CN114497394B

CN114497394B - An organic electroluminescent device

Info

Publication number: CN114497394B
Application number: CN202011147601.7A
Authority: CN
Inventors: 张小庆; 叶中华; 李崇; 张兆超
Original assignee: Jiangsu Sunera Technology Co Ltd
Current assignee: Jiangsu Sunera Technology Co Ltd
Priority date: 2020-10-23
Filing date: 2020-10-23
Publication date: 2025-02-11
Anticipated expiration: 2040-10-23
Also published as: CN114497394A

Abstract

The invention discloses an organic electroluminescent device, which is provided with a substrate, a first electrode, an organic layer and a second electrode in sequence from bottom to top, wherein the organic layer comprises: a hole transport region, a light-emitting layer and an electron transport region, wherein the electron transport region comprises a first electron transport layer comprising a first electron transport compound and a second electron transport layer comprising a second electron transport compound, wherein the LUMO energy level of the first electron transport compound is between 3.2-3.5 eV, the LUMO energy level of the second electron transport compound is between 2.5-2.8 eV, and [LUMO (first electron transport compound) + LUMO (second electron transport compound)]/2 is between 2.85-3.15 eV.

Description

Organic electroluminescent device

Technical Field

The invention relates to the technical field of photoelectric devices, in particular to an organic electroluminescent device, especially an organic electroluminescent device comprising a specific electron transport layer, a preparation method thereof and a display device comprising the same.

Background

In recent years, organic electroluminescent devices have been attracting attention as full-color flat panel displays of the next generation, and have been actively studied. In order to promote the practical use and industrialization of OLEDs, a reduction in device driving voltage and a long lifetime are indispensable elements, and new electron transport layer materials have been developed to achieve these elements. In particular, a low voltage and long lifetime of the blue device must be achieved. In patent document CN102414179B, CN106661024A, CN107431141A, CN108352449a and the like, it is disclosed that triazine, pyridine, pyrimidine, imidazole, oxadiazole, triazole, phenanthroline, anthracene and other derivatives are used as electron transport layer materials, and have relatively excellent electron transport speed. They are also currently the most basic materials used for electron transport layer materials. However, in practice, there are still limitations to using such materials to reduce the voltage of the device and extend the lifetime of the device.

In addition, the hole blocking layer material is referred to in patent CN107108504a, etc. and has the feature of significantly improving the lifetime of the device, but this phenomenon is unpredictable in reducing the device voltage.

Disclosure of Invention

In order to achieve a certain balance between reducing the voltage of the device and prolonging the service life of the device, the invention provides a material collocation as an electron injection transmission layer of the device.

Furthermore, the present invention has an object to provide an organic electroluminescent device provided with a substrate and sequentially provided with an anode, an organic layer and a cathode, wherein the substrate can be provided on either the anode side or the cathode side, the organic layer includes a hole transport region, a light emitting layer, an electron transport region, wherein

A light emitting layer between the cathode and the anode and including a host material and a guest material;

a hole transport region between the anode and the light emitting layer;

an electron transport region between the cathode and the light emitting layer;

wherein the electron transport layer comprises a first electron transport layer and a second electron transport layer, wherein the second electron transport layer is positioned between the first electron transport layer and the light emitting layer;

The first electron transport layer comprises a first electron transport compound, wherein the LUMO level of the first electron transport compound (ETM 1) is between 3.2 and 3.5 eV;

the second electron transport layer comprises or consists of a second electron transport compound (ETM 2) having a LUMO energy level between 2.5 and 2.8 eV;

and [ LUMO (first electron transport layer) +lumo (second electron transport layer) ]/2 is between 2.85 and 3.15 eV.

Another object of the present invention is to provide a method of manufacturing an organic electroluminescent device according to the present invention.

It is a further object of the present invention to provide a display apparatus comprising the organic electroluminescent device according to the invention.

Technical effects

In the present invention, when two electron transport layers are selected and used and the two electron transport layers satisfy certain conditions, the organic electroluminescent device manufactured has unexpected technical effects. Specifically, when a specific first electron transporting compound according to the present invention is used as the first electron transporting layer and a specific second electron transporting compound according to the present invention is used as the second electron transporting layer, the energy level difference of the two compounds can adjust the amount of electrons injected into the light emitting layer and the ease of electron injection while allowing the recombination region to be located at an optimal recombination position in the light emitting layer. The method is favorable for reducing the driving voltage of the device, improving the stability of the device through a general formula and prolonging the service life of the device. For example, its LT90 (i.e., the time it takes for the luminance of an organic electroluminescent device to decay to 90% of its original luminance) is even beyond the T90 obtained when one electron transport compound alone is used as the electron transport layer, whereas when other types of energy level matching are employed, there is only an increase in lifetime and no improvement or even increase in voltage.

Drawings

Fig. 1 is a graph showing energy levels of a first electron transport compound (ETM 1) and a second electron transport compound (ETM 2), wherein EM represents a light emitting layer, and the graph shows energy level relationship and corresponding positions of the first transport layer and the second transport layer in the present invention.

Fig. 2 is a schematic cross-sectional view of an organic electroluminescent device according to the present invention, wherein the organic electroluminescent device comprises a substrate layer 100, and a first electrode layer anode layer 200, an organic light-emitting functional layer 300, a second electrode layer cathode layer 400 and a cover layer 500 sequentially formed on the substrate layer 100

Fig. 3 is a schematic cross-sectional view of an organic light-emitting functional layer in an organic electroluminescent device according to the present invention. Wherein the organic light emitting functional layer 300 may include an emitting layer 340 (EML), and a hole transporting region may be formed between the EML and the first electrode layer 200, and an electron transporting region may be formed between the EML and the second electrode layer 400. The hole transport region may include at least one of a hole injection layer 310 (HIL), a hole transport layer 320 (HTL), and an electron blocking layer 330 (EBL). The electron transport region may include at least one of a hole blocking layer (i.e., a second electron transport layer) 350 (ETM 2), a first electron transport layer 360 (ETM 1), and an electron injection layer 370 (EIL). Accordingly, the organic light emitting functional layer 300 includes at least 2 combinations of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

Fig. 4-5 are schematic diagrams of different luminescent material combinations of luminescent layers, wherein EM1 is a red luminescent layer, EM2 is a green luminescent layer, and EM3 is a blue luminescent layer.

