Organic electroluminescent device

Abstract

The present invention relates to an organic electroluminescent device, and more particularly to an organic electroluminescent device capable of effectively blocking electrons and an ultra-thick organic electroluminescent device. The organic electroluminescent device capable of effectively blocking electrons of the present invention can clearly improve the problem of the deterioration of device stability due to charge imbalance in the organic electroluminescent device, and based on this, the thickness of the hole transport layer can be increased, and a thicker device is advantageous in reducing the impact of substrate unevenness and residues on device performance, which is of great significance in improving the yield of industrial OLED panels and lighting. The present invention can improve the thickness of the conventional organic electroluminescent device, which has a thickness of 100 nm to 200 nm, to a micron level by using an ohmic contact method with better injection effect, and a thicker device is advantageous in reducing the impact of substrate unevenness and residues on device performance, which can improve the yield problem of industrial OLED manufacturing, especially in the field of large panels that are currently difficult to manufacture.

Description

Detailed Description of the Invention

[0001] This application claims priority to a prior application, filed with the State Intellectual Property Office of the People's Republic of China on January 27, 2022, bearing application number 2022101015371 and entitled "Organic electroluminescent device." This application claims priority to a prior application, filed with the State Intellectual Property Office of the People's Republic of China on January 27, 2022, bearing application number 2022101029317 and entitled "Organic electroluminescent device for effectively blocking electrons." The above two prior applications are incorporated herein by reference in their entireties.

[0002] [Technical Field] The present invention relates to the field of organic electroluminescent devices, and more particularly to organic electroluminescent devices that can improve hole injection into a hole transport layer and can effectively block electrons.

[0003] [Background technology] The phenomenon of organic electroluminescence was first discovered in 1963 by Professor Pope, who applied a voltage of several hundred volts to both sides of an anthracene crystal. By 1987, Den Seiun and his colleagues at Kodak in the United States had fabricated a two-layer device using vacuum deposition, which enabled the device brightness to reach 1000 cd / m. 2 The operating voltage at this temperature is less than 10 V, demonstrating the feasibility of commercial use of organic electroluminescent devices. Organic electroluminescent devices have many advantages, such as self-luminescence, wide viewing angles, fast response speed, and flexibility, so many scientific research institutes are focusing on research into organic light-emitting diodes (OLEDs).

[0004] After more than 30 years of development, organic electroluminescent devices have achieved commercial production and are steadily increasing their market share in the display and lighting industries. Conventional OLED devices use organic materials as transport layers, which typically have relatively low charge mobility. To inject more charge and maintain a balance between electrons and holes, OLED devices typically have a thickness of 100 to 200 nm. Extremely thin layers are susceptible to substrate irregularities, reducing product yields, especially in devices fabricated on large areas. The typical solution is to increase the thickness of the hole transport layer to reduce the impact of substrate residues on the light-emitting layer. However, the resulting charge imbalance reduces device stability, primarily due to slow hole transport, which allows excess electrons to leak into the hole transport layer and form holes and excitons, potentially causing chemical decomposition of the hole transport layer material. Resolving the problem of reduced device stability caused by charge imbalance in thick-film devices is a key driver of improved OLED device yields.

[0005] The thickness of an OLED device is typically 100 nm to 200 nm. Because the organic materials used in OLEDs lack continuous energy bands, electrons can only move by jumping between groups with conjugated structures, resulting in relatively low mobility. Furthermore, the energy barrier for charge injection in OLEDs limits the magnitude of current. Industrial production of such thin devices, especially in large-area manufacturing processes, faces the problem of reduced yield due to substrate contamination. Therefore, fabricating thicker organic electroluminescent devices is an effective solution to the impact of substrate residue on devices, and is an issue that currently requires further investigation.

[0006] Summary of the Invention In order to overcome the drawbacks of the prior art, the present invention provides an organic electroluminescent device, particularly an organic electroluminescent device capable of improving hole injection into a hole transport layer, the organic electroluminescent device comprising an anode, an anode modification layer, an organic interface layer, and a hole transport layer, the anode modification layer being disposed on a surface of the anode, the anode modification layer, the organic interface layer, and the hole transport layer being sequentially disposed, the anode modification layer comprising a metal oxide, the organic interface layer comprising an organic interface material, and the hole transport layer comprising a hole transport material, wherein the work function of the metal oxide is 6 eV to 7 eV, and the HOMO energy level of the organic interface material is greater than that of the hole transport material by 0.2 eV or more.

[0007] In order to overcome the drawbacks of the prior art, the present invention provides an organic electroluminescent device, particularly an organic electroluminescent device capable of effectively blocking electrons, comprising a hole transport layer, an electron capture layer, and an electron blocking layer, the hole transport layer, the electron capture layer, and the electron blocking layer being sequentially connected, the hole transport layer comprising a hole transport material, the electron capture layer comprising an electron capture material, and the electron blocking layer comprising an electron blocking material, wherein the difference in LUMO energy level between the electron capture material and the HOMO energy level between the hole transport material is −0.5 eV to 0.5 eV, and the difference in LUMO energy level between the electron capture material and the HOMO energy level between the electron blocking material is −0.5 eV to 0.5 eV.

[0008] Beneficial Effects: (1) The present invention provides an organic electroluminescent device, particularly an organic electroluminescent device capable of improving hole injection into an ultra-thick hole transport layer. The ohmic contact method used in the present invention can significantly improve the hole injection ability into the hole transport layer, and compared to conventional hole injection layers, the ohmic contact method has a better injection effect. The present invention uses the ohmic contact method with better injection effect to improve the thickness of organic electroluminescent devices from conventional thicknesses of 100 nm to 200 nm to micron-level thicknesses. Thicker devices are advantageous in reducing the impact of substrate irregularities and residues on device performance, thereby improving the yield problem of industrial OLED manufacturing, especially in the field of large panels, which are currently difficult to manufacture.

[0009] (2) The present invention provides an organic electroluminescent device, particularly an organic electroluminescent device that can effectively block electrons. The present invention significantly improves the problem of reduced device stability due to charge imbalance in the organic electroluminescent device. Based on this, the thickness of the hole transport layer can be increased, and organic electroluminescent devices with a conventional thickness of 100 nm to 200 nm can be improved to a thickness on the micron level. Thicker devices are advantageous in reducing the impact of substrate irregularities and residues on device performance, which is of great significance for improving the yield of industrial OLED panels and lighting.

