An aromatic amine organic compound and application thereof in an organic electroluminescence device

Abstract

This invention discloses an aromatic amine organic compound and its application in organic electroluminescent devices, belonging to the field of semiconductor material technology. The structure of the organic compound provided by this invention is shown in general formula (1): The organic compound of this invention has excellent hole mobility and exciton blocking properties. When the aromatic amine organic compound of this invention is used to form the light-emitting auxiliary layer material of the organic electroluminescent device, the lifetime of the OLED device can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to an aromatic amine organic compound and its application in organic electroluminescent devices. Background Technology

[0002] Organic light-emitting diode (OLED) technology can be used to manufacture new display products and new lighting products, and it is expected to replace existing liquid crystal displays and fluorescent lighting, with a very wide range of applications. OLED light-emitting devices have a sandwich-like structure, including electrode material layers and organic functional materials sandwiched between different electrode material layers. Various organic functional materials are stacked together according to their intended use to form the OLED light-emitting device. As a current-carrying device, when a voltage is applied to the two electrodes of the OLED light-emitting device, and the positive and negative charges in the organic functional material layers are acted upon by an electric field, the positive and negative charges recombine in the light-emitting layer, thus generating OLED electroluminescence.

[0003] Currently, OLED display technology has been applied in smartphones, tablets, and other fields, and will further expand into large-screen applications such as televisions. However, compared with the requirements of actual product applications, the luminous efficiency, lifespan, and other performance characteristics of OLED devices still need further improvement. Research on improving the performance of OLED light-emitting devices includes: reducing the driving voltage of the device, increasing the luminous efficiency of the device, and increasing the lifespan of the device. To continuously improve the performance of OLED devices, it is necessary not only to innovate in OLED device structure and manufacturing processes, but also to continuously research and innovate OLED optoelectronic functional materials to create functional materials for higher-performance OLEDs.

[0004] Blue organic light-emitting diodes (OLEDs) have always been a weak point in the development of full-color OLEDs. To date, the efficiency and lifetime of blue light devices have been difficult to improve comprehensively. Therefore, improving the performance of these devices remains a crucial issue and challenge in this field. Currently, most blue light-emitting substrates used in the market are electron-biased. At low current densities, preferential hole injection alleviates the pressure on the hole transport side to some extent. However, as the current density increases, the amount of electron injection increases, causing the recombination region to shift towards the hole side, increasing the pressure on the hole side. To prevent excitons from being transferred to the hole side, the luminescent auxiliary layer material must effectively block excitons and efficiently transport holes to the luminescent layer. Currently, most luminescent auxiliary layer materials are traditional aromatic amine structures with carbazole or dibenzofuran groups as branching chains. The exciton resistance stability of these structures still cannot meet the requirements, and the hole mobility at high current densities needs to be improved to ensure carrier balance in the luminescent layer and prevent the recombination region from shifting towards the hole transport side due to insufficient holes, leading to reduced device efficiency and shorter lifetime. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, this invention provides an aromatic amine organic compound and its application in organic electroluminescent devices. The compound of this invention exhibits excellent hole mobility and exciton blocking properties, effectively improving the efficiency and extending the lifetime of OLED devices, especially with a significant improvement in device lifetime.

[0006] The technical solution of the present invention is as follows: an aromatic amine organic compound, the structure of which is shown in general formula (1):

[0007]

[0008] In general formula (1), R1 and R2 are respectively independently represented as substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted diphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted diphenylfluorenyl, substituted or unsubstituted spirofluorenyl, substituted or unsubstituted phenanthyl, substituted or unsubstituted indene, substituted or unsubstituted 5-30 member heteroaryl;

[0009] L1 represents a substituted or unsubstituted phenylene, a substituted or unsubstituted biphenylene, or a substituted or unsubstituted naphthylene;

[0010] L2 and L3 are respectively independently represented as a single bond, a substituted or unsubstituted phenylene, a substituted or unsubstituted biphenylene, or a substituted or unsubstituted naphthylene;

[0011] The R3 is represented by the structure shown in general formula (2);

[0012] The R4 is independently represented as phenyl, naphthyl, biphenyl, or the structure of general formula (2);

[0013] In general formula (2), X represents an oxygen atom or a sulfur atom;

[0014] The L4 is represented as a single bond, a substituted or unsubstituted phenylene, a substituted or unsubstituted biphenylene, or a substituted or unsubstituted naphthylene;

[0015] The R5-R 11 Represented independently as hydrogen atom, deuterium atom, and C1-C atom 10 Alkyl, substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted 5-30 heteroaryl groups, R5-R 11 Any two adjacent groups in the group can bond together to form a ring;

[0016] The substituents replacing the above groups may be selected from deuterium atoms, C1-C... 10 Alkyl, C6-C30 Aryl or 5-30 heteroaryl groups;

[0017] The heteroatom in the heteroaryl group is selected from one or more of oxygen, sulfur, or nitrogen atoms.

[0018] In the preferred embodiment, in general formula (1), R1 and R2 are independently represented as phenyl, naphthyl, dibenzofuranyl, dibenzothiophenyl, carbazoyl, diphenyl, triphenyl, and phenyl-substituted naphthyl, and the above groups can also be substituted by deuterium atoms;

[0019] L1, L2, and L3 are independently represented as phenylene, naphthylene, or diphenylene, respectively;

[0020] The R3 is represented by the structure shown in general formula (2);

[0021] The R4 is independently represented as phenyl, naphthyl, biphenyl, or the structure of general formula (2);

[0022] In general formula (2), X represents an oxygen atom or a sulfur atom;

[0023] The L4 is represented as a single bond, phenylene, naphthylene, or diphenylene;

[0024] The R5-R 11 Represented independently as hydrogen atom, deuterium atom, and C1-C atom 10 Alkyl, substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted 5-30 heteroaryl groups, R5-R 11 Any two adjacent groups in the group can bond together to form a ring;

[0025] The substituents replacing the above groups are selected from deuterium atoms, C1-C... 10 Alkyl, C6-C 30 Aryl, 5-30 heteroaryl;

[0026] The heteroatom in the heteroaryl group is selected from one or more of oxygen, sulfur, or nitrogen atoms.