FIGS. 6-7 are schematic diagrams showing structural connection of light-emitting layers including two or more organic light-emitting functional layers

The layers in the present invention will be described in more detail below.

Detailed Description

Hereinafter, embodiments of the present invention are described in detail. However, these embodiments are illustrative, the invention is not limited thereto and the invention is defined by the specification of the claims.

In the present invention, unless otherwise indicated, all operations are carried out at room temperature under normal pressure.

Herein, the term "alkyl group of C ₁-C₂₀" means a straight-chain or branched alkyl group having 1 to 20 carbon atoms, and examples thereof are methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl, sec-butyl, pentyl, isopentyl, octyl, heptyl, etc., but are not limited thereto. "C ₁-C₂₀ alkylene" refers to straight or branched chain alkylene groups having 1 to 20 carbon atoms, examples of which include, but are not limited to, divalent groups of the above groups.

As used herein, the term "aryl group of C ₅-C₆₀" refers to a monovalent radical of a fully unsaturated monocyclic, polycyclic or fused polycyclic (i.e., rings sharing a pair of adjacent carbon atoms) system having 5 to 30 ring carbon atoms, examples of which include, but are not limited to, phenyl, naphthyl, anthryl, phenanthryl, fused tetraphenyl, pyrenyl, biphenyl, p-biphenyl, m-biphenyl, anthryl, p-biphenyl,A group, a biphenylene group, a perylene group, an indenyl group, a triphenylene group, a fluorenyl group, a dimethylfluorenyl group, a diphenylfluorenyl group,Etc. "C ₅-C₃₀ arylene" is a divalent radical of a fully unsaturated monocyclic, polycyclic, or fused polycyclic (i.e., rings sharing a pair of adjacent carbon atoms) system having 5 to 30 ring carbon atoms, examples of which include, but are not limited to, divalent radicals of the foregoing radicals.

Herein, the term "C ₂-C₆₀ heteroaryl" refers to an aromatic monovalent group having 2 to 59 ring carbon atoms and at least one heteroatom selected from N, O and S, examples of which include, but are not limited to, furyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, oxazolyl, thiazolyl, oxadiazolyl, thiadiazolyl, pyridyl, pyrimidinyl, pyrazinyl, triazinyl, benzofuranyl, benzothienyl, benzimidazolyl, indolyl, quinolinyl, isoquinolinyl, quinazolinyl, quinolyl, naphthyridinyl, benzoxazolyl, benzothiazinyl, acridinyl, keazinyl, kethiazinyl, keoxazinyl, dibenzofuranyl, dibenzothienyl, carbazolyl, and the like, as well as aromatic combination groups with heteroatoms, for example Etc. "C ₂-C₆₀ heteroarylene" refers to an aromatic divalent group having 2 to 59 ring carbon atoms and at least one heteroatom selected from N, O and S, examples of which include, but are not limited to, divalent groups of the foregoing groups.

It will be understood that the terms "comprises" and/or "comprising," when used herein, specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components.

As used herein, the term "organic functional material layer" refers to a single layer and/or multiple layers located between a first electrode and a second electrode in an organic electroluminescent device. The material included in the organic functional material layer is not limited to an organic material.

The prefix "substituted or unsubstituted" as used herein before a group means that the group is optionally substituted with at least one group selected from cyano, halogen, C _1-20 alkyl, C _2-20 alkenyl, C _6-30 aryl, C _2-30 heteroaryl, or unsubstituted. The hetero atom in the heteroaryl group and the heteroarylene group is optionally selected from at least one of an oxygen atom, a sulfur atom, or a nitrogen atom, and examples of the substituent include, but are not limited to, phenyl, biphenyl, anthracenyl, naphthyl, pyridyl, triazolyl, methyl, dimethylfluorenyl, fluorenyl, diphenylfluorenyl, N-phenylbenzimidazolyl, N-phenylcarbazolyl, spirobifluorenyl, dibenzofuran, benzimidazolyl, and the like.

Any numerical range recited herein is intended to include all sub-ranges subsumed therein with the same numerical accuracy. For example, "1.0 to 10.0" means all subranges included between the minimum value of 1.0 listed and the maximum value of 10.0 listed (and including 1.0 and 10.0), that is, all subranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0. Any maximum numerical limitation listed herein is meant to include all smaller numerical limitations, and any minimum numerical limitation listed herein is meant to include all larger numerical limitations, all smaller numerical limitations, and all smaller numerical limitations, all larger numerical limitations, and all smaller numerical limitations, all as recited herein are meant to be included herein. Accordingly, the applicant reserves the right to modify the claims and specification to expressly describe any subrange that falls within the range explicitly described herein.

Hereinafter, the organic electroluminescent device of the present invention will be described according to specific embodiments. It is noted that the specific embodiments do not limit the invention.

In one embodiment of the present invention, there is provided an organic electroluminescent device, wherein,

The first electron transport compound may include one or more of compounds having a structure represented by general formula (1-1) -general formula (1-3)

The second electron transport compound may include, or consist of one or more of compounds having the structures represented by the general formula (2-1) and the general formula (2-2),

In the general formula (I), the amino acid is as shown in the specification,

X ₁-X₉ may each independently represent a C-R or N atom;

Z ₁-Z₈ may be independently represented as a C-R or N atom;

Y may represent a single bond, -O-, -S-, -CR ₁₀R₁₁ -, or-N-R ₁₂;

L ₁-L₄ is independently represented by a single bond, alkylene of C ₁-C₂₀, arylene of substituted or unsubstituted C ₅-C₆₀, or heteroarylene of substituted or unsubstituted C ₂-C₆₀, preferably phenylene, biphenylene, terphenyl;

Ar ₁-Ar₈ may be independently represented as a substituted or unsubstituted aryl group of C ₅-C₆₀ or a substituted or unsubstituted heteroaryl group of C ₂-C₆₀, preferably phenyl, naphthyl, biphenyl, terphenyl, anthracenyl, phenanthrenyl, pyridyl, pyrimidinyl, furyl, benzofuryl, dibenzofuryl, imidazolyl, benzimidazolyl, indolyl, benzoindolyl, carbazolyl, N-phenylcarbazolyl,

Cy may be represented as a substituted or unsubstituted heteroaryl group of C ₂-C₆₀, preferably pyridyl, pyrimidinyl, triazinyl, imidazolyl, benzimidazolyl, indolyl, benzindolyl, carbazolyl, N-phenylcarbazolyl, furanyl, benzofuranyl, dibenzofuranyl, quinolinyl, isoquinolinyl or

