Compound with bis-arylamine structure and organic electroluminescent device containing compound

Abstract

The invention discloses a compound with a bis-arylamine structure and an organic electroluminescent device containing the compound, and belongs to the technical field of semiconductors. The structure of the bis-arylamine compound is shown in a general formula (1), fluorenyl and phenyl serve as bridging groups, one arylamine is connected with a benzene ring on one side of the fluorenyl through phenylene, the arylamine and the fluorenyl must be located at the ortho-position of the phenylene, the other arylamine is directly connected to a benzene ring on the other side of the fluorenyl through a single bond, and the structure of the bis-arylamine compound is as shown in the general formula (1). Through the connection mode, the compound disclosed by the invention has an excellent hole transport rate, so that when the compound disclosed by the invention is applied as a hole transport material, the efficiency and the service life of a device can be remarkably improved.

Description

[0001] This invention application is based on the divisional application of the prior application number: 2022110292015, the application date: August 26, 2022, and the invention name: A compound with a diaromatic amine structure and an organic electroluminescent device containing the same. Technical Field

[0002] The invention relates to the field of semiconductor technology, in particular to a compound with a diarylamine structure and an organic electroluminescent device containing the compound. Background Art

[0003] The carriers (holes and electrons) in an organic electroluminescent device (OLED) are injected into the device by the two electrodes of the device under the drive of an electric field, and meet in the organic light-emitting layer to recombine and emit light. High-performance organic electroluminescent devices require various organic functional materials to have good photoelectric properties. For example, as a charge transport material, it is required to have good carrier mobility. The injection and transport properties of the hole injection layer materials and hole transport layer materials used in 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 in the recombination area, which is not conducive to the stability of the device. In addition, the reasonable energy level matching of the hole injection layer material and the hole transport layer material is an important factor in improving the efficiency and life of the device. Therefore, how to adjust the balance of holes and electrons and adjust the recombination area has always been an important topic in this field.

[0004] Blue organic electroluminescent devices have always been the weak point in the development of full-color OLEDs. So far, the efficiency and life of blue light devices have been difficult to be comprehensively improved. Therefore, how to improve the performance of such devices is still a crucial issue and challenge facing this field. Currently, most of the blue light host materials used in the market are electron-biased hosts. Therefore, in order to adjust the carrier balance of the light-emitting layer, the hole transport material needs to have excellent hole transport performance. The better the hole injection and transport, the more the recombination area will be adjusted to shift away from the electron blocking layer, thereby emitting light away from the interface, which improves the device performance. At present, with the increase in the transmission rate of electron transport materials, the requirements for hole transport materials are getting higher and higher. However, the current industrialized hole transport materials can no longer meet the demand, which seriously hinders the improvement of the comprehensive performance of blue light devices. Therefore, hole transport materials with higher hole transport rates are urgently needed.

[0005] Because hole transport materials have a thicker film thickness, the heat resistance and amorphousness of the material will have a crucial impact on the life of the device. Materials with poor heat resistance are prone to decomposition during the evaporation process, polluting the evaporation cavity and damaging the life of the device; materials with poor film phase stability will crystallize during the use of the device, reducing the service life of the device. Therefore, hole transport materials are required to have higher film phase stability and decomposition temperature during use. However, the development of materials for stable and effective organic material layers for organic electroluminescent devices has not yet been fully realized. Therefore, it is necessary to continuously develop a new material to better meet the performance requirements of organic electroluminescent devices. Summary of the invention

[0006] In view of the above-mentioned problems existing in the prior art, the present invention proposes a compound of a diaromatic amine structure, with a fluorenyl group and a phenyl group as a bridging group, wherein one aromatic amine is connected to the benzene ring on one side of the fluorenyl group through a phenylene group, and the aromatic amine and the fluorenyl group must be in the ortho position of the phenylene group, and the other aromatic amine is directly connected to the benzene ring on the other side of the fluorenyl group through a single bond. This connection method enables the compound of the present invention to have an excellent hole transport rate, so that the compound of the present invention can be used as a hole transport material, which can significantly improve the efficiency and life of the device.

[0007] The technical solution of the present invention is as follows: a compound with a diaromatic amine structure, wherein the compound structure is shown in the general formula (1):

[0008]

[0009] In the general formula (1), R1 to R4 are independently substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted C2-C 30 heteroaryl;

[0010] The L1 to L4 are independently a straight chain bond, a substituted or unsubstituted C 6-30 Arylene, substituted or unsubstituted C2-C 30 heteroarylene;

[0011] The substituents of the "substituted or unsubstituted" group are selected from deuterium atoms, C 1-10 Alkyl, C 6-30 Aryl, C2-C 30 one or more of heteroaryl groups;

[0012] In the general formula (1), ------ indicates that there is or is no single bond connection between the two side groups;

[0013] The heteroatom is selected from one or more of an oxygen atom, a sulfur atom or a nitrogen atom.

[0014] The present invention also provides an organic electroluminescent device, which comprises an anode, a hole transport region, a light emitting region, an electron transport region and a cathode in sequence, wherein the hole transport region contains the diarylamine structural compound.