[0010] BRIEF DESCRIPTION OF THE DRAWINGS 1 is a structural diagram of an organic electroluminescent device capable of effectively blocking electrons according to the present invention, in which HIL is a hole injection layer, HTL is a hole transport layer, EBL is an electron blocking layer, EML is an emitting layer, HBL is a hole blocking layer, ETL is an electron transport layer, and Liq is an electron injection layer.

[0011] FIG. 2 illustrates the effect of an electron capture layer on a hole single carrier device.

[0012] FIG. 3 illustrates the effect of an electron trapping layer on an electronic single-carrier device.

[0013] 4 is a structural diagram of the ultra-thick organic electroluminescent device of the present invention, in which ITO is the anode, MoO3 is the anode modification layer, Interlayer is the organic interface layer, HTL is the hole transport layer, EBL is the electron blocking layer, EML is the light emitting layer, HBL is the hole blocking layer, ETL is the electron transport layer, Liq is the electron injection layer, and Al is the cathode.

[0014] FIG. 5 is a comparison of hole injection with different hole injection layers in Example 7.

[0015] [Mode for Carrying Out the Invention] <Organic electroluminescent device, particularly an organic electroluminescent device capable of improving hole injection into an ultra-thick hole transport layer> The present invention provides an organic electroluminescent device whose total thickness can reach the micron level. The present invention uses a metal oxide as an anode modification layer and inserts an organic interface layer between the anode modification layer and the hole transport layer, thereby achieving ohmic contact between the anode and the hole transport layer (replacing the existing hole injection layer with the anode modification layer and the organic interface layer). This structure enhances hole injection capability. Furthermore, the present invention fabricates an organic electroluminescent device with a micron-level thickness by increasing the thickness of the hole transport layer. This ultra-thick organic electroluminescent device (having a micron-level thickness) maintains the same device performance as a thin organic electroluminescent device (having a device thickness of 100 nm to 200 nm) and has a very stable device life. Therefore, the present invention allows the device thickness to be increased without affecting the performance of the organic electroluminescent device. This ultra-thick organic electroluminescent device further reduces the impact of substrate residue on the light-emitting layer, thereby improving the manufacturing yield of organic electroluminescent devices.

[0016] One embodiment of the present invention provides an organic electroluminescent device, particularly an ultra-thick organic electroluminescent device, which comprises an anode, an anode modification layer, an organic interface layer, and a hole transport layer. The anode modification layer is disposed on a surface of the anode, and the anode modification layer, the organic interface layer, and the hole transport layer are sequentially disposed. The anode modification layer comprises a metal oxide, the organic interface layer comprises an organic interface material, and the hole transport layer comprises a hole transport material, wherein the work function of the metal oxide is 6 eV to 7 eV, and the HOMO energy level of the organic interface material is greater than that of the hole transport material by 0.2 eV or more.

[0017] According to an embodiment of the present invention, the HOMO energy level of the organic interface material is greater than the HOMO energy level of the hole transport material, and the difference is 0.2 eV, 0.3 eV, 0.4 eV, 0.5 eV, 0.6 eV, 0.7 eV, etc. or more.

[0018] According to an embodiment of the present invention, in the organic electroluminescent device, ohmic contact between the anode and the hole transport layer can be achieved by disposing the anode modifying layer and the organic interface layer.

[0019] Specifically, when the work function of the metal oxide is 6 eV to 7 eV, and the HOMO energy level of the organic interface material is greater than that of the hole transport material by at least 0.2 eV, the organic interface layer inserted between the anode modifying layer and the hole transport layer matches the HOMO energy levels of the hole transport materials in the anode and hole transport layer, and the organic interface layer is so thin that holes move to the hole transport layer by tunneling, eliminating the barrier to hole injection from the anode to the hole transport layer and achieving ohmic contact between the anode and the hole transport layer, thereby improving hole injection capability. Therefore, excellent device performance and stability can be maintained even when the hole transport layer is thick.

[0020] According to an embodiment of the present invention, the organic electroluminescent device further comprises an electron blocking layer, an emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode, the electron blocking layer being disposed on the hole transport layer, and the electron blocking layer, the emitting layer, the hole blocking layer, the electron transport layer, the electron injection layer, and the cathode being disposed in sequence.

[0021] According to an embodiment of the present invention, the organic electroluminescent device includes an anode, an anode modifying layer, an organic interfacial layer (interlayer), a hole transporting layer (HTL), an electron blocking layer (EBL), an emitting layer (EML), a hole blocking layer (HBL), an electron transporting layer (ETL), an electron injection layer, and a cathode, which are sequentially connected to one another.

[0022] According to an embodiment of the present invention, the hole transport layer comprises a hole transport material, and the hole transport material is selected from materials having hole transport ability, including at least one group selected from the group consisting of a carbazole group, a triphenylamine group, a fluorenyl group, and a thiophene group.

[0023] According to an embodiment of the present invention, the thickness of the hole transport layer is 50 nm to 3000 nm, preferably 50 nm to 1800 nm, for example, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1200 nm, 1300 nm, 1500 nm, 1800 nm, 2000 nm, 2200 nm, 2500 nm, 2800 nm, or 3000 nm.

[0024] <Organic electroluminescent device, particularly an organic electroluminescent device capable of effectively blocking electrons> The present invention provides an organic electroluminescent device that effectively solves the problem of reduced device stability due to an imbalance between hole and electron transport. The present invention provides an electron capture layer inserted between a hole transport layer and an electron blocking layer in an organic electroluminescent device. The electron capture layer has a relatively deep LUMO energy level that matches the HOMO energy levels of the hole transport layer and the electron blocking layer (the difference in energy levels may be -0.5 eV to 0.5 eV). The electron capture layer inserted in the present invention does not inhibit hole transport but has a significant inhibitory effect on the LUMO of excess electrons in the hole transport layer. The present invention effectively captures excess electrons, preventing them from being transported to the LUMO energy level of the hole transport layer. This effectively avoids the problem of exciton formation in the hole transport layer due to carrier imbalance, and significantly improves the stability of the organic electroluminescent device. Based on this, the present invention allows the thickness of the hole transport layer to be increased to fabricate an ultra-thick device while still achieving excellent device performance and stability.

[0025] One embodiment of the present invention provides an organic electroluminescent device, particularly an organic electroluminescent device capable of effectively blocking electrons. The organic electroluminescent device includes a hole transport layer, an electron capture layer, and an electron blocking layer, which are sequentially connected to one another. The hole transport layer includes a hole transport material, the electron capture layer includes an electron capture material, and the electron blocking layer includes an electron blocking material. A difference in LUMO energy level between the electron capture material and the HOMO energy level of the hole transport material is −0.5 eV to 0.5 eV, and a difference in LUMO energy level between the electron capture material and the HOMO energy level of the electron blocking material is −0.5 eV to 0.5 eV.

