A bisarylamine organic compound and an organic electroluminescent device prepared therefrom

Abstract

The present invention discloses a bisarylamine organic compound and an organic electroluminescent device prepared therefrom, belonging to the technical field of semiconductor materials; the structure of the compound is shown in general formula (1): The organic compound of the present invention has excellent hole transport ability and thermal stability. When using the bisarylamine organic compound of the present invention to form the hole transport material of the organic electroluminescent device, the effects of improving the device efficiency and extending the lifetime can be simultaneously shown, especially extending the high-temperature lifetime of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials, and more particularly to a bisarylamine organic compound and an organic electroluminescent device prepared therefrom. Background Art

[0002] In an organic electroluminescent device (OLED), carriers (holes and electrons) are injected into the device from two electrodes of the device respectively under the drive of an electric field, and meet and recombine to emit light in the organic light-emitting layer. For a high-performance organic electroluminescent device, various organic functional materials are required to have good optoelectronic properties. For example, as a charge transport material, it is required to have good carrier mobility. The injection and transport characteristics of the hole injection layer material and the hole transport layer material used in the existing organic electroluminescent devices are relatively weak, and the hole injection and transport rates do not match the electron injection and transport rates, resulting in a large offset of the recombination region, which is not conducive to the stability of the device. In addition, a reasonable energy level matching of the hole injection layer material and the hole transport layer material is an important factor for improving the device efficiency and device life. Therefore, how to adjust the balance between holes and electrons and adjust the recombination region has always been an important topic in this field.

[0003] Blue organic electroluminescent devices have always been the weak link in the development of full-color OLEDs. So far, the performance such as the efficiency and life of blue light devices has been difficult to be comprehensively improved. Therefore, how to improve the performance of such devices is still a crucial problem and challenge faced in this field. Most of the blue light host materials used in the current market are electron-rich hosts. Therefore, in order to adjust the carrier balance of the light-emitting layer, a hole transport material with excellent hole transport performance is required. The better the hole injection and transport, the recombination region will shift away from the electron blocking layer side, thus away from the interface light emission, improving the device performance and increasing the life. Therefore, the hole transport region material is required to have high hole injectability, high hole mobility, high electron blocking property and high electron weather resistance.

[0004] It is well known in this field that in a high-temperature environment, due to the more obvious difference between the electron mobility and the hole mobility, the blue light device shows electron-rich and hole-deficient under high-temperature conditions, and the device life is poor. In order to improve the high-temperature life of the blue light device, it is necessary to improve the mobility of the hole transport material, especially the mobility under high-temperature conditions. Summary of the Invention

[0005] In view of the above problems existing in the prior art, the applicant of the present invention provides a bisarylamine organic compound and an organic electroluminescent device prepared therefrom. The organic compound of the present invention has excellent hole transport ability and thermal stability. When using the bisarylamine organic compound of the present invention to form the hole transport material of the organic electroluminescent device, the effects of improving the device efficiency and extending the life can be simultaneously shown, especially extending the high-temperature life of the device.

[0006] The technical solution of the present invention is as follows:

[0007] A bisarylamine organic compound, the structure of the compound is shown in the general formula (1):

[0008]

[0009] In the general formula (1), a and c each independently represent the number 0 or 1, and a + c = 1;

[0010] R1-R4 each independently represent a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted furyl group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted benzofuryl group, a substituted or unsubstituted benzothienyl group, a substituted or unsubstituted dibenzofuryl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted piperonyl group, or a substituted or unsubstituted indenyl group, and the connection mode of R1 and R2 with the main structure in the general formula (1) is single bond substitution or formation of a fused ring;

[0011] When R3 and R4 each independently represent a substituted or unsubstituted thienyl group or a substituted or unsubstituted furyl group, the connection mode of R3 and R4 with the main structure in the general formula (1) is single bond substitution or formation of a fused ring;

[0012] Ar represents a structure shown in the general formula (2) or the general formula (3);

[0013]

[0014] m, n, p, and q each represent the number 0, 1, or 2;

[0015] When p and m both represent 0 and n and q both represent 1, R2 and R3 do not simultaneously represent a phenyl group;

[0016] When m, n, p, and q all represent the number 1, R1-R4 do not simultaneously represent a phenyl group;

[0017] When Ar represents a structure shown in the general formula (3), m, n, p, and q do not simultaneously represent 0;

[0018] Ra and Rb each independently represent a hydrogen atom, a deuterium atom, a methyl group, an ethyl group, or a tert-butyl group;

[0019] The substituents for the substituting groups are a deuterium atom, a methyl group, an ethyl group, a tert-butyl group, an adamantyl group, a phenyl group, a naphthyl group, or a biphenyl group.

[0020] In a preferred embodiment, the structure of the compound is shown in the general formula (1-1):

[0021]

[0022] The meanings of R1, R2, Ar, m, n, a, and c are the same as those defined in the above text.

[0023] In a preferred embodiment, the structure of the compound is shown by the general formula (1-2):

[0024]

[0025] The meanings of R2-R4, Ar, p, q, n, a, and c are the same as those defined in the above text.

[0026] In a preferred embodiment, the structure of the compound is shown by the general formula (1-3):

[0027]

[0028] The meanings of R1-R3, Ar, q, m, n, a, and c are the same as those defined in the above text.

[0029] Further preferably, R1-R4 are each independently represented by one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, and a substituted or unsubstituted biphenyl group; Ra and Rb are each independently represented by a hydrogen atom or a deuterium atom.

[0030] More preferably, in the general formula (1) are represented by different groups.

