluorescence is observed during 20 mus. In addition, negative bias of-5V was applied during the period in which the decay of delayed fluorescence was observed. The measurement was repeated with a cycle of 10Hz, and the data were accumulated. Fig. 31 shows the light emission intensity of the reference device 2 pulse-driven at a predetermined voltage.
Holes supplied from the electrode 101 and electrons supplied from the electrode 102 are recombined in the layer 111, and light emission is obtained from the host material in the excited state generated, specifically, light emission is obtained from the exciplex of mpczptzn-02 and PCCP (see fig. 30). In addition, at least light emission from excitons having a short lifetime of 0.3 μs or less and light emission from excitons having a long lifetime of 4 μs can be confirmed (see fig. 31). This confirmed that singlet excitons are generated via triplet excitons having a long lifetime.
Example 3
In this embodiment, the light emitting devices 322 (22) to 332 (22) according to one embodiment of the present invention are described with reference to fig. 17 and 39 to 45. Note that, for convenience, subscripts and superscripts are recited in the drawings and tables of this embodiment to standard sizes. For example, the subscripts in the abbreviations and the superscripts in the units are all described in the tables in standard sizes. The description in the above table may be replaced with the description in the specification.
Fig. 39 is a diagram illustrating current density-luminance characteristics of the light emitting device 322 (22) and the light emitting device 332 (22).
Fig. 40 is a diagram illustrating luminance-current efficiency characteristics of the light emitting device 322 (22) and the light emitting device 332 (22).
Fig. 41 is a diagram illustrating voltage-luminance characteristics of the light emitting device 322 (22) and the light emitting device 332 (22).
Fig. 42 is a diagram illustrating voltage-current characteristics of the light emitting device 322 (22) and the light emitting device 332 (22).
Fig. 43 is a diagram illustrating luminance-external quantum efficiency characteristics of the light emitting device 322 (22) and the light emitting device 332 (22). Note that, assuming that the light distribution characteristic of the light emitting device is lambertian, the external quantum efficiency is calculated from the luminance.
FIG. 44 is a view illustrating the light-emitting device 322 (22) and the light-emitting device 332 (22) at 1000cd/m 2 Is a graph of an emission spectrum when the luminance of the light is emitted.
FIG. 45 is a graph illustrating the flow rate of 50mA/cm 2 A graph of normalized luminance versus time characteristics when light emitting devices 322 (22) and 332 (22) emit light.
< light-emitting device 322 (22) >)
The light-emitting device 322 (22) manufactured as described in this embodiment has the same structure as the light-emitting device 150 (see fig. 17A). Note that the light-emitting device 322 (22) is different from the light-emitting device 321 (22) in that 2 Ph-mmtbudppa 2Anth is used as the light-emitting material FM.
The luminescent material FM comprises a second substituent R 2 A second substituent R 2 Is any one of methyl, alkyl having a branched chain, substituted or unsubstituted cycloalkyl and trialkylsilyl. Note that the branched alkyl group has 3 to 12 carbon atoms, the cyclic carbon atom of the cycloalkyl group has 3 to 10 carbon atoms, and the trialkylsilyl group has 3 to 12 carbon atoms.
Structure of light-emitting device 322 (22)
The light-emitting device 322 (22) manufactured as described in this embodiment is different from the light-emitting device 321 (22) in that 2 Ph-mmtbudppa 2Anth is used as the light-emitting material FM.
