CN108336238B - Organic light-emitting element using spirobifluorene ring compound - Google Patents

Abstract

An organic light-emitting element using a spirobifluorene ring compound comprises: an anode; at least two hole-assisting layers sequentially formed on the anode; a light-emitting layer formed on the at least two hole-assisting layers; at least one electron-assisting layer formed on the light-emitting layer; and a cathode formed on the electron-transporting layer, wherein at least one of the at least two hole-assisting layers contains a spirobifluorene ring compound of formula (I), and the hole-assisting layer formed in contact with the anode has a P-type doping compound or a compound of formula (II), so as to improve the performance of the organic light-emitting element.

Wherein, _G1 and _G2 are as defined in the specification.

Description

Organic light-emitting device using spirobifluorene compound

technical field

The present invention relates to an organic light-emitting element, in particular to an organic light-emitting element using a spirobifluorene ring compound.

Background technique

Organic light-emitting elements (OLEDs) are widely used in full-color displays or portable electronic devices because of their lightness, thinness, wide viewing angle, high contrast, low power consumption, high response speed, full-color images and flexibility. are highly anticipated.

A typical OLED is a multilayer thin film structure formed by sequentially depositing an anode, a hole transport layer, a light emitting layer, an electron transport layer and a cathode by a vacuum deposition method or a coating method. When a current is applied, the anode injects holes and the cathode injects electrons into the one or more organic layers, and the injected holes and electrons each migrate to the oppositely charged electrode. When electrons and holes are confined to the same molecule, an "exciton" is formed, the exciton has a confined electron-hole pair in an excited state, and the exciton relaxes and emits through a light-emitting mechanism Light.

In order to reduce the driving voltage of the existing OLED, a hole or electron injection layer is also provided, and a hole or electron blocking layer is added to improve the luminous efficiency. Therefore, the OLED has a multi-layer thin film structure to provide the element with good charge transport capability. , so, the key points to be considered in the device also need to include the interface stability between these electrodes and the organic layer and the matching between the corresponding organic materials. If the corresponding organic material is used in combination with the light-emitting layer as the hole and electron auxiliary layer, holes and electrons can be effectively transported to the light-emitting layer, the density of the electrons and holes in the light-emitting layer can be balanced, and the light-emitting efficiency can be increased.

It is disclosed in US7714145 that the use of spirobifluorene ring compounds in organic light-emitting elements can be an effective hole transport layer, but when different light-emitting layer materials are used, the luminous efficiency and driving voltage of the organic light-emitting element cannot meet the actual display. The application requirements, especially for automotive displays, the organic materials used in organic light-emitting elements need to have good thermal stability to maintain the elements in terms of luminous chromaticity, current efficiency, external quantum efficiency, luminous efficiency and service life. Require.

Therefore, there is an urgent need to develop an organic light-emitting device with improved device performance and extended service life to meet the needs of diverse applications.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an organic light-emitting element using a spirobifluorene ring compound, so as to improve the performance of the element such as current efficiency, external quantum efficiency, and luminous efficiency.

The present invention provides an organic light-emitting element using a spirobifluorene ring compound, comprising: an anode; at least two hole auxiliary layers sequentially formed on the anode, wherein at least two of the at least two hole auxiliary layers One layer contains the spirobifluorene compound of formula (I), and the hole auxiliary layer formed in contact with the anode has a P-type doping compound or a compound of formula (II); the light-emitting layer is formed in the at least two-layer space on the hole auxiliary layer; at least one electron auxiliary layer, formed on the light-emitting layer; and a cathode, formed on the electron auxiliary layer,

Wherein, G ₁ and G ₂ are the same or different, and G ₁ and G ₂ each independently represent the structure of formula (I-1) or formula (I-2):

wherein, B and R are the same or different, and B represents a C _6-30 aryl group, a C _5-30 heterocyclic group, a C _6-30 fused polycyclic aromatic hydrocarbon group, or contains O, S or N C _5-30 fused polycyclic aromatic hydrocarbon group of heteroatom, and R represents C _6-30 arylene group, C _5-30 heterocyclic group, divalent C _6-30 fused polycyclic aromatic hydrocarbon group or containing O , S or N heteroatom divalent C _5-30 fused polycyclic aromatic hydrocarbon group;

The organic light-emitting element using the spirobifluorene ring compound provided by the present invention passes through at least two hole auxiliary layers, wherein at least one layer of the at least two hole auxiliary layers contains the spirobifluorene ring of formula (I). compound, and the first hole auxiliary layer formed in contact with the anode has a P-type doping compound or a compound of formula (II), so as to improve the performance of the device.