[0031] Further preferably, the structure of the compound is shown by the general formula (1-4):

[0032]

[0033] In the general formula (1-4), the dashed line represents being connected by a single bond or not connected;

[0034] R1-R4 are each independently represented by one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted furyl group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted benzofuryl group, a substituted or unsubstituted benzothienyl group, a substituted or unsubstituted dibenzofuryl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted piperonyl group, and a substituted or unsubstituted indenyl group, and the connection mode of R1 and R2 to the main structure in the general formula (1) is single-bond substitution or formation of a fused ring;

[0035] When R3 and R4 are each independently represented by a substituted or unsubstituted thienyl group or a substituted or unsubstituted furyl group, the connection mode of R3 and R4 to the main structure in the general formula (1) is single-bond substitution or formation of a fused ring;

[0036] m, n, p, and q are respectively represented by the numbers 0, 1, or 2;

[0037] When p and m are both represented by 0 and n and q are both represented by 1, R2 and R3 are not both represented by phenyl;

[0038] When m, n, p, and q are all represented by the number 1, R1 - R4 are not all represented by phenyl;

[0039] When the dashed line is represented as not connected, m, n, p, and q are not all represented by 0;

[0040] Ra and Rb are each independently represented by a hydrogen atom, a deuterium atom, a methyl group, an ethyl group, or a tert - butyl group;

[0041] The substituents for the substituent groups are a deuterium atom, a methyl group, an ethyl group, a tert - butyl group, an adamantyl group, a phenyl group, a naphthyl group, or a biphenyl group.

[0042] More preferably, in the general formula (1 - 4) are represented by different groups.

[0043] Further preferably, Ar is represented by the structure shown in the general formula (2), and m, n, p, and q are all represented by the number 0.

[0044] In a preferred embodiment, the specific structure of the compound is any one of the following structures:

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062] An organic electroluminescent device, which sequentially includes an anode, a hole transport region, a light-emitting region, an electron transport region and a cathode, wherein the hole transport region contains the bisarylamine organic compound.

[0063] Preferably, the hole transport region includes a hole injection layer, a hole transport layer and an electron blocking layer, and the hole transport layer and the hole injection layer contain the bisarylamine organic compound.

[0064] More preferably, the hole transport layer contains the bisarylamine organic compound, and the hole injection layer is composed of the bisarylamine organic compound and other conventional P-type doping materials for the hole injection layer.

[0065] More preferably, the electron transport region contains the azacyclic compound represented by the general formula (4):

[0066]

[0067] Wherein, Ar5, Ar6, and Ar7 are each independently selected from a substituted or unsubstituted C6-C 30 aryl, a substituted or unsubstituted C2-C containing one or more heteroatoms 30 heterocyclic group;

[0068] L3 represents a single bond, a substituted or unsubstituted C6-C 30 arylene, a substituted or unsubstituted C2-C containing one or more heteroatoms 30 heteroarylene; X1, X2, and X3 each independently represent N or CH, and at least one of X1, X2, and X3 represents N;

[0069] Each of the heteroatoms is independently selected from N, O or S;

[0070] The substituents for the substituents are one or more of a deuterium atom, a phenyl group, a naphthyl group, a biphenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a pyridyl group or a pyrimidinyl group.

[0071] The beneficial technical effect of the present invention is as follows:

[0072] The compounds of the present invention application have the following structural characteristics: the diarylamine structure uses a fluorenyl group and a phenyl group as bridging groups. One arylamine is connected to one benzene ring side of the fluorenyl group through a phenyl group, and this arylamine and the fluorenyl group must be in the para position of the phenyl group. The other arylamine is directly connected to the other benzene ring side of the fluorenyl group through a single bond. This connection method endows the compounds of the present invention application with the following advantages:

[0073] (1) This connection method endows the compounds of the present invention application with excellent hole mobility. The improvement of hole mobility enables more holes to be injected into the host. The increase in the exciton concentration in the host enhances the TTA generation efficiency and exciton utilization rate, thereby improving the device efficiency.

[0074] (2) This connection method endows the compounds of the present invention application with appropriate energy levels. The reasonable energy level matching enables the injection and conduction of carriers to be more smooth, prevents accumulation at the interface, is conducive to the improvement of interface stability, and excellent interface stability is beneficial to the improvement of device lifetime.

[0075] (3) This connection method is conducive to the improvement of the glass transition temperature of the molecule and is also conducive to the reduction of the evaporation temperature of the molecule. That is to say, even if the molecular weight of the molecule is relatively high, it can ensure a relatively low evaporation temperature. This excellent performance is not only conducive to the thermal evaporation of the material and the control of the thermal decomposition rate of the material, thereby improving the stability of the material in device applications.

[0076] Moreover, for the diarylamine molecular structural formula with the characteristics of the present invention, the optimization of the ligands connected to the diarylamine is beneficial to further improve the performance of the material. For example, selecting some groups or group derivatives with strong planarity or large structural radii such as biphenyl group, benzofuran group, benzothiophene group or naphthalene group (homogeneous groups containing fused ring structures or substituted structures) is more conducive to improving the stability and mobility of the material, and is also conducive to the precise regulation of the HOMO energy level of the material, thereby obtaining good device application effects of the material.

[0077] The organic functional materials that make up an OLED device not only include hole injection and conduction materials, but also electron injection and conduction materials and light-emitting layer materials. Good device application effects require good carrier balance as a guarantee. Therefore, in order to obtain the best device application effects, the diamine materials that match the characteristic structure of the present invention also need to be paired with specific electron-type materials. Based on the in-depth research of the present inventors, the electron-type materials are preferably materials with a pyridine ring structure characteristic, such as triazine materials, pyridine materials, pyrazine materials, etc. or derivatives containing these characteristic groups. The diamine organic compounds of the present invention, when combined with pyridine ring-based electron transport materials, make it easy for electrons and holes to obtain the best balance state, and have excellent lifetime while having high efficiency, especially easy to obtain good high-temperature lifetime effects of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 is a cross-sectional view of the organic electroluminescent device of the present invention;

[0079] In the figure, 1 represents the substrate layer; 2 represents the anode layer; 3 represents the hole injection layer; 4 represents the hole transport layer; 5 represents the electron blocking layer; 6 represents the light-emitting layer; 7 represents the hole blocking layer; 8 represents the electron transport layer; 9 represents the electron injection layer; 10 represents the cathode layer; 11 represents the cover layer.