The 2 Ph-mmtbudppa 2Anth of the light emitting material FM for the light emitting device 322 (22) has an end located at the longest wavelength of the absorption spectrum at wavelength 519nm (refer to fig. 20).
Ir (5 tBuppy) organometallic complex for a light-emitting device 322 (22) 3 Has the function of emitting phosphorescence. The phosphorescence has an end portion at the shortest wavelength of the spectrum at wavelength 484nm, which end portion is at a short wavelength compared to wavelength 519 nm.
Method for manufacturing light-emitting device 322 (22)
The light emitting device 322 (22) is manufactured using a method including the following steps.
Note that the manufacturing method of the light emitting device 322 (22) is different from the manufacturing method of the light emitting device 321 (22) in that: in the step of forming layer 111, 2 Ph-mmtbudppa 2Anth was used as the light-emitting material FM instead of TTPA. The differences will be described in detail herein, and the above description is applied to portions using the same method.
[ fourth step ]
In a fourth step, layer 111 is formed on layer 112. Specifically, the material is co-evaporated by a resistance heating method.
Note that layer 111 comprises mpczptzn-02, PCCP, ir (5 tBuppy) 3 And 2Ph-mmtBuDPhA2Anth in the weight ratio of mPCzPTzn-02: PCCP: ir (5 tBuppy) 3 :2 Ph-mmtbudppa2anth=0.5: 0.5:0.1:0.05, with a thickness of 40nm.
TABLE 9
< light-emitting device 332 (22) >)
The light emitting device 332 (22) manufactured as described in this embodiment has the same structure as the light emitting device 150 (see fig. 17A). Note that the light emitting device 332 (22) is different from the light emitting device 321 (22) in that: ir (4 tBuppy) was used as energy donor material ED 3 The method comprises the steps of carrying out a first treatment on the surface of the And as the luminescent material FM, 2Ph-mmtBuDPhA2Anth was used.
Structure of light emitting device 332 (22)
The light emitting device 332 (22) manufactured as described in this embodiment is different from the light emitting device 321 (22) in that: ir (4 tBuppy) was used as energy donor material ED 3 As the luminescent material FM, 2Ph-mmtBuDPhA2Anth was used.
The 2 Ph-mmtbudppa 2Anth of the light-emitting material FM for the light-emitting device 332 (22) has an end located at the longest wavelength of the absorption spectrum at wavelength 519nm (refer to fig. 21).
Ir (4 tBuppy) organometallic complex for a light-emitting device 332 (22) 3 Has the function of emitting phosphorescence. The phosphorescence has an end at the shortest wavelength of the spectrum at wavelength 482nm that is at a short wavelength compared to wavelength 519 nm. In addition, ir (4 tBuuppy) 3 Has a first HOMO level HOMO1 at-5.26 eV and a first LUMO level LUMO1 at-2.25 eV.
Note that the value of (LUMO 2-HOMO 2) is 2.63eV, which is smaller than the value of (LUMO 1-HOMO 1), i.e., 3.01eV.
Method for manufacturing light-emitting device 332 (22)
The light emitting device 332 (22) described in this embodiment is manufactured by a method including the following steps.
Note that the manufacturing method of the light emitting device 332 (22) is different from the manufacturing method of the light emitting device 321 (22) in that: in the step of forming the layer 111, ir (4 tBuppy) is used as the energy donor material ED 3 Instead of Ir (5 tBuuppy) 3 As luminescent material FM, 2Ph-mmtBuDPhA2Anth was used instead of TTPA. The differences will be described in detail herein, and the above description is applied to portions using the same method.
[ fourth step ]
In a fourth step, layer 111 is formed on layer 112. Specifically, the material is co-evaporated by a resistance heating method.