[0027] In a preferred embodiment, the structure of the organic compound is shown in general formula (1-1):

[0028]

[0029] In general formula (1-1), L1, L2, L3, R1, R2, R4, X, R5-R 11 The meaning is the same as the limitation in the general formula (1) above.

[0030] In the preferred embodiment, in general formula (1-1), R1, R2, X, and R5-R 11The meaning is the same as the limitation mentioned above; L1, L2, and L3 are each independently represented as any one of the following structures: R4 can be represented independently as phenyl, naphthyl, or biphenyl.

[0031] In a preferred embodiment, the structure of the organic compound is shown in any one of general formulas (1-2) to (1-6):

[0032]

[0033] In general formulas (1-2) to (1-6), L2, L3, R1, R2, R4, X, R5-R 11 The meaning is the same as the limitation in the general formula (1) above.

[0034] In a preferred embodiment, the structure of the organic compound is shown in general formula (1-7):

[0035]

[0036] In general formulas (1-7), L1, L2, L3, L4, R1, R2, X, R5-R 11 The meaning is the same as the limitation in the general formula (1) above.

[0037] In a preferred embodiment, the structure of the organic compound is shown in general formulas (1-8):

[0038]

[0039] In general formulas (1-8), the meanings of R1, R2, L2, L3, and X are the same as those in general formula (1) above; R4 is independently represented as phenyl, naphthyl, or biphenyl.

[0040] In a preferred embodiment, L1, L2, L3, and L4 are each independently represented by the following structure:

[0041] Any one of them;

[0042] Each R4 is independently represented as shown in the following structure:

[0043]

[0044] The R1, R2, R5-R 11 Each can be represented independently as shown in the following structure:

[0045]

[0046]

[0047] In a preferred embodiment, the general formula (2) is represented by the following structure:

[0048]

[0049] The meanings of L4 and X are the same as those in the above text.

[0050] In a preferred embodiment, R1 and R2 are independently represented as one of the following: substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted diphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted phenanthyl, substituted or unsubstituted indene, substituted or unsubstituted furanyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted thiophene, substituted or unsubstituted benzothiophene, substituted or unsubstituted dibenzothiophene, substituted or unsubstituted piperonyl, substituted or unsubstituted carbazoyl, substituted or unsubstituted indolyl, 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene, and 1,4-benzodioxane.

[0051] The R5-R 11 Each of the following can be represented independently: hydrogen atom, deuterium atom, methyl, ethyl, tert-butyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted diphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted furanyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted thiopheneyl, substituted or unsubstituted benzothiopheneyl, substituted or unsubstituted dibenzothiopheneyl, substituted or unsubstituted phenanthyl, substituted or unsubstituted indolecycloyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted diphenylfluorenyl, substituted or unsubstituted carbazoyl, substituted or unsubstituted spirofluorenyl, substituted or unsubstituted indolocycloyl, 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene, and 1,4-benzodioxane.

[0052] In the preferred embodiment, in the general formula (1) It can be represented by any of the following structures:

[0053]

[0054] In a preferred embodiment, the aromatic amine organic compound has any one of the following structures:

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063] The present invention also provides an organic electroluminescent device, wherein at least one functional layer contains the aforementioned aromatic amine organic compound.

[0064] In a preferred embodiment, the organic electroluminescent device includes a hole transport region, a light-emitting layer, and an electron transport region, wherein the hole transport region comprises the aromatic amine organic compound.

[0065] Preferably, the hole transport region includes a hole injection layer, a hole transport layer, and a light-emitting auxiliary layer, wherein the light-emitting auxiliary layer contains the aromatic amine organic compound.

[0066] The present invention also provides that the display element comprises the aforementioned organic electroluminescent device.

[0067] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0068] (1) The unique functional group connection mode of the aromatic amine organic compounds of the present invention makes the compounds of the present invention have a better exciton blocking ability, so that the excitons are better localized in the light-emitting region, improving the utilization rate of excitons and thus improving the luminescence efficiency.

[0069] This invention application improves the connection between these functional groups, enabling the compounds of this application to have superior exciton blocking ability and hole mobility at high current density. When applied to devices, this improves device efficiency while exhibiting excellent device lifetime.

[0070] (2) Since the compound structure of this invention is stable, even when hole injection becomes stronger under high current density, it can still conduct holes to the light-emitting layer through different carrier conduction channels, thus ensuring the hole concentration under high current density and improving the luminous efficiency of the device.

[0071] (3) Because the structural characteristics of the organic compounds in this invention ensure that the material has a suitable glass transition temperature, it is also beneficial to reduce the vapor deposition temperature of the molecules. In other words, even if the molecular weight of the structure is relatively high, it can still ensure a low vapor deposition temperature. This excellent performance is not only beneficial to the thermal vapor deposition of the material, but also to the control of the thermal decomposition rate of the material. Attached Figure Description

[0072] Figure 1 This is a schematic diagram of the structure of an OLED device in which the materials listed in this invention are applied;

[0073] Among them, 1 is a transparent substrate layer, 2 is an anode layer, 3 is a hole injection layer, 4 is a hole transport layer, 5 is an auxiliary layer for the light-emitting layer, 6 is a light-emitting layer, 7 is a hole blocking layer, 8 is an electron transport layer, 9 is an electron injection layer, 10 is a cathode layer, and 11 is a capping layer.