[0080] Figure 2 is the NMR spectrum of Compound 26. DETAILED DESCRIPTION OF THE INVENTION

[0081] Hereinafter, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The description of at least one exemplary embodiment is actually only illustrative and in no way restrictive of the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0082] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0083] In the present invention, unless otherwise specified, HOMO means the highest occupied molecular orbital of a molecule, and LUMO means the lowest unoccupied molecular orbital of a molecule. In addition, in the present invention, the HOMO and LUMO energy levels are represented by absolute values, and the comparison between energy levels is also a comparison of the magnitudes of their absolute values. Those skilled in the art know that the greater the absolute value of an energy level, the lower the energy of that energy level.

[0084] In the present invention, when a layer or element is referred to as being "on" another layer or substrate, the layer or element may be directly on the other layer or substrate, or there may also be an intermediate layer. In addition, it will also 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 also be one or more intermediate layers. The same reference numerals throughout the text denote the same elements.

[0085] In the present invention, when describing electrodes, organic electroluminescent devices, and other structures, terms indicating orientation such as "above", "below", "top", and "bottom" only represent the orientation in a certain specific state, and do not mean that the related structures can only exist in the described orientation; on the contrary, if the structure can be transformed in position, for example, inverted, the orientation of the structure is changed accordingly. Specifically, in the present invention, the "bottom" and "lower" sides of an electrode refer to the side of the electrode close to the substrate during the preparation process, and the opposite side away from the substrate is the "top" and "upper" sides.

[0086] In this specification, the term "substituted" means that one or more hydrogen atoms on a specified atom or group are replaced by a specified group, provided that it does not exceed the normal valence of the specified atom under the existing circumstances.

[0087] In this specification, the hole characteristic means the conductive characteristic that can supply electrons when an electric field is applied and is attributed to the highest occupied molecular orbital (HOMO) level, and the characteristic that the holes formed in the anode are easily injected into the light-emitting layer and transported in the light-emitting layer.

[0088] In this specification, the electron characteristic means the conductive characteristic that can accept electrons when an electric field is applied and is attributed to the lowest unoccupied molecular orbital (LUMO) level, and the characteristic that the electrons formed in the cathode are easily injected into the light-emitting layer and transported in the light-emitting layer.

[0089] Organic electroluminescent device

[0090] The present invention provides an organic electroluminescent device using a diarylamine compound of general formula (1).

[0091] In an exemplary embodiment of the present invention, the organic electroluminescent device may include an anode, a hole transport region, a light-emitting region, an electron transport region, and a cathode.

[0092] The organic electroluminescent device of the present invention can be a bottom-emitting organic electroluminescent device, a top-emitting organic electroluminescent device, or a stacked organic electroluminescent device, and there is no specific limitation thereto.

[0093] In the organic electroluminescent device of the present invention, any substrate commonly used in organic electroluminescent devices can also be used. Examples thereof are 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 stabilities, transparencies, surface smoothnesses, and water resistances. Depending on the nature of the substrate, its usage direction is different. In the present invention, a transparent substrate is preferably used. The thickness of the substrate is not particularly limited.

[0094] Anode

[0095] Preferably, an anode can be formed on the substrate. In the present invention, the anode and the cathode face each other. The anode can be made of a conductor having a relatively high work function to assist hole injection, and can be, for example, a metal such as nickel, platinum, copper, zinc, silver, or an alloy thereof; a metal oxide such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); a combination of a metal and a 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, and is generally 50 - 500 nm, preferably 70 - 300 nm, and more preferably 100 - 200 nm. In the present invention, a combination of a metal and a metal oxide, ITO and Ag, is preferably used.

[0096] Cathode

[0097] The cathode can be made of a conductor having a relatively low work function to assist electron injection, and can be, for example, a metal or an alloy thereof such as magnesium, calcium, sodium, potassium, titanium, indium, aluminum, silver, tin, and combinations thereof; multilayer structure materials such as LiF / Al, Li2O / Al, and BaF2 / Ca, but is not limited thereto. The thickness of the cathode depends on the material used, and is generally 10 - 50 nm, preferably 15 - 20 nm.

[0098] Light-emitting region

[0099] In the present invention, the light-emitting region may be disposed between the anode and the cathode and may include at least one host material and at least one guest material. As the host material and the guest material of the light-emitting region of the organic electroluminescent device of the present invention, the light-emitting layer materials known in the prior art for organic electroluminescent devices can be used. The host material may be, for example, a thiazole derivative, a benzimidazole derivative, a polydialkylfluorene derivative, or 4,4'-bis(9-carbazolyl)biphenyl (CBP). The host material may use a compound containing an anthracene group. The guest material may be, for example, quinacridone, coumarin, rubrene, perylene and its derivatives, benzopyran derivatives, rhodamine derivatives, or aminostyrene derivatives.

[0100] In a preferred embodiment of the present invention, the light-emitting region contains one or two host material compounds.

[0101] In a preferred embodiment of the present invention, the light-emitting region contains two host material compounds, and the two host material compounds form an exciplex.

[0102] In a preferred embodiment of the present invention, the host material used in the light-emitting region is selected from one or more of the following compounds BH-1 - BH-11:

[0103]

[0104]

[0105] In the present invention, the light-emitting region may include a phosphorescent or fluorescent guest material to improve the fluorescence or phosphorescence characteristics of the organic electroluminescent device. Specific examples of the phosphorescent guest material include metal complexes of iridium, platinum, etc. For the fluorescent guest material, those commonly used in the art can be used. In a preferred embodiment of the present invention, the guest material used in the light-emitting film layer is selected from one of the following compounds BD-1 to BD-10:

[0106]

[0107] In the light-emitting region of the present invention, the ratio of the host material to the guest material used is 99:1 - 70:30, preferably 99:1 - 85:15, and more preferably 97:3 - 87:13, by mass.