[0015] The beneficial technical effect of the present invention is that: the technical core of the present invention is that the compound of the present invention has such a structural feature that the biarylamine structure uses fluorenyl and phenyl as bridging groups, wherein one arylamine is connected to the benzene ring on one side of the fluorenyl through a phenylene group, and the arylamine and the fluorenyl must be in the ortho position of the phenylene group, and the other arylamine is directly connected to the benzene ring on the other side of the fluorenyl through a single bond. This connection method makes the compound of the present invention have the following advantages;

[0016] (1) This connection method enables the compound of the present invention to have excellent hole mobility. The improvement of hole mobility allows more holes to be injected into the main body, and the increase of exciton concentration in the main body increases the TTA efficiency and the exciton utilization rate, thereby improving the device efficiency.

[0017] (2) This connection method enables the compound of the present invention to have a suitable energy level. Reasonable energy level matching makes the injection and conduction of carriers smoother, prevents accumulation at the interface, and is conducive to improving the interface stability. Excellent interface stability is conducive to improving the device life.

[0018] (3) This connection method is beneficial to increasing the glass transition temperature of the molecules and at the same time lowering the evaporation temperature of the molecules. That is to say, even if the molecular weight of the molecules is relatively high, it can ensure a lower evaporation temperature. This excellent performance is not only beneficial to the thermal evaporation of materials, but also controls the thermal decomposition rate of materials, thereby improving the stability of materials in device applications.

[0019] Moreover, for the biarylamine molecular structure characterized by the present invention, the optimization of the ligand connected to the aromatic amine is conducive to further improving the performance of the material. For example, the selection of groups or group derivatives (containing a cyclic structure or a similar group of a substituted structure) with strong planarity or a large structural radius such as biphenyl, furanyl, fluorenyl, phenanthrene, etc. is more conducive to improving the stability and mobility of the material, and is also conducive to the precise control of the HOMO energy level of the material, thereby obtaining a good device application effect of the material.

[0020] The organic functional materials constituting the OLED device include not only hole injection conductive materials but also electron injection conductive 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 compounds of the diarylamine structure matching the characteristic structure of the present invention also require specific electronic materials for matching. Based on the in-depth research of the inventors, the electronic material is preferably a material containing azabenzene structural characteristics, such as triazine materials, pyridine materials, pyrazine materials, etc. or derivatives containing these characteristic groups. The diarylamine structure compound of the present invention is combined with azabenzene ring electron transport material so that electrons and holes are easy to obtain the best balance state, and have high efficiency and excellent lifespan. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a cross-sectional schematic diagram of the organic electroluminescent device of the present invention.

[0022] In the figure: 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 electron blocking 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 CPL layer. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] 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, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0025] In the present invention, unless otherwise specified, HOMO means the highest occupied molecular orbital of a molecule, and the HOMO energy level is expressed in absolute values.

[0026] 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 be intervening layers. In addition, 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 intervening layers. The same reference numerals throughout the text represent the same elements.

[0027] In the present invention, when describing electrodes and organic electroluminescent devices, as well as other structures, the words "upper", "lower", "top" and "bottom" used to indicate orientation only indicate the orientation in a certain state, and do not mean that the related structure can only exist in the orientation described; on the contrary, if the structure can change its position, such as inverted, the orientation of the structure will be changed accordingly. Specifically, in the present invention, the "bottom" or "lower" side of the electrode refers 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" or "upper" side.

[0028] In this specification, the term "substituted" means that one or more hydrogen atoms on a designated atom or group are replaced by a designated group, provided that the normal valency of the designated atom is not exceeded under the existing circumstances.

[0029] In the present specification, the substituted or unsubstituted fluorenyl group refers to a substituted or unsubstituted dimethylfluorenyl group, a substituted or unsubstituted diphenylfluorenyl group, or a substituted or unsubstituted spirofluorenyl group.

[0030] More specifically, the substituted or unsubstituted C6-C 30 Aryl and / or substituted or unsubstituted C2-C 30 The heterocyclic group refers to substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted tetraphenyl, substituted or unsubstituted pyrenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted metaterphenyl, substituted or unsubstituted substituted or unsubstituted triphenylene, substituted or unsubstituted perylene, substituted or unsubstituted indenyl, substituted or unsubstituted furyl, substituted or unsubstituted thienyl, substituted or unsubstituted pyrrolyl, substituted or unsubstituted pyrazolyl, substituted or unsubstituted imidazolyl, substituted or unsubstituted triazolyl, substituted or unsubstituted oxazolyl, substituted or unsubstituted thiazolyl, substituted or unsubstituted oxadiazolyl, substituted or unsubstituted thiadiazolyl, substituted or unsubstituted pyridinyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted pyrazinyl, substituted or unsubstituted triazinyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted benzothiophenyl, substituted or unsubstituted benzimidazolyl, substituted or unsubstituted indolyl, substituted or unsubstituted quinolyl, substituted or unsubstituted isoquinolyl, substituted or unsubstituted quinazolinyl, substituted or unsubstituted quinoxalinyl, substituted or unsubstituted naphthyridinyl, substituted or unsubstituted benzoxazinyl, substituted or unsubstituted benzothiazinyl, substituted or unsubstituted acridinyl, substituted or unsubstituted phenazinyl, substituted or unsubstituted phenathiazinyl, substituted or unsubstituted phenoxazinyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted carbazolyl, combinations thereof, or condensed rings of combinations of the foregoing groups, but are not limited thereto.

