An aromatic amine compound and an organic electroluminescent device comprising the same

Abstract

The present invention discloses an aromatic amine compound and an organic electroluminescent device comprising the same. The structure of the aromatic amine compound is shown by the general formula (1): The compound of the present invention has excellent hole transport ability and exciton blocking ability. When using the organic compound of the present invention to form the light-emitting layer auxiliary layer material of the organic electroluminescent device, it can simultaneously show the effects of improving device efficiency and extending device life, especially improving device efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials, and particularly to an aromatic amine compound and an organic electroluminescent device containing the same. 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 shift of the recombination region, which is not conducive to the stability of the device. 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, it has been difficult to comprehensively improve the performance such as the efficiency and lifespan of blue light devices. Therefore, how to improve the performance of such devices is still a crucial problem and challenge faced by this field. Most of the blue light host materials used in the current market are electron-rich hosts. At low current densities, due to the preferential injection of holes, the pressure on the hole transport side is alleviated to a certain extent. As the current density increases, the amount of electron injection will be more and more, resulting in the recombination region shifting towards the hole side, and the pressure on the hole side becoming greater and greater. In order to prevent excitons from transferring to the hole side, it is required that the light-emitting auxiliary layer material can effectively block excitons and can efficiently transport holes to the light-emitting layer. Currently, most of the light-emitting auxiliary layer materials are traditional aromatic amine structures, and the side chains are selected from carbazole groups or dibenzofuran groups. The exciton resistance stability of such structures still cannot meet the requirements, and the hole mobility at high current densities still needs to be improved, so as to ensure the carrier balance in the light-emitting layer and prevent the device efficiency from decreasing and the lifespan from shortening due to insufficient holes and the recombination region shifting towards the hole transport side. Summary of the Invention

[0004] In view of the above problems existing in the prior art, the present invention provides an aromatic amine compound and an organic electroluminescent device containing the same. The aromatic amine compound of the present invention has excellent hole transport ability (especially the hole mobility at high current densities) and exciton blocking ability. When using the organic compound of the present invention to form the light-emitting auxiliary layer material of the organic electroluminescent device, the effects of improving the device efficiency and prolonging the lifespan can be simultaneously shown, especially the improvement of the device efficiency is very significant.

[0005] The technical solution of the present invention is as follows:

[0006] An aromatic amine compound, the structure of the compound is shown in the general formula (1):

[0007]

[0008] In the general formula (1), R represents one of phenyl, naphthyl, biphenylyl, terphenyl, dibenzofuranyl, benzofuranyl, furanyl, thiophenyl, benzothiophenyl, dibenzothiophenyl;

[0009] R1 represents a structure shown in the general formula (2) or the general formula (3);

[0010] R2 and R3 each independently represent a hydrogen atom or a structure shown in the general formula (2) or the general formula (3);

[0011] R4 represents a hydrogen atom or a structure shown in the general formula (2):

[0012]

[0013] In the general formula (2), A represents a hydrogen atom, a structure shown in the general formula (4) or the general formula (5); the general formula (4) and the general formula (5) are respectively fused to the main structure of the general formula (2) through a and b, b and c, or c and d;

[0014]

[0015]

[0016] In the general formula (4), X represents an oxygen atom, a sulfur atom or N(R0); R0 represents phenyl, naphthyl or biphenylyl; 30 In the general formula (3), L1 and L2 each independently represent a single bond, phenylene, naphthylene or biphenylene; Ar1 and Ar2 each independently represent a substituted or unsubstituted C6-C 30 aryl, a substituted or unsubstituted C3-C

[0017] Among R1-R4, only one represents a structure shown in the general formula (2), and only one represents a structure shown in the general formula (3);

[0018] When R1 represents a structure shown in the general formula (2), R4 represents a hydrogen atom;

[0019] The substituents for substitution are optionally selected from one or more of deuterium atom, phenyl, naphthyl, biphenylyl.