Note that layer 111 comprises mpczptzn-02, PCCP, ir (4 tBuppy) 3 And 2Ph-mmtBuDPhA2Anth in the weight ratio of mPCzPTzn-02: PCCP: ir (4 tBuppy) 3 :2 Ph-mmtbudppa2anth=0.5: 0.5:0.1:0.05, and the thickness thereof was 40nm (see Table 9).
< operating characteristics of light emitting device 322 (22) and light emitting device 332 (22 >)
The light emitting device 322 (22) and the light emitting device 332 (22) emit green light EL1 when power is supplied (see fig. 17A). The operating characteristics of the light emitting device 322 (22) and the light emitting device 332 (22) are measured (see fig. 39 to 44). Note that the luminance, CIE chromaticity, and emission spectrum were measured at room temperature using a spectroradiometer (SR-UL 1R manufactured by trapkang).
Table 4 shows that the light-emitting devices 322 (22) and 332 (22) were set to 1000cd/m 2 The main initial characteristics of the left and right luminance light emission. In addition, table 4 shows LT90, which means that the temperature of the alloy at a constant current density (50 mA/cm 2 ) The elapsed time from the reduction of the luminance to 90% of the initial luminance when the light-emitting device emits light was reduced.
It can be seen that light emitting device 322 (22) and light emitting device 332 (22) exhibit good characteristics. For example, the light emitting device 322 (22) and the light emitting device 332 (22) emit light having an emission spectrum from the light emitting material FM with a peak wavelength at about 540nm (see fig. 44). In addition, no luminescence from the energy donor material ED was observed. Alternatively, energy is transferred from the energy donor material ED to the luminescent material FM. In addition, undesired energy transfer from the energy donor material ED to the luminescent material FM can be suppressed. In addition, energy transfer based on the tex mechanism can be suppressed.
In addition, the light emitting devices 322 (22) and 332 (22) may be implemented at a voltage 1000cd/m lower than the voltage of the comparing device 312 (22) 2 Left and right brightness (see table 4). In addition, higher external quantum efficiency is exhibited compared to the comparison device 312 (22).
In addition, at 50mA/cm 2 When the light emitting device emits light, the time required for the normalized luminance of the light emitting device 322 (22) and the light emitting device 332 (22) to decrease to 90% of the initial luminance is longer than that of the comparison device 312 (22), and the reliability is higher (see fig. 45).
Compared with the existing light emitting device, the light emitting device of one embodiment of the present invention can realize high reliability in an environment of 65 ℃. For example, it is expected to realize a light emitting device B having reliability that the light emitting device B is emitting greenLight emitting device of colored light at 29000cd/m 2 When the left and right luminance is emitted, the time elapsed until the luminance is reduced to 90% of the initial luminance is about twice that of the conventional light emitting device a (see fig. 46).
Reference example 5
The comparison device 312 (22) manufactured as described in this reference example is different from the light emitting device 322 (22) and the light emitting device 332 (22) in that tris (2-phenylpyridyl-N, C) is used as the energy donor material ED 2 ' iridium (III) (abbreviation: ir (ppy) 3 )。
< Structure of comparison device 312 (22) ]
In the comparison device 312 (22) manufactured as described in this reference example, ir (ppy) was used as the energy donor material ED 3 。
Structure of comparison device 312 (22)
In the comparison device 312 (22) manufactured as described in this reference example, ir (ppy) was used as the energy donor material ED 3 。