[0026] According to an embodiment of the present invention, by matching the LUMO energy level of the electron trapping layer with the HOMO energy level of the hole transporting layer and the HOMO energy level of the electron blocking layer, the electron trapping layer can effectively inhibit the transport of electrons from the electron blocking layer to the hole transporting layer. That is, the electron trapping layer can effectively capture excess electrons in the device, which leak into the hole transporting layer to form excitons with holes, causing chemical decomposition of the hole transporting layer, while not affecting the transport of holes from the hole transporting layer to the electron blocking layer.

[0027] The electron trapping layer has a LUMO energy level that is deeper than the hole transporting layer and the electron blocking layer, and therefore can effectively block excess electrons on the electron blocking layer and prevent them from being transported to the LUMO of the hole transporting layer.

[0028] According to an embodiment of the present invention, the hole transport layer comprises a hole transport material, and the hole transport material is selected from materials having hole transport ability, including at least one group selected from the group consisting of a carbazole group, a triphenylamine group, a fluorenyl group, and a thiophene group.

[0029] According to an embodiment of the present invention, the thickness of the hole transport layer is 50 nm to 1800 nm, for example, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1200 nm, 1300 nm, 1500 nm, or 1800 nm, and the hole transport layer has excellent device performance and stability under the action of the electron capture layer.

[0030] According to an embodiment of the present invention, the introduction of the electron capture layer can effectively suppress the accumulation of excess electrons in the hole transport layer, effectively suppress the generation of excitons in the hole transport layer, and significantly improve the stability of the organic electroluminescent device.

[0031] According to an embodiment of the present invention, the electron capture layer comprises an electron capture layer material, which is selected from organic materials or alkaloids containing strong electron-withdrawing groups such as CN, F, Cl, etc. According to an embodiment of the present invention, the thickness of the electron capture layer is 1 nm to 100 nm, preferably 2 nm to 10 nm, for example, 1 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 80 nm, 90 nm, or 100 nm.

[0032] According to an embodiment of the present invention, the organic electroluminescent device further comprises an anode and a hole injection layer, the hole injection layer being disposed on the hole transport layer, and the anode being disposed on the hole injection layer.

[0033] According to an embodiment of the present invention, the hole injection layer comprises a hole injection material, which is a hole injection material known in the art for use in organic electroluminescent devices. The thickness of the hole injection layer is 1 nm to 50 nm, preferably 5 nm to 10 nm, for example, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm.

[0034] According to an embodiment of the present invention, the hole injection layer comprises an anode modification layer and an organic interface layer, the anode modification layer being disposed on the surface of the anode, the organic interface layer being disposed on the surface of the hole transport layer, the anode modification layer comprising a metal oxide, and the organic interface layer comprising an organic interface material, wherein the metal oxide has a work function of 6 eV to 7 eV, and the HOMO energy level of the organic interface material is greater than that of the hole transport material by 0.2 eV or more.

[0035] According to an embodiment of the present invention, the organic electroluminescent device further comprises an emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode, the emitting layer being disposed on the electron blocking layer, and the emitting layer, hole blocking layer, electron transport layer, electron injection layer, and cathode being sequentially connected to one another.

[0036] According to an embodiment of the present invention, the organic electroluminescent device includes an anode, a hole injection layer (HIL), a hole transport layer (HTL), an electron capture layer (interlayer), an electron blocking layer (EBL), an emitting layer (EML), a hole blocking layer (HBL), an electron transport layer (ETL), an electron injection layer (EIL), and a cathode, which are sequentially connected to one another.

[0037] <Anode modification layer in the above two organic electroluminescent devices> According to an embodiment of the present invention, the anode modification layer contains a metal oxide selected from at least one of MoO3, WoO3, and V2O5, and the thickness of the anode modification layer is 5 nm to 100 nm, preferably 5 nm to 20 nm, for example, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 80 nm, 90 nm, or 100 nm.

[0038] <Organic interface layer in the above two organic electroluminescent devices> According to an embodiment of the present invention, the organic interface layer comprises an organic interface material, and the selection of the organic interface material is mainly determined by the HOMO energy level of the hole transport material in the hole transport layer, and the HOMO energy level of the organic interface material is higher than the HOMO energy level of the hole transport material in the hole transport layer, and the difference between the HOMO energy level is 0.2 eV or more.

[0039] According to an embodiment of the present invention, the thickness of the organic interface layer is 1 nm to 20 nm, preferably 3 nm to 4 nm, for example, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 12 nm, 15 nm, 18 nm or 20 nm.

[0040] <Electron Blocking Layer in the Above Two Organic Electroluminescent Devices> According to an embodiment of the present invention, the electron-blocking layer comprises an electron-blocking material, which is selected from materials having hole-transporting and electron-blocking capabilities, including at least one group selected from the group consisting of carbazole, triphenylamine, dibenzothiophene, and dibenzofuran.

[0041] According to an embodiment of the present invention, the thickness of the electron blocking layer is 1 nm to 50 nm, preferably 1 nm to 20 nm, for example, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm.

[0042] <Light-emitting layers in the above two organic electroluminescent devices> According to an embodiment of the present invention, the light-emitting layer comprises a light-emitting material, which is a light-emitting material known in the art for use in organic electroluminescent devices. The thickness of the light-emitting layer is 1 nm to 50 nm, preferably 5 nm to 30 nm, for example, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm.

[0043] <Hole-blocking layer in the above two organic electroluminescent devices> According to an embodiment of the present invention, the hole-blocking layer comprises a hole-blocking material, which is a hole-blocking material known in the art for use in organic electroluminescent devices. The thickness of the hole-blocking layer is 1 nm to 50 nm, preferably 5 nm to 20 nm, for example, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm.

[0044] <Electron transport layer in the above two organic electroluminescent devices> According to an embodiment of the present invention, the electron transport layer comprises an electron transport material, which is known in the art for use in organic electroluminescent devices. The thickness of the electron transport layer is 20 to 200 nm, preferably 30 to 50 nm, for example, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, or 200 nm.

[0045] <Electron injection layer in the above two organic electroluminescent devices> According to an embodiment of the present invention, the electron injection layer comprises an electron injection material, which is known in the art for use in organic electroluminescent devices, and has a thickness of 1 nm to 5 nm, preferably 1 nm to 2 nm, for example, 1 nm, 2 nm, 3 nm, 4 nm, or 5 nm.