[0074] Figure 2 The image shows the 1H NMR spectrum of compound 58.

[0075] Figure 3 This is the carbon NMR spectrum of compound 58. Detailed Implementation

[0076] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0077] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0078] In this invention, when a layer or element is referred to as being "above" another layer or substrate, the layer or element may be located directly above the other layer or substrate, or there may be intermediate layers. Furthermore, it will be understood that when a layer is referred to as being "between" two layers, the layer may be the only layer between the two layers, or there may be one or more intermediate layers. The same reference numerals throughout the drawings denote the same elements.

[0079] In this invention, the terms "upper," "lower," "top," and "bottom," used to describe electrodes, organic electroluminescent devices, and other structures, indicate orientation only in a specific state and do not imply that the structure can only exist in that orientation. Conversely, if the structure can be repositioned, such as by inverting it, the orientation of the structure changes accordingly. Specifically, in this invention, the "bottom" or "lower" side of the electrode refers to the side of the electrode closer to the substrate during fabrication, while the opposite side farther from the substrate is the "top" or "upper" side.

[0080] In this specification, the term "substitution" means that one or more hydrogen atoms on a specified atom or group are replaced by a specified group, provided that the normal valence of the specified atom is not exceeded under the existing conditions.

[0081] In this specification, hole characteristics refer to the characteristics that allow holes formed in the anode to be easily injected into and transported in the light-emitting layer when an electric field is applied, due to conductivity characteristics at the highest occupied molecular orbital (HOMO) level.

[0082] In this specification, electronic characteristics refer to the characteristics that allow electrons formed in the cathode to be readily injected into and transported in the light-emitting layer when an electric field is applied, and which are attributed to conductivity characteristics based on the lowest unoccupied molecular orbital (LUMO) level.

[0083] The organic electroluminescent device of the present invention can be a bottom-emitting organic electroluminescent device, a top-emitting organic electroluminescent device, or a multilayer organic electroluminescent device, and there is no specific limitation thereto.

[0084] In the organic electroluminescent device of this invention, any substrate commonly used in organic electroluminescent devices can also be used. Examples include transparent substrates, such as glass or transparent plastic substrates; opaque substrates, such as silicon substrates; and flexible polyimide (PI) film substrates. Different substrates have different mechanical strengths, thermal stability, transparency, surface smoothness, and water resistance. Their application varies depending on their properties. In this invention, a transparent substrate is preferred. There are no particular limitations on the thickness of the substrate.

[0085] anode

[0086] Preferably, the anode can be formed on the substrate. In this invention, the anode and cathode are opposite each other. The anode can be made of a conductor with a high work function to facilitate hole injection, and can be, for example, a metal such as nickel, platinum, copper, zinc, silver or alloys thereof; a metal oxide such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); a combination of metal and metal oxide, such as ZnO and Al or ITO and Ag; a conductive polymer such as poly(3-methylthiophene), poly(3,4-(ethylene-1,2-dioxy)thiophene), and polyaniline, but is not limited thereto. The thickness of the anode depends on the material used, typically 50-500 nm, preferably 70-300 nm, and more preferably 100-200 nm. In this invention, a combination of metal and metal oxide, ITO and Ag, is preferred.

[0087] cathode

[0088] The cathode can be made of a conductor with a low work function to facilitate electron injection, and can be, for example, a metal or alloy thereof, such as magnesium, calcium, sodium, potassium, titanium, indium, aluminum, silver, tin, and combinations thereof; multilayer materials, such as LiF / Al, Li2O / Al, and BaF2 / Ca, but not limited thereto. The thickness of the cathode depends on the material used, typically 10-50 nm, preferably 15-20 nm.

[0089] Light-emitting area

[0090] In this invention, the light-emitting region can be disposed between the anode and the cathode, and can include at least one host material and at least one guest material. Both the host and guest materials of the light-emitting region in the organic electroluminescent device of this invention can be light-emitting layer materials known in the prior art for organic electroluminescent devices. The host material can be, for example, a thiazole derivative, a benzimidazole derivative, a polydialkylfluorene derivative, or 4,4'-bis(9-carbazolyl)biphenyl (CBP). The host material can be a compound containing anthracene groups. The guest material can be, for example, a quinacridone, coumarin, rubrene, perylene and its derivatives, benzopyran derivatives, rhodamine derivatives, or aminostyrene derivatives.

[0091] In a preferred embodiment of the present invention, the luminescent region contains one or two host material compounds.

[0092] In a preferred embodiment of the present invention, the luminescent region contains two host material compounds, and the two host material compounds form an excitocomplex.

[0093] In a preferred embodiment of the present invention, the host material of the luminescent region is selected from one or more of the following compounds BH-1-BH-11:

[0094]

[0095]

[0096] In this invention, the luminescent region may contain phosphorescent or fluorescent guest materials to improve the fluorescence or phosphorescence properties of the organic electroluminescent device. Specific examples of phosphorescent guest materials include metal complexes of iridium, platinum, etc., while those commonly used in the art can be used for fluorescent guest materials. In a preferred embodiment of this invention, the guest material used in the luminescent film layer is selected from one of the following compounds: BD-1 to BD-10.

[0097]

[0098] In the light-emitting region of the present invention, the ratio of the host material to the guest material is 99:1-70:30, preferably 99:1-85:15 and more preferably 97:3-87:13, based on mass.