[0031] In this specification, substituted or unsubstituted C6-C 30 Arylene or substituted or unsubstituted C2-C 30 Heteroarylene refers to a substituted or unsubstituted C6-C 30 Aryl or substituted or unsubstituted C5-C 30 heterocyclic groups, for example substituted or unsubstituted phenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted anthrylene, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted tetraphenylene, substituted or unsubstituted pyrenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted terphenylene, substituted or unsubstituted metaterphenylene, substituted or unsubstituted terphenylene, substituted or unsubstituted triphenylene, substituted or unsubstituted perylene, 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 benzofuranylene, substituted or unsubstituted benzothiophenylene, substituted or unsubstituted benzimidazolylene, substituted or unsubstituted indolylene, substituted or unsubstituted quinolylene, substituted or unsubstituted isoquinolylene, substituted or unsubstituted quinazolinylene, substituted or unsubstituted quinoxalylene, substituted or unsubstituted naphthyridinylene, substituted or unsubstituted benzoxazinylene, substituted or unsubstituted benzothiazinylene, substituted or unsubstituted acridinylene, substituted or unsubstituted phenazinylene, substituted or unsubstituted phenathiazinylene, substituted or unsubstituted phenoxazinylene, substituted or unsubstituted fluorenylene, substituted or unsubstituted dibenzofuranylene, substituted or unsubstituted dibenzothiophenylene, substituted or unsubstituted carbazolylene, combinations thereof, or fused rings of combinations of the foregoing groups, but are not limited thereto.

[0032] Compounds of biphenylamine structure represented by general formula (1):

[0033]

[0034] In the general formula (1), R1 to R4 are independently substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted C2-C 30 heteroaryl;

[0035] The L1 to L4 are independently a straight chain bond, a substituted or unsubstituted C 6-30 Arylene, substituted or unsubstituted C2-C 30 heteroarylene;

[0036] The substituents of the "substituted or unsubstituted" group are selected from deuterium atoms, C 1-10 Alkyl, C 6-30 Aryl, C2-C 30 one or more of heteroaryl groups;

[0037] In the general formula (1), ------ indicates that there is or is no single bond connection between the two side groups;

[0038] The heteroatom is selected from one or more of an oxygen atom, a sulfur atom or a nitrogen atom.

[0039] In a preferred embodiment, the compound structure is as shown in general formula (1-1) or general formula (1-2):

[0040]

[0041] In the general formula (1-1) and the general formula (1-2), R1 to R4 are independently represented by substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted furanyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzofuranyl;

[0042] The L1 to L4 are independently a straight chain bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, a substituted or unsubstituted terphenylene group, or a substituted or unsubstituted naphthylene group;

[0043] The substituent of the "substituted or unsubstituted" group is selected from one or more of a deuterium atom, a methyl group, an ethyl group, a tert-butyl group, a phenyl group, a naphthyl group, a biphenyl group, a furyl group, a benzofuranyl group, and a dibenzofuranyl group.

[0044] In a preferred embodiment, the compound structure is as shown in general formula (2-1), general formula (2-2), general formula (2-3), general formula (2-4) or general formula (2-5):

[0045]

[0046] In the general formula (2-1) to the general formula (2-5), R1 to R4 are independently substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted C2-C 30 heteroaryl;

[0047] The L1 to L4 are independently a straight chain bond, a substituted or unsubstituted C 6-30 Arylene, substituted or unsubstituted C2-C 30 heteroarylene;

[0048] The substituent of the "substituted or unsubstituted" group is selected from one or more of a deuterium atom, a methyl group, an ethyl group, a tert-butyl group, a phenyl group, a naphthyl group, a biphenyl group, a furyl group, a benzofuranyl group, and a dibenzofuranyl group;

[0049] The heteroatom is selected from one or more of an oxygen atom, a sulfur atom or a nitrogen atom.

[0050] In a preferred embodiment, the compound structure is as shown in the general formula (3-1), the general formula (3-2), the general formula (3-3), the general formula (3-4), the general formula (3-5) or the general formula (3-6):

[0051]

[0052]

[0053] In general formula (3-1) to general formula (3-6), ------ indicates that there is or is no single bond connection between the two side groups;

[0054] The R1, R2, R3, and R4 are independently substituted or unsubstituted C 6-30 Aryl, substituted or unsubstituted C2-C 30 heteroaryl;

[0055] The L1 to L4 are independently a straight chain bond, a substituted or unsubstituted C 6-30 Arylene, substituted or unsubstituted C2-C 30 heteroarylene;

[0056] The substituent of the "substituted or unsubstituted" group is selected from one or more of a deuterium atom, a methyl group, an ethyl group, a tert-butyl group, a phenyl group, a naphthyl group, a biphenyl group, a furyl group, a benzofuranyl group, and a dibenzofuranyl group;

[0057] The heteroatom is selected from one or more of an oxygen atom, a sulfur atom or a nitrogen atom.