[0108] The thickness of the light-emitting region may be 10 - 50 nm, preferably 15 - 30 nm, but the thickness is not limited to this range.

[0109] Hole transport region

[0110] In the organic electroluminescent device of the present invention, a hole transport region is disposed between the anode and the light-emitting region, which includes a hole injection layer, a hole transport layer, and an electron blocking layer.

[0111] Hole injection layer

[0112] The hole injection material used in the hole injection layer (also referred to as the anode interface buffer layer) is a material that can sufficiently accept holes from the anode at a low voltage, 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 present invention, the hole injection layer is a mixed film layer of a host organic material and a P-type doping material. In order to enable holes to be smoothly injected from the anode into the organic film layer, the HOMO energy level of the host organic material and the P-type doping material must have certain characteristics to expect the occurrence of a charge transfer state between the host material and the doping material, achieve ohmic contact between the hole injection layer and the anode, and thus achieve efficient injection of holes from the electrode to the hole injection layer. This characteristic is summarized as: the difference between the HOMO energy level of the host material and the LUMO energy level of the P-type doping material ≤ 0.4 eV. Therefore, for hole-type host materials with different HOMO energy levels, different P-type doping materials need to be selected to match them in order to achieve ohmic contact at the interface and improve the hole injection effect.

[0113] Preferably, specific examples of the host organic material include: metal porphyrins, oligothiophenes, organic materials of diarylamines, hexanitrile hexaazapentacene, quinacridone-based organic materials, perylene-based organic materials, anthraquinone, polyaniline-based and polythiophene-based conductive polymers; but not limited thereto. Preferably, the host organic material is an organic material of diarylamines.

[0114] Preferably, the P-type doping material is a compound having charge conductivity selected from the following: quinone derivatives or metal oxides, such as tungsten oxide and molybdenum oxide, but not limited thereto.

[0115] In a preferred embodiment of the present invention, the P-type doping material used is any one of the following compounds P-1 to P-8:

[0116] In an embodiment of the present invention, the ratio of the host organic material to the P-type doping material used is 99:1 - 95:5, preferably 99:1 - 97:3, based on mass.

[0117] In a preferred embodiment of the present invention, the hole injection layer is a mixed film layer of a diarylamine compound and a P-type doping material, and the diarylamine compound is a diarylamine compound of the general formula (1).

[0118] 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.

[0119] Hole transport layer

[0120] In the organic electroluminescent device of the present invention, the hole transport layer can be disposed on the hole injection layer. The hole transport material is a suitable material having a high hole mobility, which can accept holes from the anode or the hole injection layer and transfer the holes into the light-emitting layer. Specific examples thereof include: bisarylamine organic materials, conductive polymers, block copolymers having both a conjugated part and a non-conjugated part, etc., but are not limited thereto. In a preferred embodiment, the hole transport layer contains the bisarylamine organic compound represented by the same general formula (1) as the hole injection layer.

[0121] 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.

[0122] Electron blocking layer

[0123] In the organic electroluminescent device of the present invention, the electron blocking layer can be disposed between the hole transport layer and the light-emitting layer, and in particular, contacts the light-emitting layer. The electron blocking layer is provided to contact the light-emitting layer, and thus, the 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 electron blocking layer material is selected from carbazole-based bisarylamine derivatives. The thickness of the electron blocking layer can be 5 - 20 nm, preferably 8 - 15 nm, but the thickness is not limited to this range.

[0124] Electron transport region

[0125] 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 a hole blocking layer, an electron transport layer, and an electron injection layer, but is not limited thereto.

[0126] Electron injection layer

[0127] The electron injection layer can be disposed between the electron transport layer and the cathode. The electron injection layer material is usually preferably a material having a low work function, so that electrons can be easily injected into the organic functional material layer. Preferably, the electron injection layer material is an N-type metal material. As the electron injection layer material of the organic electroluminescent device of the present invention, the electron injection layer materials known in the prior art for organic electroluminescent devices can be used, for example, lithium; lithium salts such as lithium 8-hydroxyquinoline, lithium fluoride, lithium carbonate or lithium azide; or cesium salts, cesium fluoride, cesium carbonate or cesium azide. The thickness of the electron injection layer of the present invention can 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.

[0128] Electron transport layer

[0129] The electron transport layer can be disposed above the light-emitting film layer or (if present) the hole blocking layer. The electron transport layer material is a material that can easily receive electrons from the cathode and transfer the received electrons to the light-emitting layer. A material with a 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. For example, metal complexes of hydroxyquinoline derivatives represented by Alq3, BAlq, and LiQ, various rare earth metal complexes, triazole derivatives, 2,4-bis(9,9-dimethyl-9H-fluoren-2-yl)-6-(naphthalen-2-yl)-1,3,5-triazine (CAS No.: 1459162-51-6) and other triazine derivatives, 2-(4-(9,10-bis(naphthalen-2-yl)anthracen-2-yl)phenyl)-1-phenyl-1H-benzo[d]imidazole (CAS No.: 561064-11-7, commonly known as LG201) and other imidazole derivatives, oxadiazole derivatives, etc.

[0130] In the preferred organic electroluminescent device of the present invention, the electron transport layer contains an azo compound of the general formula (4):

[0131]

[0132] Wherein, Ar5, Ar6, and Ar7 are each independently selected from a substituted or unsubstituted C6-C 30 aryl group, a substituted or unsubstituted C2-C containing one or more heteroatoms 30 heterocyclic group;

[0133] L3 represents a single bond, a substituted or unsubstituted C6-C 30 arylene group, a substituted or unsubstituted C2-C containing one or more heteroatoms 30 heteroarylene group; X1, X2, and X3 each independently represent N or CH, and at least one of X1, X2, and X3 represents N;

[0134] Each of the heteroatoms is independently selected from N, O, or S;

[0135] The substituents for the substitution groups are one or more of a deuterium atom, a phenyl group, a naphthyl group, a biphenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a pyridyl group, or a pyrimidinyl group.