[0099] The thickness of the light-emitting region can be 10-50 nm, preferably 15-30 nm, but the thickness is not limited to this range.

[0100] Hole transport region

[0101] In the organic electroluminescent device of the present invention, a hole transport region is disposed between the anode and the light-emitting region, and includes a hole injection layer, a hole transport layer and a light-emitting auxiliary layer.

[0102] Hole injection layer

[0103] The hole injection material used in the hole injection layer (also known as the anode interface buffer layer) is a material capable of fully accepting holes from the anode at low voltages, and the highest occupied molecular orbital (HOMO) of the hole injection material is preferably a value between the work function of the anode material and the HOMO of the adjacent organic material layer. In a preferred embodiment of the invention, the hole injection layer is a mixed film layer of aromatic amine organic material and p-type doped material. For holes to be smoothly injected from the anode into the organic film layer, the HOMO energy level of the host organic material must possess certain characteristics with the p-type doped material to facilitate charge transfer states between the host and doped materials, achieving ohmic contact between the hole injection layer and the anode, thereby achieving efficient hole injection from the electrode to the hole injection layer. This characteristic is summarized as follows: the difference between the HOMO energy level of the host material and the LUMO energy level of the p-type doped material is ≤0.4 eV. Therefore, for hole-type host materials with different HOMO energy levels, different p-type doped materials need to be selected to match them in order to achieve ohmic contact at the interface and improve the hole injection effect.

[0104] Preferably, specific examples of the host organic material include: metalloporphyrins, oligothiophenes, aromatic amine organic materials, hexanitrile hexaazabenzanphenanthrene, quinacridone organic materials, perylene organic materials, anthraquinones, polyanilines, and polythiophene conductive polymers; but are not limited thereto. Preferably, the host organic material is an aromatic amine organic material.

[0105] Preferably, the p-type doped material is a charge-conducting compound selected from quinone derivatives or metal oxides, such as tungsten oxide and molybdenum oxide, but not limited thereto.

[0106] In a preferred embodiment of the present invention, the p-type doped material used is selected from any one of the following compounds HI1 to HI8:

[0107]

[0108] In one embodiment of the present invention, the ratio of the host organic material to the P-type doped material is 99:1-95:5, preferably 99:1-97:3, based on mass.

[0109] In a preferred embodiment of the present invention, the hole injection layer is a mixed film layer of aromatic amine compounds and p-type doped materials.

[0110] The thickness of the hole injection layer of the present invention can be 5-20 nm, preferably 8-15 nm, but the thickness is not limited to this range.

[0111] Hole transport layer

[0112] In the organic electroluminescent device of the present invention, a hole transport layer may be disposed above a hole injection layer. The hole transport material is a suitable material with high hole mobility, capable of accepting holes from the anode or hole injection layer and transporting the holes to the light-emitting layer. Specific examples include, but are not limited to, aromatic amine organic materials, conductive polymers, and block copolymers having both conjugated and non-conjugated portions. In a preferred embodiment, the hole transport layer comprises the same aromatic amine organic compound as the hole injection layer.

[0113] The thickness of the hole transport layer of the present invention can be 80, 100 or 200 nm, preferably 100-150 nm, but the thickness is not limited to this range.

[0114] Light-emitting layer auxiliary layer

[0115] In the organic electroluminescent device of the present invention, an auxiliary light-emitting layer can be disposed between the hole transport layer and the light-emitting layer, and particularly in contact with the light-emitting layer. By disposing of the auxiliary light-emitting layer in contact with the light-emitting layer, hole transfer at the interface between the light-emitting layer and the hole transport layer can be precisely controlled. In one embodiment of the present invention, the material of the auxiliary light-emitting layer is selected from the aromatic amine organic compounds of general formula (1). The thickness of the auxiliary light-emitting layer can be 5-20 nm, preferably 8-15 nm, but is not limited to this range.

[0116] Electronic transmission area

[0117] In the organic electroluminescent device of the present invention, the electron transport region is disposed between the light-emitting region and the cathode, and includes, but is not limited to, a hole blocking layer, an electron transport layer and an electron injection layer.

[0118] Electron injection layer

[0119] An electron injection layer may be disposed between the electron transport layer and the cathode. The electron injection layer material is typically preferably a material with a low work function, allowing electrons to be easily injected into the organic functional material layer. Preferably, the electron injection layer material is an N-type metal. As the electron injection layer material for the organic electroluminescent device of the present invention, electron injection layer materials known in the art for organic electroluminescent devices can be used, such as lithium; lithium salts, such as lithium 8-hydroxyquinoline, lithium fluoride, lithium carbonate, or lithium azide; or cesium salts, such as cesium fluoride, cesium carbonate, or cesium azide. The thickness of the electron injection layer of the present invention may be 0.1-5 nm, preferably 0.5-3 nm, and more preferably 0.8-1.5 nm, but the thickness is not limited to this range.

[0120] Electron transport layer

[0121] An electron transport layer may be disposed above the light-emitting film layer or (if present) a hole-blocking layer. The electron transport layer material is one that readily receives electrons from the cathode and transfers the received electrons to the light-emitting layer. A material with high electron mobility is preferred. As the electron transport layer of the organic electroluminescent device of the present invention, electron transport layer materials known in the prior art for organic electroluminescent devices can be used, such as metal complexes of hydroxyquinoline derivatives represented by Alq3, BAlq and LiQ, various rare earth metal complexes, triazole derivatives, triazine derivatives such as 2,4-bis(9,9-dimethyl-9H-fluoren-2-yl)-6-(naphth-2-yl)-1,3,5-triazine (CAS No.: 1459162-51-6), imidazole derivatives such as 2-(4-(9,10-bis(naphth-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole (CAS No.: 561064-11-7, commonly known as LG201), oxadiazole derivatives, etc.