[0046] <The above two organic electroluminescent devices> According to an embodiment of the present invention, the thickness of the organic electroluminescent device is 50 nm to 3000 nm, for example, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1200 nm, 1300 nm, 1500 nm, 1800 nm, 2000 nm, 2200 nm, 2500 nm, 2800 nm, or 3000 nm. An organic electroluminescent device having such a thickness, particularly an organic electroluminescent device having a thickness of 200 nm to 3000 nm, can still maintain excellent device performance and stability.

[0047] According to an embodiment of the present invention, the organic electroluminescent device may be an upright device or an inverted device.

[0048] According to an embodiment of the present invention, in the upright element, the anode includes an anode material selected from at least one of conductive oxides (ITO, ZnO, TCO, etc.), silver nanowires, graphene thin film, and metal grids (Ni, Au, Pt, Mo, Al, Ag, etc.). Preferably, the anode material is a metal or metal oxide with relatively high light transmittance and good conductivity, such as indium tin oxide (ITO), indium zinc oxide (ITZ), zinc oxide (ZnO), etc.

[0049] According to an embodiment of the present invention, for an upright element, the cathode includes a cathode material, and the cathode material is selected from metal materials with excellent conductivity, exemplarily selected from aluminum, magnesium, calcium, strontium, magnesium-silver alloy, magnesium-aluminum alloy, aluminum-lithium alloy, and mixtures of the above metals or alloys with alkali metals such as lithium fluoride, lithium, cesium, calcium, etc. Preferably, the cathode material is selected from an electrode layer made of a metal material with excellent conductivity, such as aluminum, magnesium, calcium, or strontium metal, magnesium-silver alloy, magnesium-aluminum alloy, aluminum-lithium alloy, etc., and mixtures of the above metals or alloys with alkali metals such as lithium fluoride, lithium, cesium, calcium, etc.

[0050] According to an embodiment of the present invention, for an inverted device, the cathode material can be selected from metals or metal oxides with relatively high light transmittance and good electrical conductivity, such as indium tin oxide (ITO), indium zinc oxide (ITZ), zinc oxide (ZnO), etc.

[0051] According to an embodiment of the present invention, for an inverted element, the anode material can be selected from metals with good electrical conductivity and relatively high reflectivity, such as aluminum, silver, gold, and the like.

[0052] According to an embodiment of the present invention, the light emission type of the organic electroluminescent device may be bottom emission, top emission, transmissive emission, or the like.

[0053] <Method for manufacturing the organic electroluminescent device> The present invention further provides a method for producing the organic electroluminescent device obtained by vapor deposition, film stretching, spin coating, or inkjet printing.

[0054] <Method for Improving Hole Injection Ability into Hole Transport Layer> The present invention further provides a method for improving hole injection ability into a hole transport layer, the method comprising the steps of: an anode modifying layer is disposed on a surface of an anode, and an organic interface layer and a hole transport layer are sequentially disposed on the anode modifying layer, the anode modifying layer comprising a metal oxide, the organic interface layer comprising an organic interface material, and the hole transport layer comprising a hole transport material, wherein the metal oxide has a work function of 6 eV to 7 eV; The HOMO energy level of the organic interface material is greater than the HOMO energy level of the hole transport material by at least 0.2 eV.

[0055] <Method for suppressing electron accumulation in thick-film organic electroluminescent devices> The present invention further provides a method for suppressing electron accumulation in a thick-film organic electroluminescent device, the method comprising the steps of: An electron capture layer is inserted between the hole transport layer and the electron blocking layer, the hole transport layer comprising a hole transport material, the electron capture layer comprising an electron capture material, and the electron blocking layer comprising an electron blocking material, the difference between the LUMO energy level of the electron capture material and the HOMO energy level of the hole transport material being −0.5 eV to 0.5 eV, and the difference between the LUMO energy level of the electron capture material and the HOMO energy level of the electron blocking material being −0.5 eV to 0.5 eV.

[0056] The organic electroluminescent device manufactured according to the present invention can reduce the influence of residues on the substrate on the light-emitting layer by increasing the thickness of the hole transport layer, and can maintain high-efficiency device performance and stability due to its excellent electron blocking ability.

[0057] The present invention will be described in more detail below with reference to specific examples. It should be understood that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the claims of the present invention. Any technology realized based on the above content of the present invention is included in the scope of the claims of the present invention.

[0058] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods, and the reagents, materials, etc. used in the following examples are all commercially available unless otherwise specified.

[0059] Non-limiting examples of electron trapping materials, hole transporting materials, electron blocking materials, and organic interface materials are listed below.

[0060] Electron capture materials include:

[0061] [ka]

[0062] Hole transport materials include:

[0063] [ka]

[0064] [ka]

[0065] [ka]

[0066] n is the degree of polymerization of the monomer and is an integer greater than 1.

[0067] Electron blocking materials include:

[0068] [ka]

[0069] [ka]

[0070] n is the degree of polymerization of the monomer and is an integer greater than 1.

[0071] Organic interface materials include:

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] n is the degree of polymerization of the monomer and is an integer greater than 1.

[0076] The hole single carrier device used in the following Examples 1 to 6 is composed of an anode, a hole injection layer (HIL), a hole transport layer (HTL), an electron capture layer (Interlayer), an electron blocking layer (EBL), a hole injection layer (HIL), and a cathode.

[0077] The electron single-carrier devices used in the following Examples 1 to 6 are composed of an anode, an electron transport layer (ETL), an electron capture layer (Interlayer), an electron blocking layer (EBL), an emitting layer (EML), a hole blocking layer (HBL), an electron transport layer (ETL), an electron injection layer (EIL), and a cathode.

[0078] The organic electroluminescent devices used in the following Examples 1 to 6 are composed of an anode, a hole injection layer (HIL), a hole transport layer (HTL), an electron capture layer (Interlayer), an electron blocking layer (EBL), an emitting layer (EML), a hole blocking layer (HBL), an electron transport layer (ETL), an electron injection layer (EIL), and a cathode.

[0079] The hole single-carrier element used in the following Examples 7 to 12 is composed of an anode, a hole injection layer (anode-modifying layer, organic interface layer), a hole transport layer (organic interface layer, anode-modifying layer), a hole injection layer, and a cathode, which are connected in sequence.

[0080] The organic electroluminescent device used in the following Examples 7 to 12 is composed of an anode, a hole injection layer (anode modifying layer, organic interface layer), a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode, which are arranged in this order.