Description of drawings

Embodiments of the invention are described by way of illustrative reference to the accompanying drawings:

1 is a schematic cross-sectional view of an embodiment of an organic light-emitting element provided by the present invention;

FIG. 2 is a schematic cross-sectional view of another embodiment of the organic light-emitting element provided by the present invention; and

FIG. 3 is a schematic cross-sectional view of another embodiment of the organic light-emitting element provided by the present invention.

Symbol Description

100, 200, 300 organic light-emitting elements

110 substrate

120 anode

130 The first hole auxiliary layer

140 Second hole auxiliary layer

145 The third hole auxiliary layer

150 light-emitting layers

155 Hole blocking layer

160 electron transport layer

170 Electron injection layer

180 cathodes.

Detailed ways

The embodiments of the present invention are described below through specific specific examples, and those skilled in the art can easily understand the advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different embodiments, and various details in this specification can also be given different modifications and changes based on different viewpoints and applications without departing from the spirit disclosed in the present invention. In addition, all ranges and values herein are inclusive and combinable. Any value or point falling within a range described herein, eg, any integer, can be taken as a minimum or maximum value to derive a lower range, etc.

The present invention provides an organic light-emitting element using a spirobifluorene ring compound, comprising: an anode; at least two hole auxiliary layers sequentially formed on the anode, wherein at least two of the at least two hole auxiliary layers One layer contains the spirobifluorene compound of formula (I), and the hole auxiliary layer formed in contact with the anode has a P-type doping compound or a compound of formula (II); the light-emitting layer is formed in the at least two-layer space on the hole auxiliary layer; at least one electron auxiliary layer, formed on the light-emitting layer; and a cathode, formed on the electron auxiliary layer,

Wherein, G ₁ and G ₂ are the same or different, and G ₁ and G ₂ each independently represent the structure of formula (I-1) or formula (I-2):

wherein, B and R are the same or different, and B represents a C _6-30 aromatic group, a C _5-30 heterocyclic group, a C _6-30 fused polycyclic aromatic hydrocarbon group, or contains O, S or N C _5-30 fused polycyclic aromatic hydrocarbon group of heteroatom, and R represents C _6-30 arylene group, C _5-30 heterocyclic group, divalent C _6-30 fused polycyclic aromatic hydrocarbon group or containing O , S or N heteroatom divalent C _5-30 fused polycyclic aromatic hydrocarbon group;

The hole auxiliary layer can be a hole injection layer, a hole transport layer or an electron blocking layer; similarly, the electron auxiliary layer can also be an electron injection layer, an electron transport layer or a hole blocking layer.

The P-type doping compound includes one selected from the group consisting of bismuth telluride, cadmium sulfide, cadmium selenide, gallium nitride, alkene compounds, titanium dioxide, zinc oxide and compounds of formula (II).

The structure of the organic light-emitting element of the present invention will be described with reference to the drawings.

1 is a schematic cross-sectional view of an embodiment of an organic light-emitting device of the present invention. The organic light-emitting device 100 includes: a substrate 110 ; an anode 120 ; a first hole assisting layer 130 and a second hole assisting layer formed on the anode 120 Layer 140, wherein at least one of the first hole assisting layer 130 and the second hole assisting layer 140 contains the spirobifluorene compound of formula (I), and the first hole assisting layer 130 has P-type doping A hetero compound or a compound of formula (II); a light-emitting layer 150 formed on the second hole assisting layer 140; an electron transport layer 160 and an electron injection layer 170 formed on the light-emitting layer in sequence; and a cathode 180 formed on the on the electron transport layer.