[0122] In a preferred embodiment of the invention, the electron transport layer comprises any one of the following compounds:

[0123]

[0124]

[0125] In a more preferred embodiment of the invention, the electron transport layer comprises any one of the following compounds:

[0126] (E1), (E5), (E12), (E16) or (E23).

[0127] In a preferred embodiment of the invention, in addition to the compounds shown in (E1) to (E31), the electron transport layer also includes other compounds conventionally used in electron transport layers, such as Alq3, LiQ, preferably LiQ. In a more preferred embodiment of the invention, the electron transport layer is composed of one of the compounds shown in (E1) to (E31) and another of the compounds conventionally used in electron transport layers (preferably LiQ).

[0128] The hole injection and transport rates of the hole transport region containing the aromatic amine compounds of the present invention can be well matched with the electron injection and transport rates. Preferably, the hole injection and transport rates of the hole transport region containing the aromatic amine compounds of the present invention can be better matched with the electron injection and transport rates of the electron transport region containing the nitrogen heterocyclic compounds of general formula (4).

[0129] Therefore, in a particular embodiment of the present invention, using an electron transport region consisting of one or more nitrogen heterocyclic compounds of general formula (4) or composed thereof, in combination with a hole transport region consisting of an aromatic amine compound of the present invention, achieves relatively better technical results.

[0130] The thickness of the electron transport layer of the present invention can be 10-80 nm, preferably 20-60 nm, and more preferably 25-45 nm, but the thickness is not limited to this range.

[0131] Cover layer

[0132] To improve the light extraction efficiency of organic electroluminescent devices, a light extraction layer (CPL layer, also known as a capping layer) can be added to the cathode of the device. According to the principles of optical absorption and refraction, the CPL capping layer material should have a higher refractive index and a lower absorption coefficient. Any material known in the art can be used as the CPL layer material, such as Alq3 or N4,N4'-diphenyl-N4,N4'-di(9-phenyl-3-carbazolyl)biphenyl-4,4'-diamine. The thickness of the CPL capping layer is typically 5-300 nm, preferably 20-100 nm, and more preferably 40-80 nm.

[0133] The organic electroluminescent device of the present invention may further include an encapsulation structure. The encapsulation structure may be a protective structure preventing external 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 or metal can; or a thin film covering the entire surface of the organic layer.

[0134] The organic electroluminescent device according to an embodiment of the present invention is described below.

[0135] In the accompanying drawings, the thicknesses of layers, films, substrates, regions, etc., are enlarged for clarity. Throughout the specification, the same reference numerals denote the same elements. It should be understood that when an element such as a layer, film, region, or substrate is referred to as "on" another element, it may be directly on the other element or there may be intercalating elements. In contrast, when an element is referred to as "directly on" another element, there are no intercalating elements.

[0136] This invention also relates to a method for fabricating an organic electroluminescent device, comprising sequentially laminating an anode, a hole injection layer, a hole transport layer, a light-emitting auxiliary layer, an organic film layer, an electron transport layer, an electron injection layer, and a cathode, and optionally a capping layer, on a substrate. In this regard, methods such as vacuum deposition, vacuum evaporation, spin coating, casting, LB method, inkjet printing, laser printing, or LITI can be used, but are not limited thereto. In this invention, vacuum evaporation is preferably used to form the various layers. Those skilled in the art can conventionally select the various process conditions in the vacuum evaporation method according to actual needs.

[0137] In addition, it should be noted that the materials used to form each layer described in this invention can be used as a single layer by forming a film on their own, or they can be used as a single layer by mixing with other materials to form a film. They can also be a stacked structure between layers that are formed on their own, a stacked structure between layers that are formed by mixing, or a stacked structure between layers that are formed on their own and layers that are formed by mixing.

[0138] Preparation Examples

[0139] Synthesis of intermediate C-1:

[0140]

[0141] In a three-necked flask, 10 mmol of starting material A-1 and 15 mmol of starting material B-1 were dissolved in 25 mL of tetrahydrofuran (THF), followed by the addition of 0.1 mmol of Pd(PPh3)4 and 15 mL of a 3 mol / L K2CO3 aqueous solution. The mixture was heated under nitrogen protection and refluxed for 12 hours. The reaction was monitored using thin-layer chromatography until the reaction mixture was completely cooled to room temperature. The reaction mixture was filtered through a diatomaceous earth filter, washed with chloroform, and the resulting filtrate was rotary evaporated. The residue was purified by column chromatography using hexane / toluene as the eluent to give intermediate C-1. LC-MS: Measured value: 475.18 ([M+H) + Theoretical value: 474.06.

[0142] Intermediates C-2 to C-7 were prepared using a method similar to that used for the synthesis of intermediate C-1 in the examples, with raw material A and raw material B used as shown in Table 1 below:

[0143] Table 1

[0144]

[0145] Synthesis of intermediate C-8:

[0146]

[0147] Step 1: Under nitrogen protection, add 14 mmol of starting material E-1, 18 mmol of starting material D-1, 48 mL of toluene, 24 mL of ethanol, 12 mL of water, and 36 mmol of potassium carbonate to the reaction flask. After the addition is complete, stir and heat to 50-60℃. Quickly add 0.3 mmol of tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) and 25 mmol of tetrabutylammonium bromide (TBAB). After the addition is complete, continue heating to 70-75℃ and reflux for 17 h. After the reaction is complete, cool to room temperature, extract with dichloromethane, wash the organic phase with water until neutral, dry, filter, and concentrate. Obtain intermediate F-1. LC-MS: Measured value: 316.89 ([M+H) + Theoretical value: 315.97.