[0081] The organic electroluminescent devices in Examples 1 to 6 below were manufactured as follows: The glass substrate coated with the patterned ITO transparent conductive layer was ultrasonically treated twice for 10 min each using a commercial detergent, deionized water, acetone, and ethanol, respectively. The substrate was then baked in an oven in a clean environment for 15 min, the oven temperature was set to 75 °C, and the substrate was subjected to ultraviolet light ozone treatment for 10 min. The substrate was then placed in an organic-metallic vacuum deposition chamber, and the pressure in the chamber was adjusted to 5 × 10 -4 After evacuation to less than Pa, the organic layers (hole injection layer, hole transport layer, electron capture layer, electron blocking layer, light-emitting layer, hole blocking layer, and electron transport layer) are sequentially evaporated at a rate of 1–2 Å / s, Liq is evaporated at a rate of 0.05 Å / s, and an Al electrode (cathode) is evaporated at a rate of 5 Å / s.

[0082] The organic electroluminescent devices in Examples 7 to 12 below were manufactured as follows: The glass substrate coated with the patterned ITO transparent conductive layer was ultrasonically treated twice for 10 min each using a commercial detergent, deionized water, acetone, and ethanol, respectively. The substrate was then baked in an oven in a clean environment for 15 min, the oven temperature was set to 75 °C, and the substrate was subjected to ultraviolet light ozone treatment for 10 min. The substrate was then placed in an organic-metallic vacuum deposition chamber, and the pressure in the chamber was adjusted to 5 × 10 -4 After evacuation to less than Pa, a hole injection layer (anode modification layer, organic interface layer), a hole transport layer, an electron blocking layer, an emitting layer, and optionally a hole blocking layer and an electron transport layer were sequentially deposited at a rate of 1 to 12 Å / s, Liq was deposited at a rate of 0.05 Å / s, and an Al electrode was deposited at a rate of 5 Å / s. The structural formula of the resulting organic electroluminescent device is shown in Figure 4.

[0083] The performance measurements of the organic electroluminescent devices in Examples 1 to 12 below were as follows: (1) The film thickness of the element is measured using a step gauge.

[0084] (2) Apply a forward DC current to both sides of the fabricated device electrodes, measure the current-voltage characteristics using a Keithley 2400 digital source meter, measure the current-luminance characteristics of the device using a CS200, measure the spectral characteristics using a PR650 luminance meter, and test the device stability using an M6000 OLED life tester.

[0085] Example 1 A hole-single carrier device was fabricated using TAPC (4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline]) as a hole transport layer, MoO3 / SimCP2 (bis[3,5-bis(9H-carbazol-9-yl)phenyl]diphenylsilane) as a hole injection layer, HAT-CN (2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene) as an electron capture layer, NHT210 (N,N-bis([1,1'-biphenyl]-4-yl)-3'-(dibenzo[b,d]furan-4-yl)-[1,1'-biphenyl]-4-amine) as an electron blocking layer, Al as a cathode, and ITO as an anode.

[0086] The specific structure of the hole single carrier device a is as follows: ITO(150 nm) / MoO3(10 nm) / SimCP2(3 nm) / TAPC(1000 nm) / NHT210(10 nm) / SimCP3(3 nm) / MoO3(10 nm) / Al(100 nm).

[0087] The specific structure of the hole single carrier device b is as follows: ITO(150 nm) / MoO3(10 nm) / SimCP2(3 nm) / TAPC(1000 nm) / HAT-CN(4 nm) / NHT210(10 nm) / SimCP3(3 nm) / MoO3(10 nm) / Al(100 nm).

[0088] The JV parameters of the devices are as follows: at a driving voltage of 5 V, the current density of the hole single-carrier device a without HAT-CN is 30.6 mA / cm 2 The hole single-carrier device b with a 4 nm thick HAT-CN layer had a current density of 29.7 mA / cm 2 and is shown in Figure 2.

[0089] A comparison between the hole single-carrier device a and the hole single-carrier device b reveals that HAT-CN does not inhibit hole transport.

[0090] Example 2 ITO was used as the anode, ET225 (2-(3-(phenanthrene-9-yl)-5-(pyridin-3-yl)phenyl)-4,6-diphenyl-1,3,5-triazine) as the electron transport layer, HAT-CN as the electron capture layer, NHT210 as the electron blocking layer, and BH513:4%BD348 as the emitting layer (the main body of the emitting layer was BH513 (9-(naphthalen-1-yl)-10-(4-(naphthalen-2-yl)phenyl)anthracene), and the main body was BD348 (N1 ,N1,N6,N6-tetrakis(4-methyl-[1,1'-biphenyl]-3-yl)pyrene-1,6-diamine)), ET164 (9,9'-(5-(6-([1,1'-biphenyl]-4-yl)-2-phenylpyrimidin-4-yl)-1,3-phenylene)bis(9H-carbazole)) as a hole blocking layer, Liq (8-hydroxyquinolinolatolithium) as an electron injection layer, and Al as a cathode to fabricate an electronic single carrier device.

[0091] The structure of the electronic single carrier device a is as follows: ITO(150 nm) / ET225(30 nm) / NHT210(10 nm) / BH513:4%BD348(30 nm) / ET164(10 nm) / ET225(30 nm) / Liq(1 nm) / Al(100 nm).

[0092] The structure of the electronic single-carrier device b is as follows: ITO(150 nm) / ET225(30 nm) / HAT-CN(4 nm) / NHT210(10 nm) / BH513:4%BD348(30 nm) / ET164(10 nm) / ET225(30 nm) / Liq(1 nm) / Al(100 nm).

[0093] The JV parameters of the devices are as follows: at a driving voltage of 5 V, the current density of the electron single-carrier device a without HAT-CN is 3.8 mA / cm 2 The current density of the electron single-carrier device b with 4 nm of HAT-CN was 0.0009 mA / cm2 and is shown in Figure 3.

[0094] A comparison between the electron single-carrier device a and the electron single-carrier device b reveals that HAT-CN exerts a clear inhibitory effect on electron transport.

[0095] Example 3 An organic electroluminescent device is manufactured using ITO as the anode, MoO3 / SimCP2 as the hole injection layer, TAPC as the hole transport layer, HAT-CN as the electron capture layer, NHT210 as the electron blocking layer, BH513 as the main body of the light emitting layer, BD348 as the object, ET164 as the hole blocking layer, ET225 as the electron transport layer, Liq as the electron injection layer, and Al as the cathode.

[0096] The structure of the organic electroluminescent device a is as follows: ITO / MoO3(10 nm) / SimCP2(3 nm) / TAPC(950 nm) / NHT210(10 nm) / BH513:4%BD348(30 nm) / ET164(10 nm) / ET225(30 nm) / Liq(1 nm) / Al(100 nm).