2 is a schematic cross-sectional view of another embodiment of the organic light-emitting element of the present invention. The organic light-emitting element 200 further includes a hole blocking layer 155 formed on the light-emitting layer 150 so that the hole blocking layer 155 is located on the electron between the transport layer 160 and the light emitting layer 150 .

3 is a schematic cross-sectional view of another embodiment of the organic light-emitting element of the present invention. In the organic light-emitting element 300, the hole assisting layer has a three-layer structure, which are formed on the anode in sequence as the first hole assisting layer 130, The second hole assisting layer 140 and the third hole assisting layer 145, wherein at least one of the first hole assisting layer 130, the second hole assisting layer 140 and the third hole assisting layer 145 contains the formula (I ) of the spirobifluorene ring compound, and the first hole auxiliary layer 130 has a P-type doping compound or a compound of formula (II).

The organic light-emitting element of the structure shown in the above drawings can be manufactured in reverse, and in the reverse structure, one or more layers may be added or removed as needed.

In a specific embodiment, the organic light-emitting device has a structure as shown in FIG. 3 , wherein the first hole auxiliary layer and the second hole auxiliary layer have the spirobifluorene compound of the formula (I), And the thicknesses of the first hole auxiliary layer, the second hole auxiliary layer and the third hole auxiliary layer are respectively 50 to 200 nanometers, 1000 to 2000 nanometers and 50 to 300 nanometers.

1000至

及50至

In another specific embodiment, the organic light-emitting device has a structure as shown in FIG. 3 , wherein the first hole auxiliary layer has a P-type doping compound or a compound of formula (II), and a third hole The auxiliary layer has the spirobifluorene ring compound of the formula (I), and the thicknesses of the first hole auxiliary layer, the second hole auxiliary layer and the third hole auxiliary layer are respectively in the range of 50 to

1000 to

and 50 to

In a specific embodiment, G ₁ and G ₂ of the aforementioned spirobifluorene ring compound of formula (I) are structures of formula (I-1), and B is selected from formulas (I-1a) and (I-1b) Structure:

Wherein, L is selected from one of the groups consisting of C, O and S;

R independently represents hydrogen, phenyl, and C _1-4 alkyl;

Ar represents a substituted or unsubstituted phenylene group, and the structure of formula (I-1a) is linked to the compound of formula (I) through Ar;

* denotes the position at which the compound of formula (I-1b) is attached to the compound of formula (I);

n represents an integer from 0 to 2;

When L is C, R represents hydrogen, phenyl, C _1-4 alkyl;

When L is O or S, n represents 0; and

m represents an integer of 0 or 1.

In another specific embodiment, G ₁ and G ₂ of the aforementioned spirobifluorene ring compound of formula (I) have the same structure.

In another specific embodiment, preferred examples of the aforementioned spirobifluorene compound of formula (I) are selected from Table 1, but are not limited thereto.

Table 1

In another specific embodiment, the above-mentioned spirobifluorene compound of formula (I) is selected from one of the following compounds:

Herein, "substituted" in the expression "substituted or unsubstituted" means that a hydrogen atom in a certain functional group is replaced by another atom or group (ie, a substituent). The substituents are each independently selected from at least one selected from the group consisting of deuterium, halogen, C _1-30 alkyl, C _1-30 alkoxy, C _6-30 aryl, C _5-30 heteroaryl base, C _5-30 heteroaryl substituted with C _6-30 aryl, benzimidazolyl, C _3-30 cycloalkyl, C _5-7 heterocycloalkyl, tri-C _1-30 alkylsilyl , tri-C _1-30 arylsilyl, di-C _1-30 alkyl C _6-30 arylsilyl, C _1-30 alkyl di-C _6-30 arylsilyl, C _2-30 alkenyl, C _2-30 alkynyl, cyano, di-C _1-30 alkylamine, di-C _6-30 arylboron, di-C _{1-30 alkylboron} , C _1-30 alkyl, C _{6- 30} aryl C _1-30 alkyl, C _1-30 alkyl C _6-30 aryl, carboxyl, nitro and hydroxyl.