[0148] Step 2: Under nitrogen protection, 25 mmol of starting material A-2 and 29 mmol of intermediate F-1 were added to a three-necked flask and dissolved in 25 mL of tetrahydrofuran (THF). Then, 0.1 mmol of Pd(PPh3)4 and 15 mL of 3 mol / L K2CO3 aqueous solution were added. The mixture was heated to reflux for 13 hours under nitrogen protection. The reaction was monitored using thin-layer chromatography until it was completely cooled to room temperature. The reaction mixture was filtered through a diatomaceous earth filter, washed with chloroform, and the filtrate was rotary evaporated. The residue was purified by column chromatography using hexane / toluene as the eluent to give intermediate C-8. LC-MS: Measured value: 481.25 ([M+H) + Theoretical value: 480.13.

[0149] Intermediates C-9 to C-12 were prepared using a method similar to that used in the synthesis of intermediate C-8 in the examples. The raw materials A, D, and E used are shown in Table 2 below:

[0150] Table 2

[0151]

[0152]

[0153] Synthesis of intermediate C-13:

[0154]

[0155] Step 1: Under nitrogen protection, 30 mmol of starting material A-8 and 38 mmol of starting material B-2 were added to a three-necked flask and dissolved in 30 mL of tetrahydrofuran (THF). Then, 0.1 mmol of Pd(PPh3)4 and 15 mL of 3 mol / L K2CO3 aqueous solution were added, and the mixture was heated to reflux for 12 hours. The reaction was monitored using thin-layer chromatography until the reaction was completely cooled to room temperature. The reaction mixture was filtered through a diatomaceous earth filter, washed with chloroform, and the filtrate was rotary evaporated. The residue was purified by column chromatography using hexane / toluene as the eluent to give intermediate G-1. LC-MS: Measured value: 355.21 ([M+H) + Theoretical value: 354.08.

[0156] Step 2: Under nitrogen protection, 20 mmol of intermediate G-1, 100 mmol of copper iodide, 300 mmol of potassium iodide, and 50 ml of DMI were added to a three-necked flask. The mixture was stirred at 140–150 °C for 12 hours. Tetrahydrofuran and saturated brine were added, the aqueous layer was removed, and the extracted organic layer was concentrated under reduced pressure. The reaction was monitored by HPLC to ensure complete reaction, yielding intermediate H-1. LC-MS: Measured value: 447.13 ([M+H)) +Theoretical value: 446.02.

[0157] Step 3: Under nitrogen protection, 30 mmol of starting material A-9 and 38 mmol of intermediate H-1 were added to a three-necked flask and dissolved in 30 mL of tetrahydrofuran (THF). Then, 0.1 mmol of Pd(PPh3)4 and 15 mL of 3 mol / L K2CO3 aqueous solution were added, and the mixture was heated under reflux for 15 hours. The reaction was monitored using thin-layer chromatography until the reaction was completely cooled to room temperature. The reaction mixture was filtered through a diatomaceous earth filter, washed with chloroform, and the filtrate was rotary evaporated. The residue was purified by column chromatography using hexane / toluene as the eluent to give intermediate C-13. LC-MS: Measured value: 551.17 ([M+H) + Theoretical value: 550.09.

[0158] Synthesis of intermediate C-14:

[0159]

[0160] Step 1: Under nitrogen protection, 32 mmol of starting material A-8 and 41 mmol of starting material B-3 were added to a three-necked flask and dissolved in 34 mL of tetrahydrofuran (THF). Then, 0.1 mmol of Pd(PPh3)4 and 20 mL of 3 mol / L K2CO3 aqueous solution were added, and the mixture was heated under reflux for 12 hours. The reaction was monitored using thin-layer chromatography until the reaction was completely cooled to room temperature. The reaction mixture was filtered through a diatomaceous earth filter, washed with chloroform, and the filtrate was rotary evaporated. The residue was purified by column chromatography using hexane / toluene as the eluent to give intermediate G-2. LC-MS: Measured value: 355.16 ([M+H) + Theoretical value: 354.08.

[0161] Step 2: Under nitrogen protection, 22 mmol of intermediate G-2, 100 mmol of copper iodide, 300 mmol of potassium iodide, and 50 ml of DMI were added to a three-necked flask. The mixture was stirred at 140–150 °C for 12 hours. Tetrahydrofuran and saturated brine were added, the aqueous layer was removed, and the extracted organic layer was concentrated under reduced pressure. The reaction was monitored by HPLC to ensure complete reaction, yielding intermediate H-2. LC-MS: Measured value: 447.11 ([M+H)) + Theoretical value: 446.02.

[0162] Step 3: Under nitrogen protection, 31 mmol of starting material A-9 and 40 mmol of intermediate H-2 were added to a three-necked flask, dissolved in 30 mL of tetrahydrofuran (THF), followed by the addition of 0.1 mmol of Pd(PPh3)4 and 18 mL of 3 mol / L K2CO3 aqueous solution. The mixture was heated to reflux for 15 hours. The reaction was monitored using thin-layer chromatography until completely cooled to room temperature. The reaction mixture was filtered through a diatomaceous earth filter, washed with chloroform, and the filtrate was rotary evaporated. The residue was purified by column chromatography using hexane / toluene as the eluent to give intermediate C-14. LC-MS: Measured value: 551.12 ([M+H) + Theoretical value: 550.09.