[0058] In a preferred embodiment, R1 to R4 are independently substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted furanyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted thienyl, substituted or unsubstituted benzothienyl, substituted or unsubstituted dibenzothienyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted N-phenylcarbazolyl, substituted or unsubstituted 9,9-dimethylfluorenyl, substituted or unsubstituted 9,9-diphenylfluorenyl, substituted or unsubstituted spirofluorenyl;

[0059] The L1 to L4 are independently a straight chain bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, a substituted or unsubstituted terphenylene group, or a substituted or unsubstituted naphthylene group;

[0060] The substituent of the "substituted or unsubstituted" group is selected from one or more of a deuterium atom, a methyl group, an ethyl group, a tert-butyl group, a phenyl group, a naphthyl group, a biphenyl group, a furyl group, a benzofuranyl group, and a dibenzofuranyl group.

[0061] In a preferred embodiment, R1 to R4 are independently represented by: substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted furanyl;

[0062] The L1 to L4 are independently a straight chain bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, a substituted or unsubstituted terphenylene group, or a substituted or unsubstituted naphthylene group;

[0063] The substituent of the "substituted or unsubstituted" group is selected from one or more of a deuterium atom, a methyl group, an ethyl group, a tert-butyl group, a phenyl group, a naphthyl group, a biphenyl group, a furyl group, a benzofuranyl group, and a dibenzofuranyl group.

[0064] In a preferred embodiment, the specific structure of the compound is any one of the following structures:

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074] Organic electroluminescent devices

[0075] The present invention provides an organic electroluminescent device, which comprises an anode, a hole transport region, a light emitting region, an electron transport region and a cathode in sequence, wherein the hole transport region comprises a diaromatic amine structure compound represented by general formula (1).

[0076] In a preferred embodiment, the hole transport region comprises a hole injection layer, a hole transport layer and an electron blocking layer, and the hole transport layer and the hole injection layer comprise a diaromatic amine structure compound represented by general formula (1).

[0077] More preferably, the hole transport layer comprises a diarylamine structure compound represented by the general formula (1), and the hole injection layer comprises a diarylamine structure compound represented by the general formula (1) and other doping materials.

[0078] 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.

[0079] The organic electroluminescent device of the present invention may be a bottom-emitting organic electroluminescent device, a top-emitting organic electroluminescent device, or a stacked organic electroluminescent device, without any particular limitation.

[0080] 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; flexible polyimide (PI) film substrates. Different substrates have different mechanical strengths, thermal stability, transparency, surface smoothness, and waterproofness. Depending on the properties of the substrate, its use direction is different. In the present invention, a transparent substrate is preferably used. The thickness of the substrate is not particularly limited.

[0081] anode

[0082] Preferably, an anode can be formed on a substrate. In the present invention, the anode and the cathode are opposite to each other. The anode can be made of a conductor with a higher work function to facilitate 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 not limited thereto. The thickness of the anode depends on the material used, and is typically 50-500nm, preferably 70-300nm, and more preferably 100-200nm. In the present invention, a combination of a metal and a metal oxide, ITO and Ag, is preferably used.

[0083] cathode

[0084] The cathode can be made of a conductor with a lower work function to facilitate electron injection, such as a metal or its alloy, such as magnesium, calcium, sodium, potassium, titanium, indium, aluminum, silver, tin, and combinations thereof; a multilayer structure material, such as LiF / Al, Li2O / Al, and BaF2 / Ca, but not limited thereto. The thickness of the cathode depends on the material used, and is generally 10-50 nm, preferably 15-20 nm.

[0085] Emitting Area

[0086] In the present invention, the light-emitting region may be arranged 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 for organic electroluminescent devices known in the prior art may 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.

[0087] In a preferred embodiment of the present invention, the light emitting region comprises one or two host material compounds.

[0088] In a preferred embodiment of the present invention, the light-emitting region comprises two host material compounds, and the two host material compounds can form an exciplex.

[0089] In a preferred embodiment of the present invention, the host material of the light-emitting region is selected from one or more of the following compounds BH-1 to BH-11:

[0090]

[0091] In the present invention, the light-emitting region may contain a phosphorescent or fluorescent guest material to improve the fluorescent or phosphorescent properties of the organic electroluminescent device. Specific examples of phosphorescent guest materials include metal complexes of iridium, platinum, etc. For fluorescent guest materials, those commonly used in the art can be used. In a preferred embodiment of the present invention, the guest material of the light-emitting film layer used is selected from one of the following compounds BD-1 to BD-10:

[0092]

[0093] 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, based on mass.

[0094] 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.

[0095] Hole transport region

[0096] In the organic electroluminescent device of the present invention, the hole transport region is disposed between the anode and the light emitting region, and includes a hole injection layer, a hole transport layer and an electron blocking layer.

[0097] Hole injection layer

[0098] The hole injection material used in the hole injection layer (also called the anode interface buffer layer) is a material that can fully 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 main organic material and a P-type doping material. In order to smoothly inject holes from the anode into the organic film layer, the HOMO energy level of the main organic material must have certain characteristics with the P-type doping material, so that it is expected to realize the occurrence of charge transfer states between the main material and the doping material, and realize the ohmic contact between the hole injection layer and the anode, thereby realizing efficient injection of holes from the electrode to the hole injection layer. This feature is summarized as: the difference between the HOMO energy level of the main material and the LUMO energy level of the P-type doping material is ≤0.4eV. Therefore, for hole-type main 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.