In a specific embodiment, the organic light-emitting device has a structure as shown in FIG. 3 , wherein the first hole assisting layer has a P-type doping compound, and the second hole assisting layer comprises formula (III) ) compound, the third hole auxiliary layer comprises the spirobifluorene ring compound of formula (I);

A1 _- A2(III)

wherein, A ₁ and A ₂ are represented by the structure of formula (III-1) and A ₁ and A ₂ are the same or different:

wherein, R ₁ and R ₂ are the same or different, and each R ₁ and R ₂ independently represent hydrogen, C _1-4 alkyl substituted phenyl or unsubstituted phenyl;

R ₃ represents hydrogen, C _1-4 alkyl, C _1-4 alkoxy or chlorine; and

* represents the position where formula (III-1) is linked to formula (III).

In another specific embodiment, the organic light-emitting device has a structure as shown in FIG. 3 , wherein the first hole assisting layer has a P-type doping compound, and the second hole assisting layer comprises the formula ( The compound of III), the third hole auxiliary layer comprises the spirobifluorene ring compound of formula (I), and the compound of formula (III) is represented by the structure of formula (III-2);

wherein R ₁ and R ₂ are the same or different, and R ₁ and R ₂ each independently represent hydrogen, C _1-4 alkyl substituted phenyl or unsubstituted phenyl; and

R ₃ represents hydrogen, C _1-4 alkyl, C _1-4 alkoxy or chlorine.

1000至

及50至

The first hole auxiliary layer of the compound with P-type doping compound, the second hole auxiliary layer of the compound of formula (III-2) and the third hole auxiliary layer of the spirobifluorene compound of formula (I) The thicknesses range from 50 to

1000 to

and 50 to

In a specific embodiment, the light-emitting layer of the organic light-emitting element contains a fluorescent material, which is a light-emitting element that emits fluorescence. In another specific embodiment, the light-emitting layer includes a guest light-emitting body and a host light-emitting body, wherein the guest light-emitting body is especially selected from compounds having the following formula (IV), and the host light-emitting body is selected from carbazole-containing compounds The compound of the group is preferably:

By providing a hole assisting layer with at least two layers, wherein at least one layer of the hole assisting layer of the at least two layers contains the spirobifluorene compound of formula (I), and the first void formed on the anode The technical means that the hole auxiliary layer has a P-type doping compound or a compound of formula (II) can significantly reduce the driving voltage of the organic light-emitting element and improve its current efficiency, external quantum efficiency, and luminous efficiency. The organic light-emitting element material of the present invention has good heat resistance and can be applied to vehicle displays, wherein the fluorescent light-emitting element is preferably a fluorescent organic light-emitting element that emits blue light.

In another specific embodiment, the light-emitting layer of the organic light-emitting element contains a phosphorescent material, which is a phosphorescent light-emitting element. In another specific embodiment, the light-emitting layer includes a guest light-emitting body and a host light-emitting body, wherein the guest light-emitting body is especially an iridium metal complex, and the host light-emitting body is preferably selected from compounds with a carbazole group . Using the aforementioned technical means of the present invention to set up the hole auxiliary layer can also significantly improve the performance of the element with luminous efficiency and prolong the service life. components are better.

Other materials used in the hole auxiliary layer of the present invention can also be selected from conventional materials. Commonly used materials for the hole auxiliary layer include triazole derivatives, oxadiazole derivatives, imidazole derivatives, and phenylenediamine derivatives. , at least one of the group consisting of star-shaped polyamine derivatives, spirocyclic molecular derivatives or aromatic amine derivatives.

The materials used in the electron auxiliary layer of the present invention can be selected from conventional materials. Commonly used materials for the electron injection layer include alkali metal halides or alkali metal chelates containing nitrogen and oxygen, such as: LiF, 8-quinolinolato lithium ( Liq); known materials for the electron transport layer include selected from organic alkali metal/alkaline earth metal complexes, oxides, halides, carbonates and alkali metal/alkaline earth phosphates containing at least one metal selected from lithium and cesium One of the group consisting of metal salts.