[0020] In a preferred embodiment, the structure of the compound is shown in any one of the general formulas (1-1) to (1-5):

[0021]

[0022] In general formulas (1-1) to (1-5), the meanings of R, A, L1, L2, Ar1, and Ar2 are the same as those defined above.

[0023] In a preferred embodiment, general formula (2) is represented by any one of the following structures:

[0024]

[0025]

[0026] The meaning of R0 is the same as that defined above.

[0027] In a preferred embodiment, the structure of the compound is represented by any one of general formulas (1-6) to (1-17):

[0028]

[0029] In general formulas (1-6) to (1-17), the meanings of R, X, L1, L2, Ar1, and Ar2 are the same as those defined in general formula (1).

[0030] More preferably, Ar1 and Ar2 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 terphenyl group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted pyrenyl group, a substituted or unsubstituted furyl group, a substituted or unsubstituted benzofuryl group, a substituted or unsubstituted dibenzofuryl group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted benzothienyl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dimethylfluorenyl group, a substituted or unsubstituted spirofluorene group, and a substituted or unsubstituted pyridyl group;

[0031] The substituents for substitution are selected from one or more of a deuterium atom, a phenyl group, a naphthyl group, and a biphenyl group.

[0032] Even more preferably, R is represented by a phenyl group, a naphthyl group, a biphenyl group, or a dibenzofuryl group; Ar1 and Ar2 are each independently represented by one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted dibenzofuryl group.

[0033] Even more preferably, general formula (2) is represented by any one of the following structures:

[0034]

[0035] In a preferred embodiment, the specific structure of the aromatic amine compound is any one of the following structures:

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049] 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 aromatic amine compound.

[0050] The hole transport region includes a hole injection layer, a hole transport layer, and a light-emitting layer auxiliary layer, and the light-emitting layer auxiliary layer contains the aromatic amine compound.

[0051] The electron transport region contains a nitrogen heterocyclic compound represented by the general formula (6):

[0052]

[0053] Wherein, Ar5, Ar6, and Ar7 are each independently selected from a substituted or unsubstituted C6-C 30 aryl group, a substituted or unsubstituted C3-C containing one or more heteroatoms 30 heteroaryl group;

[0054] L3 represents a single bond, a substituted or unsubstituted C6-C 30 arylene group, a substituted or unsubstituted C3-C containing one or more heteroatoms 30 heteroarylene group;

[0055] X1, X2, and X3 each independently represent N or C(H), and at least one of X1, X2, and X3 represents N;

[0056] Each of the heteroatoms is independently selected from N, O, or S;

[0057] The substituents for the substituting groups are one or more of deuterium atoms, phenyl groups, naphthyl groups, biphenyl groups, dibenzofuranyl groups, dibenzothiophenyl groups, pyridyl groups, or pyrimidinyl groups.

[0058] The present invention also provides an organic electroluminescent device, which sequentially includes an anode, a hole transport region, a light-emitting region, an electron transport region, and a cathode, and the hole transport region contains the aromatic amine compound described above.

[0059] The beneficial technical effects of the present invention are as follows:

[0060] (1) The aromatic amine compound of the present invention has more excellent exciton blocking ability, enabling excitons to be better localized in the light-emitting region, ensuring a relatively high exciton concentration in the light-emitting region, and thus improving the light-emitting efficiency.

[0061] (2) The connection mode and specific types of groups of the compound of the present application ensure the formation of energy levels with different carrier conduction within the aromatic amine molecular structure, thereby forming different carrier conduction channels. This is beneficial for the injection and conduction of carriers between materials with different energy levels, and thus beneficial for obtaining the interface stability between the compound of the present application and the adjacent layer materials, and thereby beneficial for obtaining a good driving life of the application device.

[0062] (3) Because the structural characteristics of the organic compound of the present application are beneficial for increasing the glass transition temperature of the molecule and at the same time beneficial for reducing the evaporation temperature of the molecule, that is, even if the molecular weight of the structure is relatively high, it can ensure a relatively low evaporation temperature. This excellent performance is not only beneficial for the thermal evaporation of the material and controlling the thermal decomposition rate of the material, thereby improving the stability of the material in device applications.