[0099] Preferably, specific examples of the host organic material include: metal porphyrin, oligothiophene, aromatic amine organic material, hexanitrile hexaazatriphenylene, quinacridone organic material, perylene organic material, anthraquinone, and polyaniline and polythiophene conductive polymers; but are not limited thereto. Preferably, the host organic material is an aromatic amine organic material.

[0100] 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.

[0101] In a preferred embodiment of the present invention, the P-type doping material used is selected from any one of the following compounds HI-1 to HI-8:

[0102]

[0103] In one 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.

[0104] In a preferred embodiment of the present invention, the hole injection layer is a mixed film layer of a compound of an aromatic amine structure and a P-type doping material, and the compound of an aromatic amine structure is a compound of a diaromatic amine structure represented by the general formula (1).

[0105] The thickness of the hole injection layer of the present invention may be 5-20 nm, preferably 8-15 nm, but the thickness is not limited to this range.

[0106] Hole transport layer

[0107] In the organic electroluminescent device of the present invention, a hole transport layer may be disposed above 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 to the light-emitting layer. In a preferred embodiment, the hole transport layer comprises a compound of a biphenylamine structure represented by the same general formula (1) as the hole injection layer.

[0108] The thickness of the hole transport layer of the present invention may be 80-200 nm, preferably 100-150 nm, but the thickness is not limited to this range.

[0109] Electron blocking layer

[0110] In the organic electroluminescent device of the present invention, the electron blocking layer may be disposed between the hole transport layer and the light emitting layer, and in particular in contact with the light emitting layer. The electron blocking layer is disposed to contact the light emitting layer, and therefore, 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 aromatic amine derivatives. The thickness of the electron blocking layer may be 5-20 nm, preferably 8-15 nm, but the thickness is not limited to this range.

[0111] The present invention does not deny the principle of substrate matching of traditional hole-type materials, but further superimposes on the physical property parameters of traditional material screening, that is, it recognizes the influence of HOMO energy level, carrier mobility, film phase stability, thermal stability of materials, etc. on the hole injection efficiency of organic electroluminescent devices. On this basis, the material screening conditions are further increased, and then by selecting more excellent organic electroluminescent materials for device matching, the accuracy of material selection for preparing high-performance organic electroluminescent devices is improved.

[0112] Electron transport region

[0113] 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 an electron transport layer and an electron injection layer, but is not limited thereto.

[0114] Electron injection layer

[0115] The electron injection layer may be disposed between the electron transport layer and the cathode. The electron injection layer material is generally preferably a material having a low work function so that electrons are 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 material for organic electroluminescent devices known in the prior art can be used, for example, lithium; lithium salts, such as 8-hydroxyquinoline lithium, 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 0.1-5nm, preferably 0.5-3nm and more preferably 0.8-1.5nm, but the thickness is not limited to this range.

[0116] Electron transport layer

[0117] The electron transport layer may be disposed on the light-emitting film layer or (if present) the hole blocking layer. The electron transport layer material is a material that easily receives electrons from the cathode and transfers the received electrons to the light-emitting layer. Preferably, the material has a high electron mobility. As the electron transport layer of the organic electroluminescent device of the present invention, the electron transport layer materials for organic electroluminescent devices known in the prior art 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-fluorene-2-yl)-6-(naphthalene-2-yl)-1,3,5-triazine (CAS No.: 1459162-51-6) and other triazine derivatives, 2-(4-(9,10-di(naphthalene-2-yl)anthracene-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.

[0118] In a preferred organic electroluminescent device of the present invention, the electron transport region comprises a nitrogen heterocyclic compound represented by the following general formula (4):

[0119]

[0120] In the general formula (4), Ar1, Ar2, and Ar3 are independently substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C2-C 30 One of the heterocyclic groups;

[0121] L is selected from a single bond, a substituted or unsubstituted C6-C 30 Arylene, substituted or unsubstituted C2-C 30 A heterocyclylene group;

[0122] X1, X2, and X3 independently represent N or C-(H), and at least one of X1, X2, and X3 represents N;

[0123] The substituents of the "substituted or unsubstituted" group are optionally selected from deuterium, tritium, C 1-10 Alkyl, C6-C 30 Aryl, C2-C 30 one or more of heteroaryl groups;

[0124] The heteroatom is selected from one or more of an oxygen atom, a sulfur atom or a nitrogen atom.

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

[0126]

[0127] In a more preferred embodiment of the present invention, the electron transport layer comprises any one of the compounds selected from the following:

[0128]

[0129] In a preferred embodiment of the present invention, in addition to the compound of formula (3), the electron transport layer also includes other compounds conventionally used in electron transport layers, 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 (3) and one of the other compounds conventionally used in electron transport layers (preferably Liq).

[0130] The hole injection and transport rates of the hole transport region containing the compound 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 compound of the present invention can be better matched with the electron injection and transport rates of the electron transport region containing the nitrogen heterocyclic derivative of general formula (3).

[0131] Therefore, in a particular embodiment of the present invention, an electron transport region comprising one or more nitrogen heterocyclic derivatives of the general formula (4) or consisting thereof is used in combination with a hole transport region comprising the compound of the present invention to achieve relatively better technical effects.

[0132] The thickness of the electron transport layer of the present invention may be 10-80 nm, preferably 20-60 nm, and more preferably 25-45 nm, but the thickness is not limited to this range.