The anode is a metal or conductive compound with high work function, and commonly used materials can be selected including transparent metal oxides such as: ITO, IZO, SnO ₂ , ZnO and other materials or substrates such as poly-Si, a-Si, etc. US5844363 discloses a flexible transparent substrate incorporating an anode, the entire content of which is incorporated herein by reference.

The cathode is a metal or conductive compound with low work function, and common materials can be selected including Au, Al, In, Mg, Ca or similar metals, alloys, etc. The entire content of the cathodes exemplified in US5703436 and US5707745 is the present invention As cited, the cathode has a thin metal layer, eg, magnesium/silver (Mg:Ag), and a transparent conductive layer (ITO Layer) overlying the thin metal layer by sputter deposition.

In addition, at least one of the above-mentioned electrodes needs to be transparent or semi-transparent, so as to facilitate the penetration of the emitted light.

Structures and materials not specifically described can also be applied to the present invention, such as organic light-emitting devices including polymer materials (PLEDs) disclosed in US5247190, the entire contents of which are incorporated herein by reference. As exemplified in US20030230980, the n-type doped electron transport layer is doped with lithium in BPhen at a molar ratio of 1:1, the entire content of which is incorporated herein by reference. The application and principle of each barrier layer disclosed in US6097147 and US20030230980 are incorporated herein by reference. The injection layer exemplified in US20040174116 and the protective layer described in the same case are all cited in the present invention.

Unless specifically limited, any of the layers in the various embodiments may be deposited using any suitable method. For the organic layer, preferred methods include thermal evaporation and spray printing as disclosed in US6013982 and 6087196, the entire contents of which are incorporated herein by reference; organic vapor phase deposition (OVPD) disclosed in US6337102 , the entire contents of which are cited in the present invention; the organic vapor jet printing (depositionby organic vapor jet printing, OVJP) disclosed in US10/233470, the entire contents of which are cited in the present invention. Other suitable methods include spin coating and solution based processes. Solution-based processes are preferably carried out in a nitrogen or inert gas environment. For other layers, preferred methods include thermal evaporation. Preferred patterning methods include processes of mask deposition followed by cold soldering as disclosed in US6294398 and US6468819, and integrated jet printing or organic vapor jet deposition and patterning processes, the entire contents of which are incorporated herein by reference. Of course other methods can also be used. The material used for deposition can be tailored to its particular deposition method.

The organic light-emitting element of the present invention can be applied to a single element, and its structure is an element in an array configuration or an element with cathode and anode electrodes in the X-Y coordinates of the array. Compared with the known element, the present invention can significantly improve the service life and driving stability of the organic light-emitting element.

The various properties and effects of the present invention are described in detail below by means of examples. These detailed embodiments are only used to illustrate the nature of the invention, and the invention is not limited to those exemplified by the specific embodiments.

Example 1: Manufacture of an organic light-emitting element

Before the substrate is loaded into the evaporation system for use, the substrate is cleaned with solvent and ultraviolet ozone for degreasing. Afterwards, the substrate is transferred to a vacuum deposition chamber where all layers are deposited on top of the substrate. The layers shown in Figure 3 were sequentially deposited from a heated evaporation boat at a vacuum of about ^10-6 Torr:

a) Indium tin oxide (ITO) layer, thickness

包含掺杂有2％体积比P型掺杂化合物的化合物1-2；b) First hole assisting layer, thickness

Comprising compound 1-2 doped with 2% by volume P-type doping compound;

化合物1-2；c) Second hole assisting layer, thickness

compound 1-2;

HT2；d) Third hole assisting layer, thickness

HT2;

包含掺杂有4％体积比客发光体BD的主发光体EB(BD及EB为台湾昱镭光电科技股份有限公司的商品名)；e) Light-emitting layer, thickness

Main luminophore EB (BD and EB are the trade names of Taiwan Yulei Optoelectronics Technology Co., Ltd.) doped with 4% volume ratio guest luminophore BD;

包含掺杂有5％体积喹啉锂(Liq)的化合物ET；f) Electron transport layer, thickness

Comprising compound ET doped with 5% by volume lithium quinolate (Liq);

氟化锂(LiF)；及g) Electron injection layer, thickness

lithium fluoride (LiF); and

包含A1。h) Cathode, thickness approx.