[0163] Synthesis of Compound 1:

[0164]

[0165] Under nitrogen protection, in a dry three-necked flask, 24 mmol of intermediate C-1, 32 mmol of starting material K-1, 21 mmol of sodium tert-butoxide, 0.17 mmol of Pd2(dba)3, 0.1 mol of tri-tert-butylphosphine, and 200 mL of toluene were added. After the addition was complete, the mixture was heated to reflux and reacted for 5 hours. After the reaction was completed by TLC monitoring, it was naturally cooled to room temperature, filtered, and the filtrate was rotary evaporated until no fraction remained. The filtrate was then passed through a neutral silica gel column to give compound 1. Elemental analysis and structure (molecular formula C...) 58 H 39 NO): Theoretical values: C, 90.95; H, 5.13; N, 1.83; Measured values: C, 90.85; H, 5.12; N, 1.95. LC-MS: Measured value: 766.32 ([M+H]) + Theoretical value: 765.30.

[0166] The following compounds were prepared using the same method as compound 1, and the starting materials are shown in Table 4 below:

[0167] Table 4

[0168]

[0169]

[0170]

[0171] Device Comparison Example 1

[0172] The specific preparation process is as follows:

[0173] like Figure 1As shown, the substrate layer 1 (glass) is used to wash the anode layer 2 (Ag (100nm)) by sequentially performing alkaline washing, pure water washing, drying, and then ultraviolet-ozone washing to remove organic residues from the surface of the anode layer. After the above washing, a hole injection layer 3 (HT1 and HI1 with a mass ratio of 97:3) is deposited on the anode layer 2 using a vacuum evaporation apparatus, with a thickness of 10nm. Next, a hole transport layer 4 (HT1 with a thickness of 117nm) is deposited. Then, a hole-transport layer 5 (EB-1 with a thickness of 10nm) is deposited. After the above hole-transport layer deposition, the OLED light-emitting layer 6 is fabricated. Its structure includes BH-1 as the host material and BD-1 as the dopant material, with a doping ratio of 3% by weight, and a thickness of 20nm. After the light-emitting layer 6, HB1 is deposited with a thickness of 8nm as the hole blocking layer 7. On top of the hole-blocking layer 7, E1 and Liq are further deposited by vacuum evaporation, with a mass ratio of E1 to Liq of 1:1. The vacuum-deposited film thickness of this material is 30 nm, and this layer serves as the electron transport layer 8. On the electron transport layer 8, a LiF layer with a thickness of 1 nm is formed by vacuum evaporation, and this layer serves as the electron injection layer 9. On the electron injection layer 9, a Mg:Ag electrode layer with a thickness of 16 nm is formed by vacuum evaporation, with a mass ratio of Mg to Ag of 1:9, and this layer serves as the cathode layer 10. On the cathode layer 10, a 65 nm thick CP-1 layer is vacuum-deposited as the CPL layer 11.

[0174] Device Comparison Examples 2-5

[0175] The method was carried out according to the device comparison example 1, except that the organic materials in the auxiliary layer of the light-emitting layer were replaced with the organic materials shown in Table 5.

[0176] Device Examples 1-21

[0177] The method was carried out according to the device comparison example 1, except that the organic material of the light-emitting layer auxiliary layer was replaced with the organic material shown in Table 5.

[0178]

[0179] After completing the OLED light-emitting device as described above, the anode and cathode are connected using a known driving circuit, and the current efficiency, emission spectrum, and lifetime of the device are measured.

[0180] Table 5

[0181]

[0182]

[0183] Taking Example 1 as an example in the table above, "HI1:HT1=3:9710nm" in the second column indicates that the materials used in the hole injection layer are compound HT1 and p-type doped material HI1, 3:97 refers to the weight ratio of p-type doped material HI1 to compound HT1 of 3:97, and 10nm represents the thickness of the layer; "110nm" in the fourth column indicates that the material used is compound 1, and the thickness of the layer is 10nm. The meanings in the other tables can be deduced similarly.

[0184] After fabricating the OLED light-emitting device as described above, the cathode and anode were connected using a known driving circuit, and various performance parameters of the device were measured. The performance measurement results of the devices in Examples 1-21 and Comparative Examples 1-4 are shown in Table 6.

[0185] Table 6

[0186]

[0187] Note: Voltage, current efficiency, and color coordinates were measured using an IVL (current-voltage-luminance) testing system (Suzhou Fushida Scientific Instruments Co., Ltd.), with a current density of 10 mA / cm² during testing. 2 The lifetime testing system is the EAS-62C OLED device lifetime tester from System Technology Inc. of Japan; LT95 refers to the time it takes for the device brightness to decay to 95% at a specific brightness level.

[0188] As can be seen from the device data results in Table 6, in Device Examples 1-21, compared with Device Comparative Examples 1-5, using the aromatic amine compounds of the present invention as the light-emitting auxiliary layer material effectively improves the device efficiency and lifetime due to their high carrier transport rate and excellent exciton blocking ability. In particular, the device efficiency is unexpectedly significantly improved.

Claims

1. An aromatic amine organic compound, characterized in that, The structure of this organic compound is shown in general formula (1): General formula (1) General formula (2) In general formula (1), R1 and R2 are respectively independently represented as one of substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted diphenyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted benzothiophenyl, substituted or unsubstituted dibenzothiophenyl, and substituted or unsubstituted carbazoyl. L1 represents a substituted or unsubstituted phenylene, a substituted or unsubstituted biphenylene, or a substituted or unsubstituted naphthylene; L2 and L3 are respectively independently represented as a single bond, a substituted or unsubstituted phenylene, a substituted or unsubstituted biphenylene, or a substituted or unsubstituted naphthylene; The R3 is represented by the structure shown in general formula (2); The R4 is independently represented as phenyl, naphthyl, biphenyl or the structure of general formula (2); In general formula (2), X represents an oxygen atom or a sulfur atom; The L4 is represented as a single bond, a substituted or unsubstituted phenylene, a substituted or unsubstituted biphenylene, or a substituted or unsubstituted naphthylene; The R5-R 11 Each can be represented independently as a hydrogen atom, or as a substituted or unsubstituted phenyl group; The substituents that replace the above groups may be selected from phenyl groups.