[0133] Covering

[0134] In order to improve the light extraction efficiency of the organic electroluminescent device, a light extraction layer (i.e., CPL layer, also called covering layer) may be added to the cathode of the device. According to the principles of optical absorption and refraction, the refractive index of the CPL covering layer material should be as high as possible, and the absorption coefficient should be as small as possible. 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 covering layer is generally 5-300 nm, preferably 20-100 nm and more preferably 40-80 nm.

[0135] The organic electroluminescent device of the present invention may further include an encapsulation structure. The encapsulation structure may be a protective structure that prevents foreign substances such as moisture and oxygen from entering the organic layer of the organic electroluminescent device. The encapsulation structure may be, for example, a can, such as a glass can or a metal can; or a thin film covering the entire surface of the organic layer.

[0136] Hereinafter, an organic electroluminescent device according to an embodiment of the present invention is described.

[0137] In the accompanying drawings, the thickness of layers, films, substrates, regions, etc., is exaggerated for clarity. Throughout the specification, the same reference numerals represent the same elements. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "located" "on" another element, it can be directly located on the other element or there can also be intervening elements. In contrast, when an element is referred to as being "directly located" "on" another element, there are no intervening elements.

[0138] Figure 1 is a schematic cross-sectional view of an organic electroluminescent device according to an embodiment of the present invention.

[0139] See also Figure 1 , 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 electron blocking 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 CPL layer.

[0140] 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.

[0141] 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.

[0142] Exemplary embodiments have been disclosed herein, and although specific terms are used therein, these terms are used and interpreted only as general and descriptive meanings, and not for limiting purposes. In some cases, as will be apparent to those of ordinary skill in the art with the filing of this application, unless specifically indicated, the features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with the features, characteristics, and / or elements described in conjunction with other embodiments. Accordingly, it will be understood by those skilled in the art that various changes may be made in form and detail without departing from the spirit and scope of the invention.

[0143] The following examples are intended to better explain the present invention, but the scope of the present invention is not limited thereto.

[0144] Example

[0145] Unless otherwise specified, various materials used in the following examples and comparative examples are commercially available or can be obtained by methods known to those skilled in the art.

[0146] Synthesis of intermediates

[0147] Synthesis of intermediate B-3:

[0148]

[0149] In a three-necked flask, under nitrogen protection, add 0.02 mol of raw material D-1, 0.022 mol of raw material E-1, and 250 ml of toluene, stir and mix, and then add 1.1×10 -4 mol Pd2(dba)3,1.1×10 -4 mol P(t-Bu)3, 0.05mol sodium tert-butoxide, heated to 110°C, refluxed for 21 hours; cooled to room temperature naturally, filtered, the filtrate was evaporated under reduced pressure, and the crude product was purified by silica gel column chromatography (eluent: hexane: CH2Cl2 = 5:1) to obtain the target product intermediate B-3. LC-MS: measured value: 236.18 ([M+H]+), theoretical value: 235.10.

[0150] The following intermediates were prepared using the same method as intermediate B-3, except that different raw materials D and E were used or different equivalents of raw materials D and E were used. The raw materials used in the synthesis process are shown in the following table:

[0151]

[0152] Synthesis of intermediate A-3:

[0153]

[0154] In a three-necked flask, under nitrogen protection, add 0.01 mol of intermediate B-3, 0.012 mol of raw material F-1, and 150 ml of toluene, stir and mix, and then add 5×10 -5 mol Pd2(dba)3,5×10 -5 mol P(t-Bu)3, 0.03mol sodium tert-butoxide, heated to 110°C, refluxed for 28 hours; cooled to room temperature naturally, filtered, the filtrate was evaporated under reduced pressure, and the crude product was purified by silica gel column chromatography (eluent: hexane: CH2Cl2 = 5:1) to obtain the target product intermediate A-3. LC-MS: measured value: 438.07 ([M+H]+), theoretical value: 437.22.

[0155] The following intermediate A was prepared using the same method as intermediate A-3, except that different intermediate B or raw material F was used. The intermediates and raw materials used in the synthesis process are shown in the following table:

[0156]

[0157]

[0158] Synthesis Example

[0159] Example 1: Synthesis of Compound 1:

[0160]

[0161] (1) In a three-necked flask, under nitrogen protection, add 0.01 mol of intermediate B-1, 0.012 mol of raw material M-1, and 150 ml of toluene, stir and mix, then add 5×10 -5 mol Pd2(dba)3,5×10 -5 mol P(t-Bu)3, 0.03mol sodium tert-butoxide, heated to 110°C, refluxed for 24 hours; cooled to room temperature naturally, filtered, the filtrate was evaporated under reduced pressure, and the crude product was purified by silica gel column chromatography (eluent: hexane: CH2Cl2 = 5:1) to obtain the target product intermediate C-1. LC-MS: measured value: 518.35 ([M+H]+), theoretical value: 517.16.