Contains A1.

The element structure can be represented as: ITO (1350 angstroms)/compound 1-2: P-type doping compound (200 angstroms)/compound 1-2 (1700 angstroms)/HT2 (100 angstroms)/EB:BD (250 angstroms)/ ET: Liq (250 Angstroms)/LiF (5 Angstroms)/Al (1500 Angstroms).

为P型掺杂化合物

P-type doped compound

Source: P-type doping compounds are provided by agents, HT2, BD, EB and ET materials are prepared by Yu Lei Optoelectronics.

After deposition of the above-mentioned layers, the device was transported from the deposition chamber to a drying oven, and then encapsulated with UV-curable epoxy resin and a glass cover plate containing a moisture absorbent. The organic light-emitting element emits blue light and has a light-emitting area of 9 square millimeters.

Examples 2 to 3: Manufacture of Organic Light Emitting Elements

Example 2 and Example 3 are the same as those of Example 1, except that Compounds 1-2 in the first hole assisting layer and the second hole assisting layer in Example 1 are replaced by Compounds 1-5 and 1-6, respectively. layer structure.

Comparative Example 1: Manufacture of an organic light-emitting element

The organic light-emitting element is arranged to have a layer structure similar to that of Example 1, except that the compounds 1-2 of the first hole assisting layer and the second hole assisting layer in Example 1 are replaced by compound HTM, the structure of the organic light-emitting element can be Expressed as: ITO (1350 angstroms)/compound HTM: P-type doped compound (200 angstroms)/compound HTM (1700 angstroms)/HT2 (100 angstroms)/EB:BD (250 angstroms)/ET:Liq (250 angstroms) /LiF (5 Angstroms)/Al (1500 Angstroms).

Source: HTM purchased by MERCK.

The electroluminescence properties of the organic light-emitting elements made above all use a constant current source (KEITHLEY2400 Source Meter, made by Keithley Instruments, Inc., Cleveland, Ohio) and a photometer (PHOTO RESEARCH SpectraScan PR 650, made by Photo Research, Inc. , Chatsworth, Calif.) measured its luminescence properties at room temperature, and the values of its driving voltage (V _d ), current efficiency, luminous efficiency, external quantum efficiency and LT97 are listed in Table 2. Among them, the LT97 value is defined as the time it takes for the brightness level to drop to a level of 97% relative to the initial brightness, as a measure for evaluating the service life or stability of the organic light-emitting element.

Table 2

Examples 4 to 5: Manufacture of Organic Light Emitting Elements

Except that the EB:BD of the light-emitting layer in Example 3 was replaced by EPH doped with 3% PEG by volume and EPH doped with 2% PER by volume, respectively, Example 4 and Example 5.

Among them, the main luminophore EPH and the guest luminophores PEG and PER of the 3% iridium metal complex doped therein are all trade names of Taiwan Yulei Optoelectronics Technology Co., Ltd.

The structure of the organic light-emitting element in Example 4 can be represented as: ITO (1350 angstroms)/compound 1-6:P-type doping compound (200 angstroms)/compound 1-6 (1200 angstroms)/HT2 (100 angstroms)/EPH : PEG (300 Å)/ET: Liq (250 Å)/LiF (5 Å)/Al (1500 Å). The organic light-emitting element of this Example 4 emits green light.

The structure of the organic light-emitting element in Example 5 can be represented as: ITO (1350 angstroms)/compound 1-6:P-type doping compound (200 angstroms)/compound 1-6 (1400 angstroms)/HT2 (100 angstroms)/EPH : PER (300 Å)/ET: Liq (300 Å))/LiF (5 Å)/Al (1500 Å). The organic light-emitting element of this Example 5 emits red light.

Comparative Examples 2 to 3: Manufacture of Organic Light Emitting Elements

The organic light-emitting element is arranged to have a structure similar to that of Example 4 and Example 5, except that the compounds 1-6 of the first hole assisting layer and the second hole assisting layer in Examples 4 and 5 are replaced by compounds HTM.