2. The aromatic amine organic compound according to claim 1, characterized in that, In general formula (1), R1 and R2 are independently represented as phenyl, naphthyl, dibenzofuranyl, dibenzothiophenyl, carbazoyl, diphenyl, triphenyl, and phenyl-substituted naphthyl, respectively; L1, L2, and L3 are independently represented as phenylene, naphthylene, or diphenylene, respectively; The R3 is represented by the structure shown in general formula (2); The R4 is independently represented as phenyl, naphthyl, biphenyl or the structure of general formula (2); In general formula (2), X represents an oxygen atom or a sulfur atom; The L4 is represented as a single bond, phenylene, naphthylene, or diphenylene; The R5-R 11 Each can be represented independently as a hydrogen atom, or as a substituted or unsubstituted phenyl group; The substituents that replace the above groups are selected from phenyl groups.

3. The aromatic amine organic compound according to claim 1, characterized in that, The structure of this organic compound is shown in general formula (1-1): General formula (1-1) In general formula (1-1), L1, L2, L3, R1, R2, R4, X, R5-R 11 The meaning is the same as that defined in claim 1.

4. The aromatic amine organic compound according to claim 1, characterized in that, The structure of the organic compound is shown in any one of general formulas (1-2) to (1-6): General formula (1-2) General formula (1-3) General formula (1-4) General formula (1-5) General formula (1-6) In general formulas (1-2) to (1-6), L2, L3, R1, R2, R4, X, R5-R 11 The meaning is the same as that defined in claim 1.

5. The aromatic amine organic compound according to claim 1, characterized in that, The structure of this organic compound is shown in general formula (1-7): General formula (1-7) In general formulas (1-7), L1, L2, L3, L4, R1, R2, X, R5-R 11 The meaning is the same as that defined in claim 1.

6. The aromatic amine organic compound according to claim 1, characterized in that, L1, L2, and L3 are each independently represented by the following structures: , , , , , , , , or Any one of them; The L4 is represented by the following structure: , , , , or Any one of them; Each R4 is independently represented as shown in the following structure: 、 、 、 、 、 、 、 、 ； R1 and R2 are independently represented as shown in the following structures: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , or .

7. An aromatic amine organic compound, characterized in that, The organic compound has a specific structure that is any one of the following: (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) (43) (44) (45) (46) (47) (48) (49) (50) (51) (52) (53) (54) (55) (56) (57) (58) (59) (60) (61) (62) (63) (64) (65) (66) (67) (68) (69) (70) (71) (72) (73) (74) (75) (76) (77) (78) (79) (80) (81) (82) (83) (84) (85) (86) (87) (88) (89) (90) (91) (92) (93) (94) (95) (96) (97) (98) (99) (100) (101) (102) (103) (104) (105) (106) (107) (108) (109) (110) (111) (112) (113) (114) (115) (116) (117) (118) (119) (120) (121) (122) (123) (124) (125) (126) (127) (128) (129) (130) (131) (132) (133) (134) (135) (136) (137) (138) (139) (140) (141) (142) (143) (144) (145) (146) (147) (148) (149) (150) (151) (152) (153) (154) (155) (156) (157) (158) (159) (160) (161) (162) (163) (164) (165) (166) (167) (168) (169) (170) (171) (172) (173) (174) (175) (176) (177) (178) (179) (180) (181) (182) (183) (184) (185) (186) (187) (188) (189) (190) (191) (192) (193) (194) (195) (196) (197) (198) (199) (200) 。 8. An aromatic amine organic compound, characterized in that, The structure of this organic compound is shown in general formula (1): General formula (1) General formula (2) In general formula (1), R1 and R2 are respectively independently represented as one of substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted diphenyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted benzothiophenyl, substituted or unsubstituted dibenzothiophenyl, and substituted or unsubstituted carbazoyl. L1 represents a substituted or unsubstituted phenylene, a substituted or unsubstituted biphenylene, or a substituted or unsubstituted naphthylene; L2 and L3 are respectively independently represented as a single bond, a substituted or unsubstituted phenylene, a substituted or unsubstituted biphenylene, or a substituted or unsubstituted naphthylene; The R3 is represented by the structure shown in general formula (2); The R4 is independently represented as phenyl, naphthyl, biphenyl or the structure of general formula (2); The general formula (2) is represented by the following structure: 、 、 、 、 ； X represents an oxygen atom or a sulfur atom; The L4 is represented as a single bond, a substituted or unsubstituted phenylene, a substituted or unsubstituted biphenylene, or a substituted or unsubstituted naphthylene; The substituents that replace the above groups may be selected from phenyl groups.

9. An organic electroluminescent device, characterized in that, At least one functional layer contains an aromatic amine organic compound as described in any one of claims 1-8.

10. The organic electroluminescent device according to claim 9, comprising a hole transport region, a light-emitting layer, and an electron transport region, characterized in that, The hole transport region comprises any one of the aromatic amine organic compounds according to claims 1-8.

11. The organic electroluminescent device according to claim 10, wherein the hole transport region comprises a hole injection layer, a hole transport layer, and an auxiliary light-emitting layer, characterized in that, The auxiliary layer of the light-emitting layer comprises any one of the aromatic amine organic compounds according to claims 1-8.

12. A display element, characterized in that, The display element comprises the organic electroluminescent device according to any one of claims 9-11.

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