Method for manufacturing comparison device 312 (22) >
The comparison device 312 (22) is manufactured using a method including the following steps.
Note that the manufacturing method of the comparison device 312 (22) is different from the manufacturing method of the light emitting device 321 (22) in that: ir (ppy) is used as energy donor material ED in the step of forming layer 111 3 Instead of Ir (5 tBuuppy) 3 As luminescent material FM, 2Ph-mmtBuDPhA2Anth was used instead of TTPA. The differences will be described in detail herein, and the above description is applied to portions using the same method.
[ fourth step ]
In a fourth step, layer 111 is formed on layer 112. Specifically, the material is co-evaporated by a resistance heating method.
Note that layer 111 comprises mpczptzn-02, PCCP, ir (ppy) 3 And 2Ph-mmtBuDPhA2Anth in the weight ratio of mPCzPTzn-02: PCCP: ir (ppy) 3 :2 Ph-mmtbudppa2anth=0.5: 0.5:0.1:0.05, and the thickness thereof was 40nm (see Table 9).
[ description of the symbols ]
101: electrode, 101S: electrode, 102: electrode, 103: unit, 103S: unit, 104: layer, 105: layer, 106: intermediate layer, 106A: layer, 106B: layer, 111: layer, 112: layer, 113: layer, 113A: layer, 113B: layer, 114: layer, 114N: layer, 114P: layer, 150: light emitting device, 170: optical function device, 400: substrate, 401: electrode, 403: EL layer, 404: electrode, 405: sealant, 406: sealant, 407: sealing substrate, 412: pad, 420: IC chip, 521: insulating film, 528: insulating film, 573: insulating film, 573A: insulating film, 573B: insulating film, 601: source line driving circuit, 602: pixel portion 603: gate line driving circuit, 604: sealing substrate, 605: sealant, 607: space, 608: wiring, 609: FPC, 610: element substrate, 611: switching FET, 612: current control FETs, 613: electrode, 614: insulation, 616: EL layer, 617: electrode, 618: light emitting device, 623: FET, 700: functional panel, 951: substrate 952: electrode, 953: insulating layer 954: isolation layer, 955: EL layer, 956: electrode, 1001: substrate, 1002: base insulating film, 1003: gate insulating film, 1006: gate electrode, 1007: gate electrode, 1008: gate electrode, 1020: interlayer insulating film 1021: interlayer insulating film 1022: electrode, 1024B: electrode, 1024G: electrode, 1024R: electrode, 1024W: electrode, 1025: partition wall, 1028: EL layer, 1029: electrode, 1031: sealing substrate, 1032: sealant, 1033: substrate, 1034B: coloring layer, 1034G: coloring layer, 1034R: coloring layer, 1035: black matrix, 1036: protective layer, 1037: interlayer insulating film, 1040: pixel unit, 1041: drive circuit portion 1042: peripheral portion, 2001: frame body, 2002: light source, 2100: robot, 2101: illuminance sensor 2102: microphone, 2103: upper camera, 2104: speaker, 2105: display, 2106: lower camera, 2107: obstacle sensor, 2108: movement mechanism, 2110: arithmetic device, 3001: lighting device, 5000: frame body, 5001: display unit, 5002: display unit, 5003: speaker, 5004: LED lamp, 5006: connection terminal, 5007: sensor, 5008: microphone, 5012: support portion 5013: earphone, 5100: sweeping robot 5101: display, 5102: camera 5103: brush 5104: operation button, 5120: garbage, 5140: portable electronic device, 5200: display area, 5201: display area, 5202: display area, 5203: display area, 7101: frame body, 7103: display unit, 7105: support, 7107: display unit, 7109: operation key, 7110: remote control operation machine, 7201: main body, 7202: frame, 7203: display unit, 7204: keyboard, 7205: external connection port, 7206: pointing device, 7210: display unit 7401: frame body, 7402: display portion 7403: operation button, 7404: external connection port, 7405: speaker, 7406: microphone, 9310: portable information terminal, 9311: display panel, 9313: hinge portion, 9315: frame body