The structure of the organic light-emitting element of the comparative example 2 can be represented as: ITO (1350 angstroms)/compound HTM:P-type doping compound (200 angstroms)/compound HTM (1200 angstroms)/HT2 (100 angstroms)/EPH:PEG ( 300 Angstroms)/ET: Liq(250 Angstroms)/LiF(5 Angstroms)/Al(1500 Angstroms).

The structure of the organic light-emitting element of the comparative example 3 can be represented as: ITO (1350 angstroms)/compound HTM:P-type doping compound (200 angstroms)/compound HTM (1400 angstroms)/HT2 (100 angstroms)/EPH:PER ( 300 Angstroms)/ET: Liq(300 Angstroms)/LiF(5 Angstroms)/Al(1500 Angstroms).

The electroluminescence properties of the organic light-emitting elements prepared above were measured using the measurement method in Example 1 to evaluate the service life or stability criteria of the organic light-emitting element, and the results are shown in Table 3.

table 3

As described in Table 3, through at least two hole assisting layers, wherein at least one of the at least two hole assisting layers contains the spirobifluorene compound of formula (I), and is formed on the anode. The first hole auxiliary layer has a P-type doping compound. It can be seen that the organic light-emitting elements emitting red light and green light of the present invention have the characteristics of long service life, especially the organic light-emitting elements emitting red light are better.

Example 6: Manufacture of an organic light-emitting element

As in the manufacturing method of Example 1, the layers of materials are sequentially deposited:

a) Indium tin oxide (ITO) layer, thickness

包含掺杂有9％体积比P型掺杂化合物的HTM；b) First hole assisting layer, thickness

Contains HTM doped with 9% by volume P-type doping compound;

HTM；c) Second hole assisting layer, thickness

HTM;

化合物1-6；d) Third hole assisting layer, thickness

Compounds 1-6;

包含掺杂有4％体积比BD的EB；e) Light-emitting layer, thickness

Contains EB doped with 4% by volume BD;

ET；f) Electron transport layer, thickness

ET;

氟化锂(LiF)；及g) Electron injection layer, thickness

lithium fluoride (LiF); and

包含A1。h) Cathode, thickness approx.

Contains A1.

The element structure can be represented as: ITO (1100 angstroms)/HTM:P-type doped compound (200 angstroms)/HTM (1700 angstroms)/compounds 1-6 (100 angstroms)/EB:BD (250 angstroms)/ET (250 angstroms) Angstrom)/LiF (5 Angstroms)/Al (1800 Angstroms).

The organic light-emitting element of this Example 6 emits blue light.

Comparative Example 4: Manufacture of an organic light-emitting element

The organic light-emitting element is arranged into a layer structure similar to that of Example 6, except that the compounds 1-6 of the third hole assisting layer in Example 6 are replaced by compound HT2. The structure of the organic light-emitting element can be represented as: ITO (1100 angstroms) )/HTM: P-type doping compound (200 Å)/HTM (1700 Å)/HT2 (100 Å)/EB:BD (250 Å)/ET (250 Å)/LiF (5 Å)/Al (1800 Å) ).

The electroluminescence properties of the organic light-emitting elements prepared above were measured using the measurement method in Example 1 to evaluate the service life or stability criteria of the organic light-emitting element, and the results are shown in Table 4.

Table 4

As described in Table 4, through at least two hole assisting layers, wherein at least one layer of the at least two hole assisting layers contains the spirobifluorene compound of formula (I) and is formed on the anode The first hole auxiliary layer of the present invention has a P-type doping compound, and it can be seen that the organic light-emitting element comprising the present invention exhibits element properties such as low driving voltage and high light-emitting efficiency.

Example 7: Manufacture of an organic light-emitting element

As in the manufacturing method of Example 1, the layers of materials are sequentially deposited:

a) Indium tin oxide (ITO) layer, thickness

化合物(II)；b) First hole assisting layer, thickness

compound (II);

HT1；c) Second hole assisting layer, thickness

HT1;

化合物1-6；d) Third hole assisting layer, thickness

Compounds 1-6;

包含掺杂有4％体积比PER的EPH；e) Light-emitting layer, thickness

Contains EPH doped with 4% by volume PER;

ET；f) Electron transport layer, thickness

ET;

氟化锂(LiF)；及g) Electron injection layer, thickness

lithium fluoride (LiF); and

包含A1。h) Cathode, thickness approx.