R represents a hydrogen atom, a substituted or unsubstituted phenyl group, a naphthyl group, a biphenyl group, a pyridyl group, wherein the substituted substituent can be one or more of a phenyl group, a methyl group, an ethyl group, a propyl group and a butyl group;

R ₁-R₇ can be independently represented as hydrogen, substituted or unsubstituted C ₅-C₆₀ aryl, or substituted or unsubstituted C ₂-C₆₀ heteroaryl, preferably naphthyl, anthracenyl, phenanthrenyl, pyrenyl,

R ₈-R₉ is independently represented by a substituted or unsubstituted C ₅-C₆₀ aryl group, or a structure represented by the general formula (3)

R ₁₀-R₁₂ is independently represented as C _1-20 alkyl, substituted or substituted C _5-60 aryl or substituted or unsubstituted C ₂-C₆₀ heteroaryl;

Wherein R ₁₃、R₁₄ is independently represented as a halogen atom, a substituted or unsubstituted C ₁-C₂₀ alkyl group, a substituted or unsubstituted C ₅-C₆₀ aryl group, or a substituted or unsubstituted C ₂-C₆₀ heteroaryl group, and R ₁₃ and R ₁₄ may be linked by a single bond to form a 5-7 membered ring;

r ₁₅、R₁₆ is independently selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group,

General formula (3-1) general formula (3-2) general formula (3-3) is connected with general formula (3) into a parallel ring through "+",

R ₈-R₉ is preferably

Wherein Y ₁-Y₃ is independently represented by-O-, -S-, -CR ₁₇R₁₈ -or N-R ₁₉;

The definition of R ₁₇-R₁₉ is consistent with the definition of R ₁₀-R₁₂.

In a preferred embodiment of the organic electroluminescent device according to the present invention, the first electron transport compound may comprise one or more of the following compounds:

In a preferred embodiment of the organic electroluminescent device according to the invention, the second electron transporting compound may comprise or consist of one or more of the following compounds:

In a preferred embodiment of the organic electroluminescent device according to the present invention, wherein the hole transport region comprises, in order, a hole injection layer, a hole transport layer and an electron blocking layer, wherein the hole injection layer is located between the anode and the hole transport layer, the hole transport layer is located between the hole injection layer and the electron blocking layer, and the electron blocking layer is located between the light emitting layer and the hole transport layer.

In a preferred embodiment of the organic electroluminescent device according to the invention, the electron transport region further comprises an electron injection layer, the electron injection layer being located between the first electron transport layer and the cathode layer.

In a preferred embodiment of the organic electroluminescent device according to the invention, the first electron transport layer is doped with a first electron transport compound and other compounds conventionally used for electron transport layers, preferably with a first electron transport compound and Liq (lithium 8-hydroxyquinoline).

In a preferred embodiment of the organic electroluminescent device according to the invention, the second electron-transporting layer consists of one or more compounds selected from the group of second electron-transporting compounds, preferably of one second electron-transporting compound.

In a more preferred embodiment of the organic electroluminescent device according to the invention, wherein the weight ratio of the first electron transporting compound to Liq is in the range of about 1:10 to 10:1, preferably about 1:9 to 9:1, more preferably about 2:8 to about 8:2.

Preferably, other structures in the organic electroluminescent device of the present invention are specifically described below.

Referring to fig. 2, an organic electroluminescent device of the present invention includes a substrate layer 100, an anode layer 200, an organic light emitting functional layer 300, a cathode layer 400, and a capping layer 500.

Substrate layer

The substrate may be any substrate commonly used for organic electroluminescent devices. For example, the substrate may be a glass substrate or a transparent plastic substrate having good mechanical strength, thermal stability, transparency, surface flatness, handling convenience, and water resistance, but is not limited thereto.

Anode layer

According to the organic electroluminescent device of the present invention, an anode may be provided on the substrate. Alternatively, the anode may not be provided on the substrate, but the cathode may be provided on the substrate.

In a preferred embodiment of the organic electroluminescent device of the present invention, the anode material is preferably a material having a high work function so that holes are easily injected into the organic functional material layer. Non-limiting examples of the first electrode material include, but are not limited to, indium Tin Oxide (ITO), indium Zinc Oxide (IZO), tin oxide (SnO ₂), zinc oxide (ZnO), magnesium (Mg), aluminum (Al), silver (Ag), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag). The first electrode 2 may have a single-layer structure or a multi-layer structure including two or more layers. For example, the first electrode 2 may have a three-layer structure of ITO/Ag/ITO, but is not limited thereto. In addition, the thickness of the first electrode is generally 50 to 500nm, preferably 70 to 300nm and more preferably 100 to 200nm, depending on the material used.

Hole transport region

The organic electroluminescent device according to the present invention may be provided with a hole transport region, which may include, but is not limited to, for example, a hole injection layer 310, a hole transport layer 320, and an electron blocking layer 330 in this order. The hole transport region may have a single layer structure formed of a single material, a single layer structure formed of a plurality of different materials, or a multilayer structure having a plurality of layers formed of a plurality of different materials.

When the hole transport region includes a hole transport layer, the material of the hole transport layer is preferably a material having high hole mobility, which enables holes to be transferred from the anode or the hole injection layer to the light emitting layer. The hole transport material may include the following compounds HT1 to HT25, but is not limited thereto:

According to the present invention, HT23 is preferably used as the hole transport layer material. The thickness of the hole transport layer of the present invention may be 5 to 200nm, preferably 10 to 180nm and more preferably 20 to 150nm.

In addition to the above materials, the hole injection layer and/or the hole transport layer may further include a charge generation material to improve conductive properties. The charge generating material may be uniformly or non-uniformly dispersed in the hole injection layer and/or the hole transport layer. The charge generating material may be, for example, a P-dopant. The P-type doped material is mainly used for hole injection, and the P-type doped material is doped into the hole transport body to form a charge transfer state with the hole transport body material, so that holes are injected into the organic material layer more easily. In a preferred embodiment of the invention, the P-type doping material used is selected from one of the following organic compounds:

The hole transport region may include a buffer layer, an electron blocking layer, or a combination thereof in addition to the hole injection layer and the hole transport layer. The buffer layer may compensate for an optical resonance distance according to a wavelength of light emitted from the light emitting layer, and thus may improve light emitting efficiency of the organic electroluminescent device. The electron blocking layer may prevent electrons from being injected from the electron transport region. In specific embodiments, the electron blocking layer compound may be selected from the following compounds EB1 to EB7, but is not limited thereto:

The thickness of the electron blocking layer of the present invention may be 1 to 200nm, preferably 5 to 150nm and more preferably 10 to 100nm.