[0162] (2) 0.01 mol of intermediate C-1 and 0.012 mol of intermediate A-1 were added to a three-necked flask, dissolved in a mixed solvent (60 mL toluene, 30 mL ethanol), and then 1×10 -4 mol Pd(PPh3)4, 15mL of 3mol / L K2CO3 aqueous solution, heated to reflux under nitrogen protection for 12 hours. Sampling point plate, confirm that the reaction is complete. After cooling to room temperature, the reaction mixture is filtered through a diatomaceous earth pad, rinsed with chloroform, and the resulting filtrate is evaporated in vacuo. The obtained residue is purified by column chromatography on silica gel, using hexane / toluene as eluent to obtain compound 1.

[0163] The compounds in the following Examples 2 to 17 were prepared using the same method as Example 1, except that different intermediates A, intermediates B and raw materials M were used. The intermediates and raw materials used in the synthesis process are shown in Table 1 below.

[0164] Table 1

[0165]

[0166]

[0167]

[0168] Preparation of organic electroluminescent devices

[0169] The molecular structures of the materials involved in the following preparation process are shown below:

[0170]

[0171] Device Comparison Example 1

[0172] The organic electroluminescent device was prepared by following the steps below:

[0173] a) using transparent glass as a substrate, washing the anode layer 2 (Ag (100 nm)) thereon, i.e., sequentially performing alkali washing, pure water washing, drying, and then performing ultraviolet-ozone washing to remove organic residues on the surface of the anode layer;

[0174] b) on the washed anode layer 2, using a vacuum evaporation device, 10 nm thick HT-1 and P-type doped HI-1 were evaporated as a hole injection layer 3, the mass ratio of HT-1 to HI-1 was 97:3;

[0175] c) On the hole injection layer, a hole transport layer 4 is deposited by vacuum evaporation. The hole transport layer material is compound HT-1 with a thickness of 117 nm;

[0176] d) On the hole transport layer, an electron blocking layer 5 is deposited by vacuum evaporation, wherein the electron blocking layer material is EB-1 and has a thickness of 10 nm;

[0177] e) On the electron blocking layer, a light-emitting layer 6 of an OLED light-emitting device is manufactured, wherein the structure includes BH-1 used as a main material of the OLED light-emitting layer 6, BD-1 as a doping material, the doping ratio of the doping material is 3% by weight, and the thickness of the light-emitting layer is 20 nm;

[0178] f) On the light-emitting layer, HB-1 is continuously evaporated as a hole blocking layer 7, and the evaporated film thickness is 8 nm;

[0179] g) On the hole blocking layer, ET-1 and Liq were evaporated by vacuum evaporation, the mass ratio of ET-1 and Liq was 50:50, and the thickness was 30 nm. This layer served as the electron transport layer 8;

[0180] h) LiF is deposited on the electron transport layer by vacuum evaporation with a thickness of 1 nm, and this layer is the electron injection layer 9;

[0181] i) on the electron injection layer, a Mg:Ag (1:9) electrode layer is vacuum-deposited with a thickness of 16 nm, which is the cathode layer 10;

[0182] j) On the cathode layer, 70 nm of CPL-1 was vacuum-deposited as the CPL layer 11.

[0183] Device Comparative Examples 2-5 and Device Comparative Example 9 were carried out according to the method of Device Comparative Example 1, except that the organic materials in step b) / c) were replaced by organic materials shown in Table 3. Device Comparative Examples 6-8 were carried out according to the method of Device Comparative Example 1, except that the organic materials in b) / c) / g) were replaced by organic materials shown in Table 3. Device Preparation Examples 1-18 were carried out according to the method of Device Comparative Example 1, except that the organic materials in step b) / c) were replaced by organic materials shown in Table 3. Device Preparation Examples 19-24 were carried out according to the method of Device Comparative Example 1, except that the organic materials in b) / c) / g) were replaced by organic materials shown in Table 3.

[0184] Table 3

[0185]

[0186]

[0187] In the above table, taking Example 1 as an example, "1:HI-1(3%10nm)" in the second column means that the materials used for the hole injection layer are the compound 1 of the present invention and the P-type doping material HI-1, and 3% refers to the weight ratio of the P-type doping material HI-1 to the materials used for the hole injection layer: 10nm means the thickness of the layer; "1(117nm)" in the third column means that the material used is the compound 1 of the present invention, and the thickness of the layer is 117nm. The meanings in other tables can be deduced by analogy.

[0188] After the OLED light-emitting device is prepared as described above, the cathode and the anode are connected using a known driving circuit, and various properties of the device are measured.

[0189] The device performance measurement results of Examples 1-24 and Comparative Examples 1-9 are shown in Table 4.

[0190] Table 4

[0191]

[0192] Note: Voltage, current efficiency and color coordinates were tested using an IVL (current-voltage-luminance) test system (Suzhou Foster Scientific Instrument Co., Ltd.) at a current density of 10 mA / cm 2 ; The life test system is the EAS-62C OLED device life tester produced by Japan System Engineering Co., Ltd.; LT95 refers to the time taken for the device brightness to decay to 95% at a specific brightness; Index = current efficiency / CIEy.

[0193] In Table 4, the voltage represents the driving voltage of the device, that is, the device voltage. From the results of Comparative Examples 1-5, Comparative Example 9, and Device Examples 1-18 in Table 4, it can be seen that the use of the biphenylamine compounds of the present invention as hole injection and hole transport layer materials has improved device efficiency and prolonged device life due to its high carrier transport rate;

[0194] From the results of Comparative Examples 6-8 and Device Examples 19-24 in Table 4, it can be seen that the compounds of the diaromatic amine structure of the present invention are used in combination with specific electron transport layer materials. This combination effectively reduces the voltage of the device and further extends the service life of the device.