Contains A1.

The element structure can be represented as: ITO (1100 angstroms)/compound (II) (200 angstroms)/HT1 (1400 angstroms)/compounds 1-6 (100 angstroms)/EPH:PER (300 angstroms)/ET (300 angstroms)/ LiF (5 Angstroms)/Al (1800 Angstroms).

Source: HT1 is produced by Yulei Optoelectronics.

The organic light-emitting element of this Example 7 emits red light.

Comparative Example 5: Manufacture of an organic light-emitting element

The organic light-emitting element is arranged into a layer structure similar to that of Example 7, except that the compounds 1-6 of the third hole assisting layer in Example 7 are replaced by compound HT6. The structure of the organic light-emitting element can be represented as: ITO (1100 angstroms) )/Compound (II) (200 Å)/HT1 (1400 Å)/HT6 (100 Å)/EPH:PER (300 Å)/ET (300 Å)/LiF (5 Å)/Al (1800 Å).

Source: HT6 is prepared by Yulei Optoelectronics

The electroluminescence properties of the organic light-emitting elements prepared above were measured using the measurement method in Example 1 to evaluate the service life or stability criteria of the organic light-emitting element, and the results are shown in Table 5.

table 5

As described in Table 5, through at least two hole assisting layers, wherein at least one layer of the at least two hole assisting layers contains the spirobifluorene compound of formula (I), and is formed on the anode. The compound of formula (II) in the first hole assisting layer shows that the organic light-emitting device comprising the present invention has a low driving voltage and a prolonged service life, and exhibits highly stable device performance.

The above-mentioned embodiments are only illustrative, and are not intended to limit the present invention. Any person skilled in the art can modify and change the above embodiments without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention is defined by the appended claims of the present invention, and shall be included in the technical content disclosed herein as long as the effect and implementation purpose of the present invention are not affected.

Claims (7)

1. An organic light-emitting element using a spirobifluorene ring compound, characterized by comprising:

an anode;

at least two hole assist layers sequentially formed on the anode, wherein at least one of the hole assist layers of the at least two layers contains a spirobifluorene ring compound of formula (I), and the hole assist layer formed in contact with the anode has a P-type dopant compound or a compound of formula (II);

a light-emitting layer formed on the at least two hole-assist layers;

at least one electron auxiliary layer formed on the light-emitting layer; and

a cathode formed on the electron assist layer,

in the formula, G₁And G₂Are identical or different, and G₁And G₂Each independently represents a structure of formula (I-1) or formula (I-2):

wherein B and R are the same or different, and B represents C_6-30Aryl radical, C_5-30Heterocyclic group, C_6-30Condensed polycyclic aromatic hydrocarbon radicals or C containing O, S or N hetero atoms_5-30A condensed polycyclic aromatic hydrocarbon group, and R represents C_6-30Arylene radical, C_5-30Heterocyclylene radical, divalent C_6-30Fused polycyclic aromatic hydrocarbon radicals or divalent C radicals containing O, S or N heteroatoms_5-30A condensed polycyclic aromatic hydrocarbon group;

the spirobifluorene ring compound of the formula (I) is one or two of the following compounds:

compound 1-2

Compounds 1 to 6

2. The organic light-emitting element according to claim 1, wherein the organic light-emitting element comprises three hole-assist layers, in order, a first hole-assist layer, a second hole-assist layer and a third hole-assist layer in contact with the light-emitting layer, which are formed over the anode.

3. The organic light-emitting element according to claim 2, wherein the first and second hole-assist layers comprise the spirobifluorene ring compound of formula (I).

4. The organic light-emitting element according to claim 1, wherein the light-emitting layer contains a fluorescent material.

5. The organic light-emitting element according to claim 4, wherein the light-emitting layer emits blue light.

6. The organic light-emitting element according to claim 1, wherein the light-emitting layer contains a phosphorescent material.

7. The organic light-emitting element according to claim 6, wherein the light-emitting layer emits red light or green light.

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