Light-emitting layer

The organic electroluminescent device according to the present invention is provided with a light emitting layer. The material of the light emitting layer is a material capable of emitting visible light by receiving holes from the hole transporting region and electrons from the electron transporting region, respectively, and combining the received holes and electrons.

In a preferred embodiment of the present invention, the host material of the light-emitting layer used is selected from one or more combinations of the following EMH-1 to EMH-22:

In addition, the light emitting layer guest material may further include a phosphorescent or fluorescent material in order to improve fluorescence or phosphorescence characteristics. The phosphorescent material includes a phosphorescent material such as a metal complex of iridium, platinum, or the like. For example, a green phosphorescent material such as Ir (ppy) ₃ [ fac-tris (2-phenylpyridine) iridium ], a blue phosphorescent material such as FIrpic or FIr6, and a red phosphorescent material such as Btp ₂ Ir (acac) may be used. For the fluorescent material, those generally used in the art can be used. In a preferred embodiment of the present invention, the light-emitting layer guest material used is selected from one of the following EMD-1 to EMD-23:

in the light-emitting layer of the present invention, the ratio of host material to guest material used is 99:1 to 70:30, preferably 99:1 to 85:15 and more preferably 97:3 to 87:13 on a mass basis.

In addition, in order to obtain the organic electroluminescent unit with high efficiency, besides the above-mentioned fluorescent or phosphorescent host-guest materials, the light-emitting layer may further use another guest material, or use multiple guest materials, where the guest material may be a simple fluorescent material, delayed fluorescence (TADF) material, or phosphorescent material, or different fluorescent materials, TADF materials, or phosphorescent materials are combined, and the light-emitting layer may be a single light-emitting layer material, or may be a composite light-emitting layer material stacked together transversely or longitudinally. The light-emitting layer constituting the organic electroluminescent device has various configurations as follows:

(1) A single organic light emitting layer material;

(2) Any combination of blue organic light emitting layer material and green, yellow or red light emitting layer material, not in the order of the layers, as shown in fig. 4;

(3) Any two combinations of blue organic light emitting layer material and green, yellow or red light emitting layer material are not in order, as shown in fig. 5;

(4) Any one of the blue organic light emitting layer material and the green, yellow or red light emitting layer material is combined, and charge transport is performed through the connection layer, so as to form a two-layered device structure, as shown in fig. 6;

(5) Any two of the blue organic light emitting layer materials and the green, yellow or red light emitting layer materials are combined and charge transport is performed through the connection layer, forming a three-layered device structure, as shown in fig. 7.

Preferably, the organic light emitting functional layer comprises a light emitting layer comprising a combination of 1 or at least 2 of blue, green, red, yellow organic light emitting layer materials.

In fig. 6 and 7, 300 represents an organic light emitting functional layer, 610, 620 and 630 represent a connection layer, and the connection layer material combination may be any one of (1) n-type doped organic layer/inorganic metal oxide such as Bphen: li/MoO ₃、Alq3:Mg/WO₃、BCP:Li/V₂O₅ and BCP: cs/V ₂O₅, (2) n-type doped organic layer/organic layer such as Alq3: li/HAT-CN, (3) n-type doped organic layer/p-type doped organic layer such as Bphen: cs/NPB: F4-TCNQ, alq3: li/NPB: feCl ₃、TPBi:Li/NPB:FeCl₃ and Alq3: mg/m-MTDATA: F4-TCNQ, (4) undoped type such as F16CuPc/CuPc and Al/WO ₃/Au.

In order to adjust the effective combination of carrier charges in the light-emitting layer, the film thickness of the light-emitting layer 340 constituting the OLED light-emitting body may be arbitrarily adjusted as required, or light-emitting layers which cannot be colored may be alternately stacked and combined as required, and charge blocking layers for different functional purposes may be added to the organic layers adjacent to the light-emitting layers.

The thickness of the light-emitting layer of the present invention may be, for example, 5 to 60nm, preferably 10 to 50nm, more preferably 20 to 45nm.

Electron transport region

The organic electroluminescent device according to the present invention is provided with an electron transport region which is disposed between the light emitting layer and the cathode, and may include a first electron transport layer and a second electron transport layer, and an electron injection layer, wherein the first electron transport compound (ETM 1) is a material that easily receives electrons of the cathode and transfers the received electrons to the second electron transport layer, preferably, the first electron transport layer is disposed between the light emitting layer and the electron injection layer, and the second electron transport layer, also referred to as a hole blocking layer, is disposed between the first electron transport layer and the light emitting layer.

The details of the compounds of the first electron transport layer and the second electron transport layer are as described above.

The first electron-transporting compound of the present invention is preferably used as the first electron-transporting layer, alone or in combination with other materials conventionally used for electron transport, preferably in combination with Liq, with one or more of the above-mentioned specific compounds 1-1, 1-8, 1-17, 1-29, 1-38, 1-44, 1-58, 1-63, 1-64, 1-72.

The first electron transport layer of the present invention may have a thickness of 10 to 80nm, preferably 20 to 60nm, more preferably 25 to 45nm.

The second electron transport compound (ETM 2) also has a high electron transport rate.

As the second electron transport layer material of the present invention, one or more of the above specific compounds 2-1, 2-8, 2-28, 2-40, 2-43, 2-54, 2-63, 2-72, and more preferably one of them, are used alone.

The second electron transport layer (ETM 2) of the present invention may have a thickness of 5 to 60nm, preferably 5 to 30nm, more preferably 5 to 20nm.

In a preferred embodiment of the organic electroluminescent device of the present invention, the electron injection layer material is preferably a material having a low work function so that electrons are easily injected into the organic functional material layer. As the electron injection layer material of the present invention, an electron injection layer material for an organic electroluminescent device known in the art, for example, lithium salts such as lithium 8-hydroxyquinoline, lithium fluoride, lithium carbonate or lithium azide, or cesium salts, cesium fluoride, cesium carbonate or cesium azide, or ytterbium, may be used. The thickness of the electron injection layer of the present invention may be 0.1 to 5nm, preferably 0.5 to 3nm, more preferably 0.8 to 1.5nm.