[0195] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A compound having a diarylamine structure, characterized in that: The compound structure is shown in general formula (2-1): In the general formula (2-1), R1 to R4 are independently represented by substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted furanyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted thienyl, substituted or unsubstituted benzothienyl, substituted or unsubstituted dibenzothienyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted N-phenylcarbazolyl, substituted or unsubstituted 9,9-dimethylfluorenyl, substituted or unsubstituted 9,9-diphenylfluorenyl, substituted or unsubstituted spirofluorenyl; The L1 to L4 are independently a straight chain bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, a substituted or unsubstituted terphenylene group, or a substituted or unsubstituted naphthylene group; The substituent of the "substituted or unsubstituted" group is selected from one or more of a deuterium atom, a methyl group, an ethyl group, a tert-butyl group, a phenyl group, a naphthyl group, a biphenyl group, a furyl group, a benzofuranyl group, and a dibenzofuranyl group.

2. The compound of the diarylamine structure according to claim 1, characterized in that: The compound structure is shown in general formula (3-1), general formula (3-2) or general formula (3-3): In the general formula (3-1) to the general formula (3-3), It means there is no single bond connection between the two side groups; Said R1, R2, R3, and R4 are independently represented by substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted furyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted thienyl, substituted or unsubstituted benzothienyl, substituted or unsubstituted dibenzothienyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted N-phenylcarbazolyl, substituted or unsubstituted 9,9-dimethylfluorenyl, substituted or unsubstituted 9,9-diphenylfluorenyl, substituted or unsubstituted spirofluorenyl; The L1 to L4 are independently a straight chain bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, a substituted or unsubstituted terphenylene group, or a substituted or unsubstituted naphthylene group; The substituent of the "substituted or unsubstituted" group is selected from one or more of a deuterium atom, a methyl group, an ethyl group, a tert-butyl group, a phenyl group, a naphthyl group, a biphenyl group, a furyl group, a benzofuranyl group, and a dibenzofuranyl group.

3. The compound of the diarylamine structure according to any one of claims 1 to 2, characterized in that: Said R1 to R4 are independently represented by substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted furyl, substituted or unsubstituted benzofuranyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted thienyl, substituted or unsubstituted benzothienyl, substituted or unsubstituted dibenzothienyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted N-phenylcarbazolyl; The L1 to L4 are independently a straight chain bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, a substituted or unsubstituted terphenylene group, or a substituted or unsubstituted naphthylene group; The substituent of the "substituted or unsubstituted" group is selected from one or more of a deuterium atom, a methyl group, an ethyl group, a tert-butyl group, a phenyl group, a naphthyl group, a biphenyl group, a furyl group, a benzofuranyl group, and a dibenzofuranyl group.

4. The compound of the diarylamine structure according to any one of claims 1 to 2, characterized in that: The R1 to R4 are independently represented by: substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthrenyl, substituted or unsubstituted furanyl; The L1 to L4 are independently a straight chain bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, a substituted or unsubstituted terphenylene group, or a substituted or unsubstituted naphthylene group; The substituent of the "substituted or unsubstituted" group is selected from one or more of a deuterium atom, a methyl group, an ethyl group, a tert-butyl group, a phenyl group, a naphthyl group, a biphenyl group, a furyl group, a benzofuranyl group, and a dibenzofuranyl group.

5. The compound of the diarylamine structure according to claim 1, characterized in that: The specific structure of the compound is any one of the following structures:

6. An organic electroluminescent device, which comprises an anode, a hole transport region, a light emitting region, an electron transport region and a cathode in sequence, characterized in that: The hole transport region comprises the biphenylamine structure compound according to any one of claims 1 to 5.

7. The organic electroluminescent device according to claim 6, characterized in that: The hole transport region comprises a hole injection layer, a hole transport layer and an electron blocking layer, and the hole transport layer and the hole injection layer comprise the diarylamine structural compound according to any one of claims 1 to 5.

8. The organic electroluminescent device according to claim 7, characterized in that: The hole transport layer comprises the diarylamine structure compound according to any one of claims 1 to 5, and the hole injection layer comprises the diarylamine structure compound according to any one of claims 1 to 5 and other doping materials.

9. The organic electroluminescent device according to claim 6, characterized in that: The electron transport region comprises a nitrogen heterocyclic compound represented by the following general formula (4): In the general formula (4), Ar1, Ar2, and Ar3 are independently substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C2-C 30 One of the heterocyclic groups; L is selected from a single bond, a substituted or unsubstituted C6-C 30 Arylene, substituted or unsubstituted C2-C 30 A heterocyclylene group; X1, X2, and X3 independently represent N or C-(H), and at least one of X1, X2, and X3 represents N; The substituents of the "substituted or unsubstituted" group are optionally selected from deuterium, tritium, C 1-10 Alkyl, C6-C 30 Aryl, C2-C 30 one or more of heteroaryl groups; The heteroatom is selected from one or more of an oxygen atom, a sulfur atom or a nitrogen atom.

Images