[0097] The structure of the organic electroluminescent device b is as follows: ITO / MoO3(10 nm) / SimCP2(3 nm) / TAPC(950 nm) / HAT-CN(4 nm) / NHT210(10 nm) / BH513:4%BD348(30 nm) / ET164(10 nm) / ET225(30 nm) / Liq(1 nm) / Al(100 nm).

[0098] The device performance data for Example 3 are as follows:

[0099] [Table 1]

[0100] Example 4 The anode is ITO, the hole injection layer is MoO3 / SimCP2, the hole transport layer is TAPC, the electron capture layer is HAT-CN, the electron blocking layer is EBL012 (N-([1,1'-biphenyl]-4-yl)-N-(4-(dibenzo[b,d]thiophen-4-yl)phenyl)-[1,1'-biphenyl]-4-amine), and the main body of the light-emitting layer is RH(1-(3-([1,1'-biphenyl]-3-yl)quinoline). The compound is RD354 (bis(1-(3,5-dimethylphenyl)-6-isopropylisoquinoline)(3,7-diethylnonane-4,6-diketonato)iridium(III)), and the target is ET225 (electron transport layer), Liq (electron injection layer), and Al (cathode) to manufacture an organic electroluminescent device.

[0101] The structure of the organic electroluminescent device a is as follows: ITO / MoO3(10 nm) / SimCP2(3 nm) / TAPC(950 nm) / EBL012(10 nm) / RH:8%RD354(30 nm) / ET225(30 nm) / Liq(1 nm) / Al(100 nm).

[0102] The structure of the organic electroluminescent device b is as follows: ITO / MoO3(10 nm) / SimCP2(3 nm) / TAPC(950 nm) / HAT-CN(4 nm) / EBL012(10 nm) / RH:8%RD354(30 nm) / ET225(30 nm) / Liq(1 nm) / Al(100 nm).

[0103] The device performance data for Example 4 is as follows:

[0104] [Table 2]

[0105] Example 5 An organic electroluminescent device was fabricated using ITO as the anode, MoO3 / SimCP2 as the hole injection layer, TAPC as the hole transport layer, HAT-CN as the electron capture layer, EBL012 as the electron blocking layer, GH025 (2-(9-(4,6-diphenyl-1,3,5-triazin-2-yl)dibenzo[b,d]furan-2-yl)-9-phenyl-9H-carbazole) as the main body of the light emitting layer, GD617 (bis(2-phenylpyridine)(2-(methyl-d3)-8-(pyridin-2-yl)benzofuran[2,3-b]pyridine)iridium(III)) as the object, ET225 as the electron transport layer, Liq as the electron injection layer, and Al as the cathode.

[0106] The structure of the organic electroluminescent device a is as follows: ITO / MoO3(10 nm) / SimCP2(3 nm) / TAPC(950 nm) / EBL012(10 nm) / GH025:8%GD617(30 nm) / ET225(30 nm) / Liq(1 nm) / Al(100 nm).

[0107] The structure of the organic electroluminescent device b is as follows: ITO / MoO3(10 nm) / SimCP2(3nm) / TAPC(950 nm) / HAT-CN(4 nm) / EBL012(10 nm) / GH025:8%GD617(30 nm) / ET225(30 nm) / Liq(1 nm) / Al(100 nm).

[0108] The device performance data for Example 5 are as follows:

[0109] [Table 3]

[0110] Example 6 An organic electroluminescent device is manufactured by using ITO as the anode, MoO3 / SimCP2 as the hole injection layer, TAPC as the hole transport layer, EBL012 as the electron blocking layer, GH025 as the main body of the light emitting layer, TXO-PhCz as the object, ET164 as the hole blocking layer, ET225 as the electron transport layer, Liq as the electron injection layer, and Al as the cathode.

[0111] The structure of the organic electroluminescent device a is as follows: ITO / MoO3(10 nm) / SimCP2(3 nm) / TAPC(950 nm) / EBL012(10 nm) / GH025:10%TXO-PhCz(30 nm) / ET164(10 nm) / ET225(30 nm) / Liq(1 nm) / Al(100 nm).

[0112] The structure of the organic electroluminescent device b is as follows: ITO / MoO3(10 nm) / SimCP2(3 nm) / TAPC(950 nm) / HAT-CN(4 nm) / EBL012(10 nm) / GH025:10%TXO-PhCz(30 nm) / ET164(10 nm) / ET225(30 nm) / Liq(1 nm) / Al(100 nm).

[0113] The device performance data for Example 6 is as follows:

[0114] [Table 4]

[0115] From the performance test results of Examples 3 to 6, it can be seen that the introduction of the electron capture layer does not affect the performance of the device, but clearly improves the stability of the device.

[0116] Example 7 A hole single-carrier device was fabricated using ITO as the anode, TAPC (4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline]) as the hole transport layer, HAT-CN (2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene), MoO3 / SimCP2 (bis[3,5-bis(9H-carbazol-9-yl)phenyl]diphenylsilane), or MoO3 as the hole injection layer, and Al as the cathode. The work function of MoO3 is 6.7 eV, the HOMO energy level of SimCP2 is 6.1 eV, and the HOMO energy level of TAPC is 5.6 eV.

[0117] The structure of the hole single carrier device a is as follows: ITO(150 nm) / MoO3(10 nm) / TAPC(500 nm) / SimCP2(3 nm) / MoO3(10 nm) / Al(100 nm). The structure of the hole single carrier device b is as follows: ITO(150 nm) / HAT-CN(10 nm) / TAPC(500 nm) / SimCP2(3 nm) / MoO3(10 nm) / Al(100 nm).

[0118] The structure of the hole single carrier device c is as follows: ITO(150 nm) / MoO3(10 nm) / SimCP2(3 nm) / TAPC(500 nm) / SimCP2(3 nm) / MoO3(10 nm) / Al(100 nm).

[0119] The structure of the hole single carrier device d is as follows: ITO(150 nm) / TAPC(500 nm) / SimCP2(3 nm) / MoO3(10 nm) / Al(100 nm).

[0120] The JV parameters of the device are as follows: When the driving voltage is 7 V, the hole single carrier current density of device a is 1.43 mA / cm 2The current density of the single-carrier device c injected holes by MoO3 / SimCP2 was 329.21 mA / cm 2 The hole single carrier current density of device b injected by HAT-CN was 70.75 mA / cm 2 The current density of the hole single carrier device d, where the hole is directly injected by ITO, is 93.71 mA / cm 2 , as shown in Figure 5.

[0121] Compared with the above hole single-carrier devices, MoO3 / SimCP2 has better hole injection ability than the conventional hole injection layer.