Cathode electrode

The organic electroluminescent device of the present invention is provided with a cathode. The material used to form the cathode may be a material having a low work function, such as a metal, an alloy, a conductive compound, or a mixture thereof. Non-limiting examples of the second electrode may include lithium (Li), ytterbium (Yb), magnesium (Mg), aluminum (Al), calcium (Ca), and aluminum-lithium (Al-Li), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag). The thickness of the second electrode depends on the material used, and is generally 5-100nm, preferably 7-50nm and more preferably 10-25nm.

Light extraction layer (cover layer)

In order to improve the light extraction efficiency of the organic electroluminescent device, a light extraction layer, i.e., a capping layer 500 (CPL layer), may be further added over the second electrode (i.e., cathode) of the device. According to the optical absorption and refraction principles, the higher the refractive index of the CPL cover layer material is, the better the CPL cover layer material is, and the smaller the light absorption coefficient is, the better the CPL cover layer material is. Any material known in the art may be used as the CPL layer material, e.g., alq3, CP-1

The CPL coating typically has a thickness of 5-300nm, preferably 20-100nm and more preferably 40-80nm.

The organic electroluminescent device may further include an encapsulation structure. The encapsulation structure may be a protective structure that prevents foreign substances such as moisture and oxygen from entering the organic layer of the organic electroluminescent device. The encapsulation structure may be, for example, a can such as a glass can or a metal can, or a film covering the entire surface of the organic layer.

Method for preparing organic electroluminescent device

The present invention also relates to a method for preparing the above-mentioned organic electroluminescent device, comprising sequentially laminating the anode, the organic layer and the cathode according to the present invention, or sequentially laminating the cathode, the organic layer and the anode according to the present invention, on a substrate. Preferably, the organic layer is formed by sequentially laminating a hole transport region, a light emitting layer, and an electron transport region on the anode, and the hole transport region is formed by sequentially laminating a hole injection layer, a hole transport layer, and an electron blocking layer on the anode. Preferably, the electron transport region is formed by sequentially laminating a hole blocking layer, an electron transport layer, and an electron injection layer on the light emitting layer. In addition, a CPL layer can be laminated on the electrode at the light-emitting side so as to improve the light-emitting efficiency of the organic electroluminescent device.

As for lamination, methods such as vacuum deposition, vacuum evaporation, spin coating, casting, LB method, inkjet printing, laser printing, or LITI may be used, but are not limited thereto. Wherein vacuum evaporation means heating and plating a material onto a substrate in a vacuum environment.

In the present invention, the layers are preferably formed using a vacuum evaporation process, wherein the layers may be formed at a temperature of about 100-500 ℃ and at a vacuum of about 10 ^-8-10^-2 torr and a vacuum of aboutVacuum evaporation was performed at a rate of (2). Preferably, the temperature is 200-400 ℃, more preferably 250-300 ℃. The vacuum is preferably 10 ^-6-10^-2 torr, more preferably 10 ^-5-10^-3 torr. The rate is aboutMore preferably about

The material for forming each layer according to the present invention may be used as a single layer by forming a film alone, or may be used as a single layer by forming a film after mixing with another material, or may be a laminated structure between layers formed by forming a film alone, a laminated structure between layers formed by mixing, or a laminated structure between layers formed by forming a film alone and layers formed by mixing.

The invention also relates to a display device, in particular a flat panel display device, comprising an organic electroluminescent device according to the invention. In a preferred embodiment, the display apparatus may comprise one or more of the above-described organic electroluminescent devices, and in the case of comprising a plurality of devices, the devices are combined in a stacked manner, either laterally or longitudinally. Preferably, the display device includes devices each having an organic light emitting material layer of three colors of blue, green, and red, the devices each having an electron blocking layer of the same or different film thickness, and the materials of the electron blocking layers being the same or different. The display device may further include at least one thin film transistor. The thin film transistor may include a gate electrode, source and drain electrodes, a gate insulating layer, and an active layer, wherein one of the source and drain electrodes may be electrically connected to a first electrode of the organic electroluminescent device. The active layer may include crystalline silicon, amorphous silicon, an organic semiconductor, or an oxide semiconductor, but is not limited thereto.

Exemplary embodiments have been disclosed herein, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. In some cases, as will be apparent to one of ordinary skill in the art as the present disclosure proceeds, features, characteristics, and/or elements described in connection with a particular embodiment may be used alone or in combination with features, characteristics, and/or elements described in connection with other embodiments unless specifically indicated. Accordingly, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the application.

The following examples are intended to better illustrate the invention, but the scope of the invention is not limited thereto.

Examples

I. Preparation of Compounds example

Preparation of first and second electron transport compounds

(1) Synthesis of Compounds 1-1, 1-8, 1-17, 1-29, 1-38, 1-44, 1-58, 1-63, 1-64, 1-72 (ETM 1)

The synthesis of the compounds 1-1, 1-8, 1-17, 1-29, 1-38, 1-44, 1-58, 1-63, 1-64, 1-72 may be synthesized directly by reference to the methods of the patents KR2014094408A, KR2017003502A, KR2017065317, CN102471679, etc. or purchased directly commercially.

(2) Synthesis of Compounds 2-1, 2-8, 2-23, 2-28, 2-40, 2-43, 2-54, 2-63, 2-72 (ETM 2)

The synthesis of the compounds 2-1, 2-8, 2-23, 2-28, 2-40, 2-43, 2-54, 2-63, 2-72 can be directly synthesized by referring to the synthesis method in CN109748899A, EP3312895 and WO 2016105141.

Test examples of Compounds

The compounds prepared in I were tested.

For the direct measurement of the HOMO level of the OLED material, there are various means, including CV method, UPS method, IPS method, AC method, etc., and the HOMO level prediction of the OLED material may also be achieved by means of quantization calculation. Among the above measurement methods, the CV method is greatly affected by the solvent and the operation method, the measured values tend to be greatly different, when the AC method is used for measuring, the sample needs to be placed in a dry air environment, when high-energy ultraviolet monochromatic light acts on the surface of the sample, electrons escaping need to be combined with oxygen in the air, and the detector can obtain signals, so that the sample material is greatly affected by oxygen elements in the environment, and the measurement of the HOMO level of the material with some deep HOMO levels (such as P-doped material) is inaccurate.