[0063] The organic functional materials constituting the 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, aromatic amine compounds matching 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 structure characteristic, such as triazine materials, pyridine materials, pyrazine materials, etc. or compounds containing these characteristic groups. The aromatic amine compounds of the present invention are combined with pyridine ring-based electron transport materials, making it easy for electrons and holes to obtain the best balance state, and having excellent life while having high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a cross-sectional view of the organic electroluminescent device of the present invention.

[0065] In the figure, 1 represents a substrate layer; 2 represents an anode layer; 3 represents a hole injection layer; 4 represents a hole transport layer; 5 represents a light-emitting auxiliary layer; 6 represents a light-emitting layer; 7 represents a hole blocking layer; 8 represents an electron transport layer; 9 represents an electron injection layer; 10 represents a cathode layer; 11 represents a cover layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0066] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the 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 following 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. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0067] 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 their combinations.

[0068] In the present invention, unless otherwise specified, HOMO means the highest occupied molecular orbital, and LUMO means the lowest unoccupied molecular orbital. In addition, in the present invention, the HOMO and LUMO energy levels are represented by absolute values, and the comparison between the energy levels is also a comparison of the magnitudes of their absolute values. Those skilled in the art know that the larger the absolute value of the energy level, the lower the energy of the energy level.

[0069] In the present invention, when a layer or an 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 an intermediate layer may also be present. Further, 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 one or more intermediate layers may also be present. The same reference numerals throughout the text denote the same elements.

[0070] 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 relevant structures can only exist in the stated orientation; on the contrary, if the structure can be repositioned, for example, inverted, the orientation of the structure is changed accordingly. Specifically, in the present invention, the "bottom" and "lower" sides of the 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.

[0071] 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.

[0072] In this specification, the hole characteristic refers to 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.

[0073] In this specification, the electron characteristic refers to 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.

[0074] Organic electroluminescent device

[0075] The present invention provides an organic electroluminescent device using an aromatic amine compound of general formula (1).

[0076] 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, and the hole transport region contains an aromatic amine compound of general formula (1).

[0077] Preferably, the hole transport region includes a hole injection layer, a hole transport layer, and a light-emitting layer auxiliary layer, and the light-emitting layer auxiliary layer contains an aromatic amine compound of general formula (1).

[0078] Preferred embodiment, the electron transport region contains an azacyclic compound represented by the general formula (6):

[0079] The organic electroluminescent device of the present invention can be a bottom-emitting organic electroluminescent device, a top-emitting organic electroluminescent device, and a stacked organic electroluminescent device, and there is no specific limitation thereto.

[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; 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.

[0081] Anode

[0082] 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 not limited thereto. The thickness of the anode depends on the material used, and is usually 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.

[0083] Cathode

[0084] 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 a combination thereof; multilayer structure materials 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 usually 10-50 nm, preferably 15-20 nm.

[0085] Light-emitting region

[0086] In the present invention, the light-emitting region can be disposed between the anode and the cathode, and can include at least one host material and at least one guest material. 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 can be, for example, a thiazole derivative, a benzimidazole derivative, a polydialkylfluorene derivative, or 4,4'-bis(9-carbazolyl)biphenyl (CBP). The host material can use a compound containing an anthracene group. The guest material can 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 contains one or two host material compounds.

[0088] 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.

[0089] 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:

[0090]

[0091]

[0092] In the present invention, the light-emitting region can 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:

[0093]

[0094] 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.

[0095] The thickness of the light-emitting region can be 10 - 50 nm, preferably 15 - 30 nm, but the thickness is not limited to this range.

[0096] Hole transport region

[0097] In the organic electroluminescent device of the present invention, a hole transport region is disposed between the anode and the light-emitting region, and it includes a hole injection layer, a hole transport layer, and a light-emitting auxiliary layer.

[0098] Hole injection layer

[0099] 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, and only then is it expected to achieve 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.