[0136] Preferably, Ar5, Ar6, and Ar7 each independently represent a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted pyridyl group, a substituted or unsubstituted pyrimidinyl group, a substituted or unsubstituted dibenzothiophene, or a substituted or unsubstituted quinolinyl group;

[0137] L3 represents a single bond, a phenylene group, a biphenylene group, or a naphthylene group;

[0138] The substituents for the substituent groups are one or two of a deuterium atom, a phenyl group, a naphthyl group, a biphenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a pyridyl group, or a pyrimidinyl group.

[0139] Preferably, the substituted or unsubstituted C6-C 30 aryl and / or the substituted or unsubstituted C2-C 30 heteroaryl refers to a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted phenanthrenyl group, a substituted or unsubstituted condensed tetraphenyl group, a substituted or unsubstituted pyrenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted p-terphenyl group, a substituted or unsubstituted m-terphenyl group, a substituted or unsubstituted group, a substituted or unsubstituted terphenylene group, a substituted or unsubstituted perylenyl group, a substituted or unsubstituted indenyl group, a substituted or unsubstituted furanyl group, a substituted or unsubstituted thiophenyl group, a substituted or unsubstituted pyrrolyl group, a substituted or unsubstituted pyrazolyl group, a substituted or unsubstituted imidazolyl group, a substituted or unsubstituted triazolyl group, a substituted or unsubstituted oxazolyl group, a substituted or unsubstituted thiazolyl group, a substituted or unsubstituted oxadiazolyl group, a substituted or unsubstituted thiadiazolyl group, a substituted or unsubstituted pyridyl group, a substituted or unsubstituted pyrimidinyl group, a substituted or unsubstituted pyrazinyl group, a substituted or unsubstituted triazinyl group, a substituted or unsubstituted benzofuranyl group, a substituted or unsubstituted benzothiophenyl group, a substituted or unsubstituted benzimidazolyl group, a substituted or unsubstituted indolyl group, a substituted or unsubstituted quinolinyl group, a substituted or unsubstituted isoquinolinyl group, a substituted or unsubstituted quinazolinyl group, a substituted or unsubstituted quinoxalinyl group, a substituted or unsubstituted naphthyridinyl group, a substituted or unsubstituted benzoxazinyl group, a substituted or unsubstituted benzothiazinyl group, a substituted or unsubstituted acridinyl group, a substituted or unsubstituted phenazinyl group, a substituted or unsubstituted phenothiazinyl group, a substituted or unsubstituted phenoxazinyl group, a substituted or unsubstituted fluorene group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted carbazolyl group, a combination thereof, or a fused ring of the foregoing group combinations, but not limited thereto.

[0140] The substituted or unsubstituted C6-C 30 arylene, the substituted or unsubstituted C2-C 30Hetarylene refers to substituted or unsubstituted phenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted anthrylene, substituted or unsubstituted phenanthrylene, substituted or unsubstituted benzo[ghi]tetraphenylene, substituted or unsubstituted pyrenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted p-terphenyl-4,4'-diyl, substituted or unsubstituted m-terphenyl-3,3'-diyl, substituted or unsubstituted -ylene, substituted or unsubstituted terphenylene-4,4''-diyl, substituted or unsubstituted perylenylene, substituted or unsubstituted indenylene, substituted or unsubstituted furylene, substituted or unsubstituted thienylene, substituted or unsubstituted pyrrolylene, substituted or unsubstituted pyrazolylene, substituted or unsubstituted imidazolylene, substituted or unsubstituted triazolylene, substituted or unsubstituted oxazolylene, substituted or unsubstituted thiazolylene, substituted or unsubstituted oxadiazolylene, substituted or unsubstituted thiadiazolylene, substituted or unsubstituted pyridinylene, substituted or unsubstituted pyrimidinylene, substituted or unsubstituted pyrazinylene, substituted or unsubstituted triazinylene, substituted or unsubstituted benzofurylene, substituted or unsubstituted benzothienylene, substituted or unsubstituted benzimidazolylene, substituted or unsubstituted indolylene, substituted or unsubstituted quinolinylene, substituted or unsubstituted isoquinolinylene, substituted or unsubstituted quinazolinylene, substituted or unsubstituted quinoxalinylene, substituted or unsubstituted naphthyridinylene, substituted or unsubstituted benzoxazinylene, substituted or unsubstituted benzothiazinylene, substituted or unsubstituted acridinylene, substituted or unsubstituted phenazinylene, substituted or unsubstituted phenothiazinylene, substituted or unsubstituted phenoxazinylene, substituted or unsubstituted fluorene-9,9'-diyl, substituted or unsubstituted dibenzofurylene, substituted or unsubstituted dibenzothienylene, substituted or unsubstituted carbazolylene, their combinations or polycyclic rings formed by combinations of the foregoing groups, but not limited thereto.

[0141] In a preferred embodiment of the present invention, the electron transport layer comprises any one of the compounds selected from the following:

[0142]

[0143]

[0144] In a more preferred embodiment of the present invention, the electron transport layer comprises any one of the compounds selected from the following:

[0145]

[0146] In a preferred embodiment of the present invention, in addition to the compound of formula (4), the electron transport layer further comprises other compounds conventionally used in the electron transport layer, for example, Alq3, LiQ, preferably LiQ. In a more preferred embodiment of the present invention, the electron transport layer is composed of one of the compounds of formula (4) and one of the other compounds conventionally used in the electron transport layer (preferably LiQ).

[0147] The hole injection and transport rates in the hole transport region containing the bisarylamine compound of the present invention can be well matched with the electron injection and transport rates. Preferably, the hole injection and transport rates in the hole transport region containing the bisarylamine compound of the present invention can be better matched with the electron injection and transport rates in the electron transport region containing the azacyclic derivative of formula (4).