The method can test the photoelectron spectrum of the OLED material in a high vacuum environment, so that adverse environmental influence can be removed to the greatest extent, the preparation environment atmosphere of the OLED light-emitting device is approached, and the in-situ measurement concept is approached to the greatest extent, so that compared with other measurement methods, the method has higher numerical accuracy in terms of measurement method. Even so, it is emphasized that the HOMO energy levels of different materials are tested, so that only the consistency of equipment and methods is achieved, the influence of a testing environment is avoided, and the HOMO energy levels among the materials have absolute contrast significance. All the measurement means related to the HOMO energy level of the material are IPS.

The specific measurement method is as follows:

HOMO energy level by vacuum evaporation equipment, and vacuum degree of 1.0E-5Pa, controlling evaporation rate to be Evaporating the material on an ITO substrate, wherein the film thickness is 60-80nm, and measuring the HOMO energy level of the sample film by using an IPS3 measuring device, wherein the measuring environment is a vacuum environment below 10 ^-2 Pa.

Eg energy level is calculated by drawing a tangent line based on the ascending side of the ultraviolet spectrophotometry (UV absorption) base line and the first absorption peak of the material single film and using the value of the intersection point of the tangent line and the base line.

LUMO level is calculated based on the difference between the HOMO level and Eg level.

Table 1 shows the results of the respective energy level tests of the light-emitting host materials (EMH-1, EMH-10, EMH-11 and EMH-13), the guest materials (EMD-1, EMD-8 and EMD-13), the first electron transport compounds (compounds of the general formulae (1-1) to (1_3)) and the second electron transport compounds (compounds of the general formulae (2-1) to (2-2)).

TABLE 1

As can be seen from the results of Table 1, the first electron-transporting compound of the present invention has a HOMO level of 6.2-6.75eV and a LUMO level of 3.2-3.45eV;

The second electron transporting compound has a HOMO level of 5.9-6.2eV and a LUMO level of 2.6-2.8eV.

In the production of an organic electroluminescent device using the first electron transport compound and the second electron transport compound of the present invention, it is necessary that LUMO levels of the first electron transport compound and the second electron transport compound satisfy:

The value of [ LUMO (first electron transporting compound) +LUMO (second electron transporting compound) ]/2 is in the range of 2.85-3.15eV, preferably in the range of 2.9-3.12 eV.

Unless otherwise indicated, the various materials used in the following examples and comparative examples are commercially available or may be obtained by methods known to those skilled in the art.

III device preparation examples

The compounds prepared in I were used for the first electron transport compound and the second electron transport compound, respectively, to prepare organic electroluminescent devices.

The structures of the compounds HT23, P1, CP-1, EB6, EB7, EMH-1, EMD-1, EMH-13, EMD-14, EMH-10, EMH-11, etc. used in the examples are as described above.

Vacuum evaporation was performed under the conditions that a OLED Chuster Deposition System (manufacturer: CHOSHU INDUSTRY Co. LTD.) vacuum evaporation apparatus of model 1504-10117-01_0 was used under a vacuum of 1.0X10. 10 ^-7 Torr, wherein when only one material was used to form a layer, the evaporation rate was controlled to beIf two or more materials are used in the same layer, the materials are each separately placed in one vapor deposition source and the vapor deposition rates are set so that the ratio of the vapor deposition rates is equal to the mass ratio thereof, for example, when the first and second host materials are used in the light-emitting layer and the doping materials are used, the three materials are respectively placed in the three vapor deposition sources, and when the mass ratio thereof is 50:50:6, the vapor deposition rates are controlled to be respectivelyAnd

Device example B-1 (BLUE)

A) A transparent PI film was used as the substrate layer 100, which was washed, i.e., sequentially washed with a cleaning agent (SEMICLEAN M-L20), washed with pure water, then dried, and further washed with ultraviolet-ozone to remove organic residues on the surface of the anode layer. Ag (150 nm) was evaporated on the washed substrate layer 100 as the anode layer 2.

B) HT23 and P1 are placed in two vapor deposition sources on the anode layer 200, and the vapor deposition rates are controlled to be respectivelyAndThe resulting layer was a hole injection layer 310, and the film thickness was 10nm.

C) On the hole injection layer 310, HT23 was deposited as a hole transport layer 320, and the film thickness was 130nm.

D) EB6 was deposited as an electron blocking layer 330 on the hole transport layer 320, and the film thickness was 20nm.

E) On the electron blocking layer 330, the host compound EMH-1 and the doping material EMD-1 are respectively placed into two vapor deposition sources, and the vapor deposition rates are controlled to be respectivelyThe resulting layer was used as the light-emitting layer 340, and the film thickness was 20nm.

F) On the light-emitting layer 340, the second electron-transporting layer 350 was formed of the vapor-deposited compound 2 to 8, and the film thickness was 5nm.

G) On the second electron transport layer 350, electron transport compounds 1-1 and Liq are placed in two vapor deposition sources, and the vapor deposition rates are controlled to be respectivelyAndThe resulting layer was used as the first electron transport layer 360, and the film thickness was 30nm.

H) Yb was vapor deposited as an electron injection layer 370 on the first electron transport layer 360, and the film thickness was 1nm.

I) On the electron injection layer 370, mg and Ag are put into two vapor deposition sources, and the vapor deposition rates are controlled to be respectivelyAndThe resulting layer was used as a cathode layer 400, and the film thickness was 15nm.

J) On the cathode layer 400, CP-1 was deposited as a coating layer 500, and the film thickness was 70nm.

Device example R-1 (RED)

A) A transparent PI film was used as the substrate layer 100, which was washed, i.e., sequentially washed with a cleaning agent (SEMICLEAN M-L20), washed with pure water, then dried, and further washed with ultraviolet-ozone to remove organic residues on the surface of the anode layer. Ag (150 nm) was evaporated on the washed substrate layer 100 as an anode layer 200.

B) On the anode layer 2, HT23 and P1 are put into two evaporation sources, and the evaporation rates are controlled to be respectivelyAndThe resulting layer was a hole injection layer 310, and the film thickness was 10nm.

D) EB7 was vapor deposited as an electron blocking layer 330 on the hole transport layer 320, and the film thickness was 40nm.

E) On the electron blocking layer 330, the host compound EMH-13 and the doping material EMD-14 are respectively placed into two vapor deposition sources, and the vapor deposition rates are controlled to be respectivelyThe resulting layer was used as the light-emitting layer 340, and the film thickness was 40nm.