[0100] Preferably, specific examples of the host organic material include: metal porphyrins, oligothiophenes, organic materials of arylamines, hexanitrile hexaazatriphenylene, 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 arylamines.

[0101] 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.

[0102] 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:

[0103] 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.

[0104] In a preferred embodiment of the present invention, the hole injection layer is a mixed film layer of an arylamine compound and a P-type doping material, and the arylamine compound is an aromatic amine compound of 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, the hole transport layer may be disposed above the hole injection layer. The hole transport material is a suitable material with 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: arylamine organic materials, conductive polymers, block copolymers having both a conjugated portion and a non-conjugated portion, etc., but are not limited thereto. In a preferred embodiment, the hole transport layer contains the same aromatic amine compound as the hole injection layer.

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

[0109] Light-emitting auxiliary layer

[0110] In the organic electroluminescent device of the present invention, the light-emitting auxiliary 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 light-emitting auxiliary layer is provided in contact with 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 light-emitting auxiliary layer material is selected from the aromatic amine compounds represented by the general formula (1). The thickness of the light-emitting auxiliary layer may be 5-20 nm, preferably 8-15 nm, but the thickness is not limited to this range.

[0111] Electron transport region

[0112] 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.

[0113] Electron injection layer

[0114] 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, such 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 may be 0.1-5 nm, preferably 0.5-3 nm and more preferably 0.8-1.5 nm, but the thickness is not limited to this range.

[0115] Electron transport layer

[0116] 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, triazine derivatives such as 2,4-bis(9,9-dimethyl-9H-fluoren-2-yl)-6-(naphthalen-2-yl)-1,3,5-triazine (CAS No.: 1459162-51-6), imidazole derivatives such as 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), oxadiazole derivatives, etc.

[0117] In the preferred organic electroluminescent device of the present invention, the electron transport layer contains an azacyclic compound of general formula (6):

[0118]

[0119] wherein Ar5, Ar6, and Ar7 are each independently selected from substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C3-C containing one or more heteroatoms 30 heteroaryl;

[0120] L3 represents a single bond, substituted or unsubstituted C6-C 30 arylene, substituted or unsubstituted C3-C containing one or more heteroatoms 30 heteroarylene;

[0121] X1, X2, and X3 each independently represent N or C(H), and at least one of X1, X2, and X3 represents N;

[0122] Each of the heteroatoms is independently selected from N, O, or S;

[0123] The substituents for the substitution groups are one or more of deuterium atoms, phenyl, naphthyl, biphenyl, dibenzofuranyl, dibenzothiophenyl, pyridyl, or pyrimidinyl.

[0124] Preferably, Ar5, Ar6, and Ar7 each independently represent one of 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, and a substituted or unsubstituted quinolinyl group;

[0125] L3 represents a single bond, a phenylene group, a biphenylene group, or a naphthylene group;

[0126] 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, and a pyrimidinyl group

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

[0128]

[0129]

[0130] In a more preferred embodiment of the present invention, the electron transport layer comprises any one of the compounds selected from the following:

[0131]

[0132] In a preferred embodiment of the present invention, in addition to the compound of general formula (6), the electron transport layer further includes 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 general formula (6) and one of the other compounds conventionally used in the electron transport layer (preferably LiQ).

[0133] The hole injection and transport rates in the hole transport region containing the aromatic amine 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 aromatic amine compound of the present invention can be better matched with the electron injection and transport rates in the electron transport region containing the azacyclic compound of general formula (6).

[0134] Therefore, in a particular embodiment of the present invention, using one or more of the azacyclic compounds of general formula (6) or an electron transport region composed thereof, in combination with the hole transport region containing the aromatic amine compound of the present invention, relatively better technical effects are achieved.

[0135] 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.

[0136] Cover layer

[0137] To improve the light extraction efficiency of the organic electroluminescent device, a light extraction layer (i.e., the CPL layer, also known as the cover layer) can also be added to 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 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.

[0138] The organic electroluminescent device of the present invention may also 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.