[0148] Therefore, in a particular embodiment of the present invention, using one or more or consisting of the azacyclic compounds of formula (4) in the electron transport region, in combination with the hole transport region containing the bisarylamine compound of the present invention, relatively better technical effects are achieved.

[0149] 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.

[0150] Cover layer

[0151] In order to improve the light extraction efficiency of the organic electroluminescent device, a light extraction layer (i.e., CPL layer, also known as the cover layer) can also be added on the cathode of the device. According to the principles of optical absorption and refraction, the refractive index of the CPL cover layer material should be as high as possible, and the light absorption coefficient should be as small as possible. Any material well known in the art can be used as the CPL layer material, such as Alq3, or N4,N4'-diphenyl-N4,N4'-bis(9-phenyl-3-carbazolyl)biphenyl-4,4'-diamine. The thickness of the CPL cover layer is usually 5 - 300 nm, preferably 20 - 100 nm and more preferably 40 - 80 nm.

[0152] The organic electroluminescent device of the present invention may further include a packaging structure. The packaging structure can be a protective structure for preventing external substances such as moisture and oxygen from entering the organic layer of the organic electroluminescent device. The packaging structure can be, for example, a can, such as a glass can or a metal can; or a thin film covering the entire surface of the organic layer.

[0153] The present invention also relates to a method for preparing an organic electroluminescent device, which comprises laminating an anode, a hole injection layer, a hole transport layer, an electron blocking layer, an organic film layer, an electron transport layer, an electron injection layer and a cathode successively on a substrate, and optionally a covering layer. In this regard, vacuum deposition, vacuum evaporation, spin coating, casting, LB method, inkjet printing, laser printing or LITI methods can be used, but are not limited thereto. In the present invention, it is preferred to use a vacuum evaporation method to form the various layers. Those skilled in the art can conventionally select various process conditions in the vacuum evaporation method according to actual needs.

[0154] In addition, it should be noted that the materials used to form each layer described in the present invention can be formed into a film alone and used as a single layer, or can be mixed with other materials to form a film and used as a single layer. It can also be a stacked structure between layers formed into films alone, a stacked structure between layers formed into films after mixing, or a stacked structure of layers formed into films alone and layers formed into films after mixing.

[0155] The present invention also relates to a full-color display device having three pixels of red, green and blue, including the organic electroluminescent device of the present invention, in particular a flat panel display device. The display device may also include at least one thin film transistor. The thin film transistor may include a gate electrode, a source electrode and a drain electrode, a gate insulating layer and an active layer, wherein one of the source electrode and the drain electrode may be electrically connected to the anode of the organic electroluminescent device. The active layer may include crystalline silicon, amorphous silicon, an organic semiconductor or an oxide semiconductor, but is not limited thereto.

[0156] Example 1: Synthesis of Compound 299

[0157] Step (1)

[0158] Step (2)

[0159] In a three-necked flask, under nitrogen protection, add 0.01 mol of raw material A-1, 0.012 mol of raw material B-1, and 150 ml of toluene, stir and mix, then add 5×10 -5 mol Pd2(dba)3,5×10 -5 mol tri-tert-butylphosphine, 0.03 mol sodium tert-butoxide, heated to 105°C, refluxed for 24 hours, sampled the plate, showed no amino compound remaining, the reaction was complete; cooled naturally to room temperature, filtered, the filtrate was evaporated until there was no fraction, passed through a neutral silica gel column, and the intermediate P-1 was obtained. LC-MS ([M+H] + ): The measured value is 568.33.

[0160] Under a nitrogen atmosphere, 0.06 mol of intermediate P-1 was added to a three-necked flask, and it was dissolved with a mixed solvent (300 ml of toluene, 90 ml of H2O). Nitrogen was passed through and stirred for 1 hour, then 0.05 mol of raw material C-1, 0.1 mol of K2CO3, and 0.005 mol of Pd(PPh3)4 were slowly added. It was heated to 90 °C and reacted for 8 hours. The reaction was observed by thin-layer chromatography (TLC) until the reaction was complete. After naturally cooling to room temperature, water was added to the reaction system for extraction, and liquid separation was carried out. The organic phase was rotary evaporated under reduced pressure until there was no distillate. The obtained substance was purified by a silica gel column to obtain the target product. Elemental analysis structure (molecular formula C 59 H 40 N2): The measured values were: C, 91.27; H, 5.16; N, 3.60. LC-MS([M+H] + ): The measured value was 777.08.

[0161] The following compounds were prepared in the same manner as in Example 1, as shown in Table 1 below;

[0162] Table 1

[0163]

[0164]

[0165] The NMR spectrum of Compound 26 is as Figure 2 shown. It can be seen from the figure that 1 H NMR (400 MHz, Chloroform-d) δ 7.76–7.73 (m, 3H), 7.67 (d, 1H), 7.53 (dd, 1H), 7.31–7.18 (m, 4H), 7.08–6.84 (m, 28H), 6.55 (d, 1H).

[0166] Example 2: Synthesis of intermediate S-1

[0167]

[0168] Under a nitrogen atmosphere, 0.06 mol of raw material E-1 was added to a three-necked flask, and it was dissolved with a mixed solvent (300 ml of toluene, 90 ml of H2O). Nitrogen was passed through and stirred for 1 hour, then 0.05 mol of raw material D-1, 0.1 mol of K2CO3, and 0.005 mol of Pd(PPh3)4 were slowly added. It was heated to 90 °C and reacted for 8 hours. The reaction was observed by thin-layer chromatography (TLC) until the reaction was complete. After naturally cooling to room temperature, water was added to the reaction system for extraction, and liquid separation was carried out. The organic phase was rotary evaporated under reduced pressure until there was no distillate. The obtained substance was purified by a silica gel column to obtain intermediate R-1. LC-MS([M+H] +): Measured value: 233.25.