H) Yb was vapor deposited as an electron injection layer 370 on the second electron transport layer 360, and the film thickness was 1nm.

Device example G-1 (GREEN)

D) EB6 was deposited as an electron blocking layer 330 on the hole transport layer 320, and the film thickness was 40nm.

E) On the electron blocking layer 330, the host compound EMH-10, the host compound EMH-11 and the doping material EMD-13 are respectively placed into three vapor deposition sources, and the vapor deposition rates are controlled to be respectivelyAndThe resulting layer was used as the light-emitting layer 340, and the film thickness was 40nm.

F) On the light-emitting layer 340, compound 2-1 was vapor-deposited as the second electron transport layer 350, and the film thickness was 5nm.

Examples R-2 to R-11

An organic electroluminescent device was prepared in the same manner as in device example R-1 except that the compounds shown in table 2 were used in step f) to form ETM2 of examples 2 to 16 and the compounds shown in table 2 were used in step g) to form ETM1 of examples 2 to 16, wherein the evaporation rate was controlled to be 50:50 when the ratio of ETM1 to Liq was 50AndThe specific ETM2 and ETM1 compounds used are shown in table 2.

Device comparative example R-1

An organic electroluminescent device was prepared in the same manner as in device example R-1, except that step f) was omitted, step g was performed using compound 1-1 as ETM1, wherein the ratio of compound 1-1 to Liq was 50:50, and the controller evaporation rate wasAndAnd the thickness of this layer was 35nm.

Device comparative example R-2

An organic electroluminescent device was fabricated according to the same idea as that of device example R-1, except that the compounds 2 to 23 shown in Table 2 were used in step f) to form ETM2 of device comparative example R-2, and the compound Alq3 shown in Table 2 was used in step g) to form ETM1 of device comparative example R-2, wherein the evaporation rate was controlled to be 50:50 when the ratio of Alq3 to Liq was 50AndThe specific ETM2 and ETM1 compounds used are shown in table 2.

Device examples G-2 to G-11, comparative examples G-1 and G-2

An organic electroluminescent device was prepared in the same manner as in device example G-1, except that the first electron transport layer ETM1 and the second electron transport layer ETM2 each used the compounds shown in table 3.

Device examples B-2 to B-11, and comparative examples B-1 and B-2

An organic electroluminescent device was prepared in the same manner as in device example B-1, except that the first electron transport layer ETM1 and the second electron transport layer ETM2 each used the compounds shown in table 4.

Device test examples

All devices prepared in III were tested. The test method is as follows:

The driving voltage and current efficiency were data tested at 10mA/cm ², and the voltage, current efficiency and color coordinates were tested using an IVL (Current-Voltage-Brightness) test system (French scientific instruments Co., ltd., su.).

LT95 refers to the time taken for the brightness of the device to decay to 95% of the original brightness under the condition of 10000nits, and the life test system is an EAS-62C type OLED device life tester of Japan systems research company.

The test results are shown in tables 2 to 4 below.

TABLE 2 device preparation example R-1~R-12 device comparative examples R-1 and R-2 organic electroluminescent devices prepared

TABLE 3 preparation of devices example G-1 to G-12 devices and organic electroluminescent devices prepared by comparative examples G-1 and G-2

TABLE 4 device preparation example B-1~B-12 device comparative examples B-1 and B-2 organic electroluminescent devices prepared

As can be seen from the device data results of tables 2 to 4, in the red, green, and blue light emitting devices, the inventive examples R-1 to R-12, G-1 to G-12, and B-1 to B-12 each achieved better effects, for example, lower driving voltage, longer LT95 lifetime, and higher current efficiency, compared to the device comparative examples R-1, G-1, and B-1 using the compound according to the present application as the first electron transporting compound, and the device comparative examples R-2, G-2, and B-2 using the prior art material Alq3: liq (1:1) as the first electron transporting layer, and the compound according to the present application as the first electron transporting compound. In particular, compared with the prior art, the red light-emitting device and the green light-emitting device prepared by matching the first electron transport layer and the second electron transport layer have a remarkably better technical effect. For the red light emitting device, the current efficiency of the inventive example was comparable to that of the comparative example but the driving voltage was significantly reduced and the lifetime was significantly prolonged.

From the above, it can be seen that by employing the first electron transport compound for the first electron transport layer and the second electron transport compound for the second electron transport layer according to the present application satisfying the following conditions:

The LUMO level of the first electron transporting compound (ETM 1) is between 3.2-3.5 eV;

The LUMO level of the second electron transporting compound (ETM 2) is between 2.5-2.8 eV;

And [ LUMO (first electron transporting compound) +LUMO (second electron transporting compound) ]/2 is between 2.85 and 3.15eV,

The prepared blue, green and red organic electroluminescent devices all achieve better technical effects. In particular, the electron transport layer of the present application is more suitable for red light emitting devices and green light emitting devices, especially red light emitting devices.

Claims

1. An organic electroluminescent device, which is provided with a substrate and an anode, an organic layer and a cathode in sequence, wherein the substrate is arranged on the anode side or on the cathode side, the organic layer includes a hole transport region, a light emitting layer, and an electron transport region, wherein

a light-emitting layer, located between the cathode and the anode, and comprising a host material and a guest material;

The hole transport region is located between the anode and the light-emitting layer;

The electron transport region, located between the cathode and the light-emitting layer;

Characterized in that the electron transport region includes a first electron transport layer and a second electron transport layer, wherein the second electron transport layer is located between the first electron transport layer and the light-emitting layer;

The first electron transport layer comprises a first electron transport compound, wherein the LUMO energy level of the first electron transport compound (ETM1) is between 3.2-3.5 eV;

The second electron transport layer comprises or consists of a second electron transport compound, and the LUMO energy level of the second electron transport compound (ETM2) is between 2.5 and 2.8 eV;

and [LUMO (first electron transport layer) + LUMO (second electron transport layer)]/2 is between 2.85 and 3.15 eV;

The first electron transport compound includes one or more compounds having structures shown in general formula (1-1) to general formula (1-3).

The second electron transport compound includes compounds having structures represented by general formula (2-1) and general formula (2-2), or is composed of one or more of them.