Claims (13)

1. A light emitting device, comprising:
a first electrode;
a second electrode; and
the first layer of the material is formed from a first layer,
wherein the second electrode includes a region overlapping the first electrode,
the first layer is located between the first electrode and the second electrode,
the first layer comprises a luminescent material, a first organic compound and a first material,
the luminescent material has the function of emitting fluorescence,
the luminescent material has an end at a first wavelength located at a longest wavelength of an absorption spectrum,
the first organic compound has a function of converting triplet excitation energy into luminescence,
the luminescence of the first organic compound has an end at the shortest wavelength of the spectrum at the second wavelength,
the second wavelength is at a short wavelength compared to the first wavelength,
the first organic compound includes a first substituent,
the first substituent is any one of alkyl, substituted or unsubstituted cycloalkyl and trialkylsilyl,
the alkyl group has 3 to 12 carbon atoms,
the cyclic carbon number of the cycloalkyl group is 3 or more and 10 or less,
the trialkylsilyl group has 3 to 12 carbon atoms,
and, the first material has a function of emitting delayed fluorescence at room temperature.
2. A light emitting device, comprising:
a first electrode;
a second electrode; and
the first layer of the material is formed from a first layer,
wherein the second electrode includes a region overlapping the first electrode,
the first layer is located between the first electrode and the second electrode,
the first layer comprises a luminescent material, a first organic compound and a first material,
the luminescent material has the function of emitting fluorescence,
the luminescent material has an end at a first wavelength located at a longest wavelength of an absorption spectrum,
the first organic compound has a function of converting triplet excitation energy into luminescence,
the luminescence of the first organic compound has an end at the shortest wavelength of the spectrum at the second wavelength,
the second wavelength is at a short wavelength compared to the first wavelength,
the first organic compound includes a first substituent,
the first substituent is any one of alkyl, substituted or unsubstituted cycloalkyl and trialkylsilyl,
the alkyl group has 3 to 12 carbon atoms,
the cyclic carbon number of the cycloalkyl group is 3 or more and 10 or less,
the trialkylsilyl group has 3 to 12 carbon atoms,
the first material is composed of a second organic compound and a third organic compound,
And, the second organic compound and the third organic compound form an exciplex.
3. The light emitting device according to claim 1 or 2,
wherein the first organic compound has a first HOMO level HOMO1 and a first LUMO level LUMO1,
the first material having a second HOMO level HOMO2 and a second LUMO level LUMO2,
and the first HOMO level HOMO1, the first LUMO level LUMO1, the second HOMO level HOMO2, and the second LUMO level LUMO2 satisfy the following expression (1).
[ formula 1]
(LUMO2-HOMO2)＜(LUMO1-HOMO1)…(I)。
4. The light-emitting device according to any one of claim 1 to 3,
wherein the luminescent material comprises a second substituent,
the second substituent is any one of methyl, alkyl with a branched chain, substituted or unsubstituted cycloalkyl and trialkylsilyl,
the branched alkyl group has 3 to 12 carbon atoms,
the cyclic carbon number of the cycloalkyl group is 3 or more and 10 or less,
and the trialkylsilyl group has 3 to 12 carbon atoms.
5. The light-emitting device according to any one of claim 1 to 4,
wherein the luminescent material comprises more than five second substituents,
at least five of the second substituents of five or more are each independently any of a branched alkyl group, a substituted or unsubstituted cycloalkyl group, and a trialkylsilyl group,
The branched alkyl group has 3 to 12 carbon atoms,
the cyclic carbon number of the cycloalkyl group is 3 or more and 10 or less,
and the trialkylsilyl group has 3 to 12 carbon atoms.
6. The light-emitting device according to any one of claims 1 to 5,
wherein the luminescent material has a third LUMO energy level,
and the third LUMO level is higher than the second LUMO level LUMO 2.
7. The light-emitting device according to any one of claims 1 to 6,
wherein the second HOMO level HOMO2 is higher than the first HOMO level HOMO1,
and the second LUMO level LUMO2 is lower than the first LUMO level LUMO 1.
8. The light-emitting device according to any one of claims 1 to 6,
wherein the first HOMO level HOMO1 is higher than the second HOMO level HOMO 2.
9. The light-emitting device according to any one of claims 1 to 6,
wherein the first LUMO level LUMO1 is lower than the second LUMO level LUMO 2.
10. A light emitting device, comprising:
the light emitting device of any one of claims 1 to 9; and
a transistor or a substrate.
11. A display device, comprising:
the light emitting device of any one of claims 1 to 9; and
A transistor or a substrate.
12. A lighting device, comprising:
the light emitting device of claim 10; and
a frame body.
13. An electronic device, comprising:
the display device of claim 11; and
a sensor, an operating button, a speaker or a microphone. .
CN202280011221.1A 2021-01-28 2022-01-21 Light emitting device, light emitting apparatus, electronic apparatus, display apparatus, and lighting apparatus Pending CN116889119A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2021-012419 2021-01-28
JP2021-012819 2021-01-29
JP2021012819 2021-01-29
PCT/IB2022/050498 WO2022162508A1 (en) 2021-01-28 2022-01-21 Light emitting device, light emitting apparatus, electronic equipment, display apparatus, and lighting apparatus

Publications (1)

Publication Number Publication Date
CN116889119A true CN116889119A (en) 2023-10-13

Family

ID=88257342

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202280011221.1A Pending CN116889119A (en) 2021-01-28 2022-01-21 Light emitting device, light emitting apparatus, electronic apparatus, display apparatus, and lighting apparatus

Country Status (1)

Country Link
CN (1) CN116889119A (en)

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