[0139] The present invention also relates to a method for preparing an organic electroluminescent device, which includes successively 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 on a substrate, and optionally a cover layer. In this regard, methods such as vacuum deposition, vacuum evaporation, spin coating, casting, LB method, inkjet printing, laser printing, or LITI can be used, but are not limited thereto. In the present invention, vacuum evaporation is preferably used to form the respective layers. Those skilled in the art can conventionally select the respective process conditions in the vacuum evaporation method according to actual needs.

[0140] In addition, it should be noted that the materials used in the present invention for forming the respective layers can be formed into a film alone and used as a single layer, or can be formed into a film after being mixed with other materials and used as a single layer, and can also be a stacked structure between layers formed into a film alone, a stacked structure between layers formed into a film after being mixed, or a stacked structure of a layer formed into a film alone and a layer formed into a film after being mixed.

[0141] Preparation examples

[0142] Unless otherwise specified, all kinds of 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.

[0143] Synthesis of intermediates

[0144] Synthesis of intermediate K-4:

[0145]

[0146] In a three-necked flask, under nitrogen protection, 0.022 mol of raw material A-2, 0.02 mol of raw material D-10, and 250 mL of toluene were added and stirred to mix. Then, 1.1×10 -4 mol of Pd2(dba)3, 1.1×10 -4 mol of P(t-Bu)3, and 0.05 mol of sodium tert-butoxide were added. The mixture was heated to 110 °C and refluxed for 21 hours. It was naturally cooled to room temperature, filtered, and the filtrate was rotary evaporated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: hexane:CH2Cl2 = 5:1) to obtain the target product intermediate M-1. LC-MS: Measured value: 406.28 ([M+H] + ), theoretical value: 405.13.

[0147] In a three-necked flask, under nitrogen protection, 3 mmol of intermediate M-1, 6 mmol of bis(pinacolato)diboron, 9 mmol of potassium acetate, 0.6 mmol of S-phos, and 0.12 mmol of Pd2(dba)3 were added to 150 mL of dioxane. The mixture was refluxed for 8 h, and the reaction system was cooled to room temperature. The reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous magnesium sulfate, and distilled under reduced pressure. It was purified by silica gel column chromatography using n-heptane / ethyl acetate (9:1) as the eluent to obtain intermediate K-4. LC-MS: Measured value: 498.32 ([M+H] + ), exact mass: 497.25.

[0148] Synthesis of intermediate K-5:

[0149]

[0150] The synthesis method of intermediate M-2 is the same as that of intermediate M-1, except that raw material D-9 is used to replace raw material D-10 to obtain intermediate M-2. LC-MS: Measured value: 522.34 ([M+H] + ), theoretical value: 521.15.

[0151] The synthesis method of intermediate K-5 is the same as that of intermediate K-4, except that intermediate M-2 is used to replace intermediate M-1 to obtain intermediate K-5. LC-MS: Measured value: 614.36 ([M+H] + ), theoretical value: 613.28.

[0152] Preparation of examples

[0153] Example 1: Synthesis of compound 2

[0154]

[0155] (1) Add 12 mmol of raw material A-1 and 10 mmol of raw material B-1 to a three-necked flask, dissolve with a mixed solvent (70 mL of toluene, 35 mL of ethanol), then add 0.1 mmol of Pd(PPh3)4 and 15 mL of a 3 mol / L aqueous solution of K2CO3, and heat under reflux for 12 hours under nitrogen protection. Take a sample and confirm that the reaction is complete. After cooling to room temperature, filter the reaction mixture through a diatomaceous earth pad, rinse with chloroform, and evaporate the resulting filtrate in vacuo. Purify the obtained residue by column chromatography on silica gel using hexane / toluene as an eluent to obtain intermediate P-1. LC-MS: Measured value: 267.04 ([M+H] + ), exact mass: 265.95.