In the general formula,

X ₁ -X ₉ are independently CR or N atoms;

Z ₁ -Z ₈ are independently represented by CR or N atoms;

Y represents a single bond, -O-, -S-, -CR ₁₀ R ₁₁ - or -NR ₁₂ ;

L ₁ to _{L 4} each independently represent a single bond, a C ₁ -C ₂₀ alkylene group, a substituted or unsubstituted C ₅ -C ₆₀ arylene group, or a substituted or unsubstituted C ₂ -C ₆₀ heteroarylene group;

Ar ₁ to Ar ₈ are independently substituted or unsubstituted C ₅ -C ₆₀ aryl, or substituted or unsubstituted C ₂ -C ₆₀ heteroaryl;

Cy represents a substituted or unsubstituted C ₂ -C ₆₀ heteroaryl group; R represents a hydrogen atom, a substituted or unsubstituted phenyl group, a naphthyl group, a biphenyl group, or a pyridyl group, and the substituted substituent represents one or more of a phenyl group, a methyl group, an ethyl group, a propyl group, and a butyl group;

R ₁ -R ₇ are independently hydrogen, substituted or unsubstituted C ₅ -C ₆₀ aryl, or substituted or unsubstituted C ₂ -C ₆₀ heteroaryl; R ₈ is substituted terphenyl, or a structure represented by general formula (3)

R ₉ is represented by the structure shown in general formula (3);

R ₁₀ to _{R 12} are independently C _1-20 alkyl, substituted or unsubstituted C _5-60 aryl or substituted or unsubstituted C ₂ -C ₆₀ heteroaryl;

wherein R ₁₃ and R ₁₄ are independently represented by a halogen atom, a substituted or unsubstituted C ₁ -C ₂₀ alkyl group, a substituted or unsubstituted C ₅ -C ₆₀ aryl group, or a substituted or unsubstituted C ₂ -C ₆₀ heteroaryl group, and optionally R ₁₃ and R ₁₄ are connected by a single bond to form a 5-7 membered ring;

R ₁₅ and R ₁₆ are independently a hydrogen atom, a halogen atom, a cyano group,

The general formula (3-1), the general formula (3-2), and the general formula (3-3) are connected to form a ring with the general formula (3) through "*",

wherein Y ₁ -Y ₃ are independently -O-, -S-, -CR ₁₇ R ₁₈ - or NR ₁₉ ;

The definition of R ₁₇ -R ₁₉ is consistent with the definition range of R ₁₀ -R ₁₂ ;

The prefix "substituted or unsubstituted" used before a group, if not specified, means that the group is optionally substituted with at least one selected from cyano, halogen, C _1-20 alkyl, C _2-20 alkenyl, C _6-30 aryl, C _2-30 heteroaryl; or is unsubstituted.

2 . The electroluminescent device according to claim 1 , wherein in the general formula, L ₁ to L ₄ are independently phenylene, biphenylene or terphenylene.

3. The electroluminescent device according to claim 1, wherein in the general formula, Ar ₁ to Ar ₈ are independently phenyl, naphthyl, biphenyl, terphenyl, anthracenyl, phenanthryl, pyridyl, pyrimidyl, furanyl, benzofuranyl, dibenzofuranyl, imidazolyl, benzimidazolyl, indolyl, benzindolyl, carbazolyl, N-phenylcarbazolyl,

4. The electroluminescent device according to claim 1, wherein in the general formula, Cy represents a pyridyl group, a pyrimidyl group, a triazine group, an imidazolyl group, a benzimidazolyl group, an indolyl group, a benzindolyl group, a carbazolyl group, an N-phenylcarbazolyl group, a furyl group, a benzofuranyl group, a dibenzofuranyl group, a quinolyl group, an isoquinolyl group or

5. The electroluminescent device according to claim 1, wherein in the general formula, _R1 to _R7 are independently naphthyl, anthracenyl, phenanthrenyl, pyrenyl,

6. The electroluminescent device according to claim 1, wherein, in the general formula, R ₈ is

7. The electroluminescent device according to claim 1, wherein, in the general formula, R ₉ is

8. The organic electroluminescent device according to claim 1, wherein the first electron transport compound comprises a compound having the following structure:

9. The organic electroluminescent device according to claim 1, wherein the second electron transport compound comprises or consists of a compound having the following structure:

10. The organic electroluminescent device according to claim 1, wherein the hole transport region comprises a hole injection layer, a hole transport layer and an electron blocking layer in sequence, wherein the hole injection layer is located between the anode and the hole transport layer, the hole transport layer is located between the hole injection layer and the electron blocking layer, and the electron blocking layer is located between the light-emitting layer and the hole transport layer.

11 . The organic electroluminescent device according to claim 1 , wherein the electron transport region further comprises an electron injection layer, and the electron injection layer is located between the first electron transport layer and the cathode layer.

12 . The organic electroluminescent device according to claim 1 , wherein the first electron transport layer is doped with the first electron transport compound and Liq.

13 . The organic electroluminescent device according to claim 1 , wherein the second electron transport layer is composed of one or more compounds selected from the second electron transport compound.

14 . The organic electroluminescent device according to claim 1 , wherein the second electron transport layer is composed of a compound selected from the second electron transport compound.

15 . The organic electroluminescent device according to claim 12 , wherein a weight ratio of the first electron transport compound to Liq ranges from 1:10 to 10:1.

16 . The organic electroluminescent device according to claim 15 , wherein a weight ratio of the first electron transport compound to Liq ranges from 1:9 to 9:1.

17 . The organic electroluminescent device according to claim 16 , wherein a weight ratio of the first electron transport compound to Liq ranges from 2:8 to 8:2.

18. A method for preparing an organic electroluminescent device according to any one of claims 1 to 17, comprising laminating the anode, organic layer and cathode of claims 1 to 17, or laminating the cathode, organic layer and anode of claims 1 to 17, on a substrate in succession, wherein the lamination is performed by vacuum evaporation at a temperature of 100 to 500°C, at a vacuum degree of 10 ^-8 to 10 ^-2 torr and at a rate of .

19. A display device comprising the organic electroluminescent device according to any one of claims 1 to 17.

20 . The display device according to claim 19 , wherein when comprising a plurality of devices, the devices are stacked and combined horizontally or vertically.

21. The display device according to claim 20, wherein the display device comprises devices each having an organic light-emitting material layer of three colors: blue, green and red, each of the devices having an electron blocking layer of the same or different film thickness, and the materials of the electron blocking layers are the same or different.