[0169] In a three-necked flask, under nitrogen protection, add 0.01 mol of intermediate R-1, 0.012 mol of raw material F-1, and 150 ml of toluene, stir and mix, then add 5×10 -5 mol Pd2(dba)3,5×10 -5 mol tri-tert-butylphosphine, 0.03 mol sodium tert-butoxide, heated to 105°C, refluxed for 24 hours, sampled the plate, showed no amino compound remaining, the reaction was complete; cooled naturally to room temperature, filtered, the filtrate was evaporated until there was no fraction, passed through a neutral silica gel column, and intermediate M-1 was obtained. LC-MS ([M+H] + ): Measured value: 290.07.

[0170] In a three-necked flask, under nitrogen protection, add 0.01 mol of intermediate M-1, 0.012 mol of raw material G-1, and 150 ml of toluene, stir and mix, and then add 5×10 -5 mol Pd2(dba)3,5×10 -5 mol tri-tert-butylphosphine, 0.03 mol sodium tert-butoxide, heated to 105°C, refluxed for 24 hours, sampled the plate, showed no amino compound remaining, the reaction was complete; cooled to room temperature naturally, filtered, the filtrate was evaporated until there was no fraction, passed through a neutral silica gel column, and intermediate S-1 was obtained. LC-MS ([M+H] + ): Measured value: 492.11.

[0171] The synthesis of other intermediates M or S is the same as that of intermediate M-1 or intermediate S-1, except that the raw materials involved are changed. The corresponding raw materials are shown in Table 2 below. Since the raw materials D-1, F-1, and G-1 used in the synthesis process have not changed, they are not listed in Table 2:

[0172] Table 2

[0173]

[0174] The synthesis method of compound 28 is similar to that of compound 26, except that the raw material C-1 in step (2) is replaced by intermediate S-3. The synthesis methods of compounds 349 and 365 are the same as those of compound 28, and the raw materials or intermediates involved are shown in Table 3 below. The synthesis process of compound 290 is similar to that of compound 299, except that the raw material A-1 in step (1) is replaced by intermediate M-8. The synthesis methods of compounds 54, 179, 406 and 412 are similar to those of compound 290, and the raw materials or intermediates involved are shown in Table 3 below:

[0175] Table 3

[0176]

[0177]

[0178] Detection method

[0179] Glass transition temperature Tg: Measured by differential scanning calorimetry (DSC, DSC204F1 differential scanning calorimeter from Netzsch, Germany), with a heating rate of 10 °C / min.

[0180] HOMO energy level: Tested by an ionization energy test system (IPS3) in a vacuum environment.

[0181] Eg energy level: Tested by a double-beam ultraviolet-visible spectrophotometer (model: TU-1901). Based on the ultraviolet spectrophotometry (UV absorption) baseline of the single-layer material film and the rising side of the first absorption peak, a tangent is made, and the value at the intersection of the tangent and the baseline is calculated.

[0182] Hole mobility: The material is made into a single-charge device and measured by the space-charge (induced) limited current method (SCLC).

[0183] Triplet energy level T1: Tested by a Fluorolog-3 series fluorescence spectrometer from Horiba. The test condition for the material is a toluene solution with a concentration of 2×10 -5 mol / L.

[0184] For specific physical property test results, see Table 4.

[0185] Table 4

[0186]

[0187] From the data in Table 4 above, it can be seen that the compound of the present invention has a suitable HOMO energy level, a relatively high hole mobility, and a relatively wide bandgap (Eg), and can be used to realize an organic electroluminescent device with high efficiency, low voltage, and long life.

[0188] Preparation of organic electroluminescent device

[0189] The molecular structural formulas of the materials involved in the following preparation process are shown as follows:

[0190]

[0191] Device comparative example 1

[0192] Prepare an organic electroluminescent device according to the following steps:

[0193] As Figure 1As shown, for the substrate layer 1, the anode layer 2 (Ag (100 nm)) is washed, that is, alkali washing, pure water washing, and drying are carried out in sequence, and then ultraviolet-ozone washing is carried out to remove organic residues on the surface of the anode layer. On the anode layer 2 after the above washing, using a vacuum evaporation device, HT-1 and P-1 with a film thickness of 10 nm are evaporated as the hole injection layer 3, and the mass ratio of HT-1 and P-1 is 97:3. Then, HT-1 with a thickness of 117 nm is evaporated as the hole transport layer 4. Subsequently, EB-1 with a thickness of 10 nm is evaporated as the electron blocking layer 5. After the evaporation of the above electron blocking material is completed, the light-emitting layer 6 of the OLED light-emitting device is fabricated. Its structure includes BH-1 used as the host material and BD-1 used as the doping material for the OLED light-emitting layer 6. The doping ratio of the doping material is 3% by weight, and the film thickness of the light-emitting layer is 20 nm. After the above light-emitting layer 6, HB1 is continuously evaporated with a film thickness of 8 nm as the hole blocking layer 7. On the above hole blocking layer 7, ET-1 and Liq are continuously evaporated, and the mass ratio of ET-1 and Liq is 1:1. The vacuum evaporation film thickness of this material is 30 nm, and this layer is the electron transport layer 8. On the electron transport layer 8, a LiF layer with a film thickness of 1 nm is fabricated through a vacuum evaporation device, and this layer is the electron injection layer 9. On the electron injection layer 9, a Mg:Ag electrode layer with a film thickness of 16 nm is fabricated through a vacuum evaporation device, and the mass ratio of Mg and Ag is 1:9. This layer is used as the cathode layer 10. On the cathode layer 10, 70 nm of CP-1 is vacuum-evaporated as the cover layer 11.

[0194] Device Comparative Examples 2-5

[0195] It is carried out according to the method of Device Comparative Example 1, except that the organic materials in the hole injection layer and the hole transport layer are respectively replaced with the organic materials shown in Table 5.

[0196] Device Examples 1-23

[0197] It is carried out according to the method of Device Comparative Example 1, except that the organic materials in the hole injection layer, the hole transport layer, or the electron transport layer are respectively replaced with the organic materials shown in Table 5.