[0122] Example 8 The anode is ITO, MoO3 / SimCP2 is the hole injection layer (MoO3 is the anode modification layer, and SimCP2 is the organic interface layer), TAPC is the hole transport layer, the electron blocking layer is EBL012 (N-([1,1'-biphenyl]-4-yl)-N-(4-(dibenzo[b,d]thiophen-4-yl)phenyl)-[1,1'-biphenyl]-4-amine), the main body of the emitting layer is RH (1-(3-([1,1'-biphenyl]-3-yl)quinoxalin-2-yl)-1H-1-azadibenzo[g,ij]naphtho[2,1,8-cde]azulene), and the substrate is RD354 (bis(1-(3,5-dimethylphenyl)-2-methyl-1H-biphenyl)-4-amine). )-6-isopropylisoquinoline)(3,7-diethylnonane-4,6-diketonato)iridium(III)), the hole blocking layer was ET164 (9,9'-(5-(6-([1,1'-biphenyl]-4-yl)-2-phenylpyrimidin-4-yl)-1,3-phenylene)bis(9H-carbazole)), the electron transport layer was ET225 (2-(3-(phenanthren-9-yl)-5-(pyridin-3-yl)phenyl)-4,6-diphenyl-1,3,5-triazine), the electron injection layer was Liq (8-hydroxyquinolinolatolithium), and the cathode was Al, to produce an organic electroluminescent device.

[0123] The structure of the organic electroluminescent device is as follows: ITO / MoO3 (10 nm) / SimCP2 (3 nm) / TAPC (x nm) / EBL012 (10 nm) / RH:8%RD354 (30 nm) / ET164 (10 nm) / ET225 (35 nm) / Liq (1 nm) / Al (100 nm), where the thickness of TAPC is 50 nm, 300 nm, 500 nm, 700 nm, 950 nm, 1300 nm, 1500 nm, and 1800 nm, respectively.

[0124] The device performance data for Example 8 is as follows:

[0125] [Table 5]

[0126] Example 9 The anode is ITO, MoO3 / SimCP2 is the hole injection layer (MoO3 is the anode modification layer, and SimCP2 is the organic interface layer), TAPC is the hole transport layer, the electron blocking layer is EBL012, the main body of the light emitting layer is GH025 (2-(9-(4,6-diphenyl-1,3,5-triazin-2-yl)dibenzo[b,d]furan-2-yl)-9-phenyl-9H-carbazole), the object is GD617 (bis(2-phenylpyridine)(2-(methyl-d3)-8-(pyridin-2-yl)benzofuran[2,3-b]pyridine)iridium(III)), the hole blocking layer is ET164, the electron transport layer is ET225, the electron injection layer is Liq, and the cathode is Al, to produce an organic electroluminescent device.

[0127] The structure of the organic electroluminescent device is as follows: ITO / MoO3 (10 nm) / SimCP2 (3 nm) / TAPC (x nm) / EBL012 (10 nm) / GH025:8%GD617 (30 nm) / ET164 (10 nm) / ET225 (30 nm) / Liq (1 nm) / Al (100 nm), where the thickness of TAPC is 50 nm, 300 nm, 500 nm, 700 nm, 950 nm, 1300 nm, 1500 nm, and 1800 nm, respectively.

[0128] The device performance data for Example 9 is as follows:

[0129] [Table 6]

[0130] Example 10 The anode is ITO, MoO3 / SimCP2 is the hole injection layer (MoO3 is the anode modification layer, and SimCP2 is the organic interface layer), TAPC is the hole transport layer, the electron blocking layer is NHT210, the main body of the light emitting layer is BH513 ((9-naphthalen-1-yl)-10-(4-(naphthalen-2-yl)phenyl)anthracene), the object is BD348 (N1,N1,N6,N6-tetrakis(4-methyl-[1,1'-biphenyl]-3-yl)pyrene-1,6-diamine), the hole blocking layer is ET164, the electron transport layer is ET225, the electron injection layer is Liq, and the cathode is Al, to produce an organic electroluminescent device.

[0131] The structure of the organic electroluminescent device is as follows: ITO / MoO3 (10 nm) / SimCP2 (3 nm) / TAPC (x nm) / NHT210 (10 nm) / BH513:4%BD348 (30 nm) / ET164 (10 nm) / ET225 (30 nm) / Liq (1 nm) / Al (100 nm), where the thickness of TAPC is 50 nm, 300 nm, 500 nm, 700 nm, 950 nm, 1300 nm, 1500 nm, and 1800 nm, respectively.

[0132] The device performance data for Example 10 is as follows:

[0133] [Table 7]

[0134] Example 11 The anode is ITO, MoO3 / SimCP2 is the hole injection layer (MoO3 is the anode modification layer, SimCP2 is the organic interface layer), TAPC is the hole transport layer, the electron blocking layer is EBL012, the main body of the light emitting layer is GH025, the object is TXO-PhCz, the hole blocking layer is ET164, the electron transport layer is ET225, the electron injection layer is Liq, and the cathode is Al to produce an organic electroluminescent device.

[0135] The structure of the organic electroluminescent device is as follows: ITO / MoO3 (10 nm) / SimCP2 (3 nm) / TAPC (x nm) / EBL012 (10 nm) / GH025:10%TXO-PhCz (30 nm) / ET164 (10 nm) / ET225 (30 nm) / Liq (1 nm) / Al (100 nm), where the thickness of TAPC is 50 nm, 300 nm, 500 nm, 700 nm, 950 nm, 1300 nm, 1500 nm, and 1800 nm, respectively. The device performance data for Example 11 is as follows:

[0136] [Table 8]

[0137] Example 12 The anode is ITO, MoO3 / SimCP2 is the hole injection layer (MoO3 is the anode modification layer, SimCP2 is the organic interface layer), TAPC is the hole transport layer, the electron blocking layer is EBL012, the main body of the light emitting layer is GH025, the object is TXO-TPA, the hole blocking layer is ET164, the electron transport layer is ET225, the electron injection layer is Liq, and the cathode is Al to produce an organic electroluminescent device.

[0138] The structure of the organic electroluminescent device is as follows: ITO / MoO3 (10 nm) / SimCP2 (3 nm) / TAPC (x nm) / EBL012 (10 nm) / GH025:10%TXO-TPA (30 nm) / ET164 (10 nm) / ET225 (30 nm) / Liq (1 nm) / Al (100 nm), where the thickness of TAPC is 50 nm, 300 nm, 500 nm, 700 nm, 950 nm, 1300 nm, 1500 nm, and 1800 nm, respectively.