[0198] Table 5

[0199]

[0200] In the above table, taking Example 1 as an example, "P-1:299 = 3:97 10nm" in the second column table means that the materials used for the hole injection layer are compound 299 and P-type doping material P-1. 3:97 refers to the weight ratio of the P-type doping material to compound 299 being 3:97, and 10nm represents the thickness of this layer; "299 117nm" in the third column table means that the material used is compound 299 and the thickness of this layer is 117nm. And so on for the meanings in other tables.

[0201] After preparing the OLED light-emitting device as described above, the cathode and anode are connected by a known driving circuit, and various performances of the device are measured.

[0202] The measurement performance results of the devices of Examples 1-23 and Comparative Examples 1-5 are shown in Table 5.

[0203] Table 5

[0204]

[0205] Note: LT95 refers to the time taken for the device brightness to decay to 95% of the original brightness at a brightness of 1500 nits.

[0206] Voltage, current efficiency, and color coordinates were measured using an IVL (current-voltage-brightness) test system (Suzhou Fosda Scientific Instruments Co., Ltd.); the current density was 10 mA / cm 2 ;

[0207] The lifetime test system was the EAS-62C type OLED lifetime test system of System Science Co., Ltd. of Japan.

[0208] The high-temperature lifetime refers to the time taken for the device brightness to decay to 80% of the original brightness at 80 °C under a current density of 10 mA / cm 2 ;

[0209] From the results of Comparative Examples 1-5 and Examples 1-23 in Table 5, it can be seen that by using the bis(arylamine) organic compound of the present invention as the hole injection and hole transport layer materials, due to the high carrier transport rate, the voltage of the device is effectively reduced, and the efficiency and lifetime of the device are improved. In particular, in Examples 19-23, the combination of the structure of the present invention and specific electron transport layer materials is used, and this combination method significantly improves the high-temperature lifetime of the device.

Claims

1. A diarylamine organic compound, characterized in that, The structure of the said compound is shown in general formula (1): In general formula (1), a and c each independently represent the number 0 or 1, and a + c = 1; The said R1 - R4 each independently represent one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted furyl group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted benzofuryl group, a substituted or unsubstituted benzothienyl group, a substituted or unsubstituted piperonyl group, a substituted or unsubstituted indenyl group, and the connection mode of R1 and R2 with the main structure in general formula (1) is single - bond substitution or formation of a fused ring; When R3 and R4 each independently represent a substituted or unsubstituted thienyl group or a substituted or unsubstituted furyl group, the connection mode of R3 and R4 with the main structure in general formula (1) is single - bond substitution or formation of a fused ring; The said Ar represents the structure shown in general formula (2) or general formula (3); The said m, n, p, q each represent the number 0, 1 or 2; When p and m both represent 0 and n and q both represent 1, R2 and R3 do not simultaneously represent a phenyl group; When m, n, p, q all represent the number 1, R1 - R4 do not simultaneously represent a phenyl group; m, n, p, q do not simultaneously represent 0; The said Ra and Rb each independently represent a hydrogen atom, a deuterium atom, a methyl group, an ethyl group or a tert - butyl group; The substituents for the substitution groups are a deuterium atom, a methyl group, an ethyl group, a tert - butyl group, a phenyl group, a naphthyl group or a biphenyl group; In the general formula (1) are represented as different groups.

2. The bisarylamine organic compound according to claim 1, wherein The structure of the said compound is shown in general formula (1 - 1): The meanings of the said R1, R2, Ar, m, n, a, c are the same as the definitions in claim 1.

3. The bisarylamine organic compound according to claim 1, wherein The structure of the said compound is shown in general formula (1 - 2): The meanings of the said R2 - R4, Ar, p, q, n, a, c are the same as the definitions in claim 1.

4. The bisarylamine organic compound according to claim 1, wherein The structure of the said compound is shown in general formula (1 - 3): The meanings of the said R1 - R3, Ar, q, m, n, a, c are the same as the definitions in claim 1.

5. The bisarylamine organic compound according to claim 1, wherein The said R1 - R4 each independently represent one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group; the said Ra and Rb each independently represent a hydrogen atom or a deuterium atom.

6. The bisarylamine organic compound according to claim 1, wherein The specific structure of the said compound is any one of the following structures:

7. An organic electroluminescent device, which sequentially includes an anode, a hole transport region, a light-emitting region, an electron transport region, and a cathode, is characterized in that, The said hole - transport region contains the bis - arylamine organic compound described in any one of claims 1 - 6.

8. The organic electroluminescent device according to claim 7, characterized in that, The said hole - transport region includes a hole - injection layer, a hole - transport layer and an electron - blocking layer, and the hole - transport layer and the hole - injection layer contain the bis - arylamine organic compound described in any one of claims 1 - 6.

9. The organic electroluminescent device according to claim 8, characterized in that, The said hole - transport layer contains the bis - arylamine organic compound described in any one of claims 1 - 6, and the hole - injection layer is composed of the bis - arylamine organic compound described in any one of claims 1 - 6 and other conventional P - type doping materials used for the hole - injection layer.

10. The organic electroluminescent device according to claim 7, characterized in that, The said electron - transport region contains the nitrogen - containing heterocyclic compound shown in general formula (4): Among them, Ar5, Ar6, and Ar7 are each independently selected from substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C2-C containing one or more heteroatoms 30 heterocyclic group; L3 represents a single bond, a substituted or unsubstituted C6-C 30 arylene, a substituted or unsubstituted C2-C containing one or more heteroatoms 30 heteroarylene; X1, X2, X3 each independently represent N or CH, and at least one of X1, X2, X3 represents N; The said heteroatoms each independently are selected from N, O or S; The substituents for the substitution groups are one or more of a deuterium atom, a phenyl group, a naphthyl group, a biphenyl group, a dibenzofuryl group, a dibenzothienyl group, a pyridyl group or a pyrimidinyl group.

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