[0139] The device performance data for Example 12 is as follows:

[0140] [Table 9]

[0141] From Example 7 above, when the driving voltage was 7 V, the current density injected into TAPC from ITO, MoO3, and HAT-CN was 93.71 mA / cm, respectively. 2 , 1.43 mA / cm 2 , 70.75 mA / cm 2 The current density injected from MoO3 / SimCP2 to TAPC was 329.21 mA / cm 2 This indicates that the ohmic contact method has superior hole injection capability. At the same time, it can be seen from Examples 8 to 12 that the devices fabricated with different thicknesses all have very good device performance, and comparing the device stability, it can be seen that when the device thickness is 50 nm, the device life is very short due to the influence of substrate roughness, but by increasing the device thickness, the stability is significantly improved.

[0142] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the scope of the claims of the present invention without departing from the spirit and principles of the present invention are included within the scope of the claims of the present invention. [Brief explanation of the drawings]

[0143] [Figure 1]1 is a structural diagram of an organic electroluminescent device capable of effectively blocking electrons according to the present invention, in which HIL is a hole injection layer, HTL is a hole transport layer, EBL is an electron blocking layer, EML is an emitting layer, HBL is a hole blocking layer, ETL is an electron transport layer, and Liq is an electron injection layer. [Figure 2] FIG. 1 illustrates the effect of an electron capture layer on a hole single carrier device. [Figure 3] FIG. 1 illustrates the effect of an electron capture layer on an electronic single-carrier device. [Figure 4] This is a structural diagram of the ultra-thick organic electroluminescent device of the present invention, in which ITO is the anode, MoO3 is the anode modification layer, Interlayer is the organic interface layer, HTL is the hole transport layer, EBL is the electron blocking layer, EML is the light emitting layer, HBL is the hole blocking layer, ETL is the electron transport layer, Liq is the electron injection layer, and Al is the cathode. [Figure 5] 10 is a comparison of hole injection with different hole injection layers in Example 7.

Claims

1. the anode modification layer is disposed on a surface of the anode, and the anode modification layer, the organic interface layer, and the hole transport layer are sequentially connected to each other; the anode modification layer comprises a metal oxide, the organic interface layer is an organic interface material, and the hole transport layer comprises a hole transport material; wherein the work function of the metal oxide is 6 eV to 7 eV; the HOMO energy level of the organic interface material is greater than the HOMO energy level of the hole transport material by 0.2 eV, 0.3 eV, 0.4 eV, 0.5 eV, 0.6 eV, or 0.7 eV; the thickness of the anode modification layer is 5 nm to 100 nm; and the thickness of the organic interface layer is 1 nm to 20 nm.

2. 2. The organic electroluminescent device according to claim 1, further comprising an electron blocking layer, an emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode, wherein the electron blocking layer is disposed on the hole transport layer, and the electron blocking layer, the emitting layer, the hole blocking layer, the electron transport layer, the electron injection layer, and the cathode are sequentially connected.

3. The organic interface material is: 【Chemistry 1】 2. The organic electroluminescent device according to claim 1, wherein n is a degree of polymerization of the monomer and is an integer greater than 1.

4. a hole transport layer, an electron capture layer, and an electron blocking layer, the hole transport layer, the electron capture layer, and the electron blocking layer being sequentially connected to each other; the hole transport layer comprises a hole transport material, the electron capture layer comprises an electron capture material, and the electron blocking layer comprises an electron blocking material; a difference between the LUMO energy level of the electron trapping material and the HOMO energy level of the hole transporting material is −0.5 eV to 0.5 eV, and a difference between the LUMO energy level of the electron trapping material and the HOMO energy level of the electron blocking material is −0.5 eV to 0.5 eV; Wherein, the organic electroluminescent device further comprises an anode and a hole injection layer, the hole injection layer being disposed on the hole transport layer, and the anode being disposed on the hole injection layer; Wherein, the hole injection layer includes an anode modifying layer and an organic interface layer, the anode modifying layer is disposed on the surface of the anode, and the organic interface layer is disposed on the surface of the hole transport layer; the anode modification layer comprises a metal oxide, and the organic interface layer is an organic interface material; wherein the work function of the metal oxide is 6 eV to 7 eV; the HOMO energy level of the organic interfacial material is greater than the HOMO energy level of the hole transport material by 0.2 eV, 0.3 eV, 0.4 eV, 0.5 eV, 0.6 eV, or 0.7 eV; The organic electroluminescent device, wherein the thickness of the anode modification layer is 5 nm to 100 nm, and the thickness of the organic interface layer is 1 nm to 20 nm.

5. 5. The organic electroluminescent device according to claim 4, further comprising an emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode, wherein the emitting layer is disposed on the electron blocking layer, and the emitting layer, the hole blocking layer, the electron transport layer, the electron injection layer, and the cathode are sequentially connected.

6. the electron capture layer comprises an electron capture layer material, the electron capture layer material being selected from organic materials or alkaloids containing strong electron-withdrawing groups such as CN, F, and Cl; and / or the electron capture layer has a thickness of 1 nm to 100 nm.

7. The organic electroluminescent device according to any one of claims 1 to 6, wherein the organic electroluminescent device has a thickness of 50 nm to 3000 nm.

8. the hole transport layer comprises a hole transport material, the hole transport material being selected from materials having hole transport ability, including at least one group selected from the group consisting of a carbazole group, a triphenylamine group, a fluorenyl group, and a thiophene group; and / or the thickness of the hole transport layer is 50 nm to 1800 nm, or the thickness of the hole transport layer is 50 nm to 3000 nm; and / or the anodic modification layer contains a metal oxide, and the metal oxide is MoO 3 , WoO 3 , V 2 O 5 The organic electroluminescent device according to any one of claims 1 to 6, wherein the organic electroluminescent device is selected from at least one of the following:

9. A method for improving hole injection ability into a hole transport layer, the method comprising the steps of: an anode modifying layer is disposed on a surface of an anode, and an organic interface layer and a hole transport layer are sequentially disposed on the anode modifying layer, the anode modifying layer comprising a metal oxide, the organic interface layer being an organic interface material, and the hole transport layer comprising a hole transport material; wherein the work function of the metal oxide is 6 eV to 7 eV; the HOMO energy level of the organic interfacial material is greater than the HOMO energy level of the hole transport material by 0.2 eV, 0.3 eV, 0.4 eV, 0.5 eV, 0.6 eV, or 0.7 eV, the thickness of the anodically modified layer is 5 nm to 100 nm, and the thickness of the organic interfacial layer is 1 nm to 20 nm.

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