[0156] (2) In a three-necked flask, under nitrogen protection, add 12 mmol of intermediate P-1, 10 mmol of raw material C-1, and 150 mL of toluene, stir and mix, then add 0.05 mmol of Pd2(dba)3, 0.05 mmol of tri-tert-butylphosphine, and 30 mmol of sodium tert-butoxide, heat to 105°C, reflux for 20 hours, take a sample, and it shows that there is no raw material C-1 left, and the reaction is complete; cool naturally to room temperature, filter, and evaporate the filtrate until there is no fraction, and pass it through a neutral silica gel column to obtain intermediate Q-1. LC-MS: Measured value: 444.18 ([M+H] + ), exact mass: 443.11.

[0157] (3) In a three-necked flask, under nitrogen protection, 3 mmol of raw material D-1, 6 mmol of bipyraclostrobin, 9 mmol of potassium acetate, 0.6 mmol of S-phos, and 0.12 mmol of Pd2(dba)3 were added to 150 mL of dioxane, and the mixture was refluxed for 8 h. The reaction system was cooled to room temperature, and the reaction mixture was diluted with ethyl acetate, washed with water, dried over anhydrous magnesium sulfate, and distilled under reduced pressure. The mixture was purified by silica gel column chromatography using n-heptane / ethyl acetate (9:1) as the eluent to obtain intermediate K-1. LC-MS: Measured value: 574.35 ([M+H] + ), exact mass: 573.28.

[0158] (4) Add 10 mmol of intermediate Q-1 and 12 mmol of intermediate K-1 into a three-necked flask, dissolve them with a mixed solvent (70 mL of toluene, 35 mL of ethanol), then add 0.1 mmol of Pd(PPh3)4 and 15 mL of 3 mol / L aqueous K2CO3 solution. Heat under reflux for 12 hours under nitrogen protection. Take a sample for TLC to confirm the completion of the reaction. After cooling to room temperature, filter the reaction mixture through a celite pad, wash with chloroform, and evaporate the obtained filtrate under vacuum. Purify the obtained residue by column chromatography on silica gel using hexane / toluene as the eluent to obtain Compound 2.

[0159] The compounds in the following Examples 2 to 20 were prepared using the same method as in Example 1, except that different starting materials A, B, C and intermediate K were used. The starting materials and intermediates used in the synthesis are shown in Table 1 below.

[0160] Table 1

[0161]

[0162]

[0163]

[0164] The characterization data of the compounds in each example herein are shown in Table 2:

[0165] Table 2

[0166]

[0167] Detection method

[0168] Glass transition temperature Tg: Measured by differential scanning calorimetry (DSC, Netzsch DSC204F1 differential scanning calorimeter), heating rate 10 °C / min.

[0169] HOMO energy level: Tested by an ionization energy test system (IPS3), the test is in a vacuum environment.

[0170] 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 film of the material and the rising side of the first absorption peak, make a tangent line, and calculate with the intersection value of the tangent line and the baseline.

[0171] Hole mobility: The material is made into a single-charge device and measured by the space charge (induced) limited current method (SCLC).

[0172] Triplet energy level T1: Tested by a Horiba Fluorolog-3 series fluorescence spectrometer, the test conditions for the material are 2×10-5 Toluene solution with a concentration of

[0173] See Table 3 for the specific physical property test results.

[0174] Table 3

[0175]

[0176] As can be seen from the data in Table 3 above, the compound of the present invention has a suitable HOMO energy level, a relatively high hole mobility, and a relatively wide band gap (Eg), and can be used to realize an organic electroluminescent device with high efficiency and long lifetime.

[0177] Preparation of organic electroluminescent device

[0178] The application effects of the OLED materials synthesized by the present invention in the device are described in detail below through Device Examples 1-25 and Device Comparative Examples 1-5. Compared with Device Comparative Example 1, the manufacturing processes of the devices in Device Examples 1-25 and Device Comparative Examples 2-5 are exactly the same, and the same substrate materials and electrode materials are used, and the film thicknesses of the electrode materials are also kept consistent. The difference is that the functional layer materials in the devices are replaced.

[0179] The molecular structural formulas of the materials involved in the following preparation process are shown as follows:

[0180]

[0181]

[0182] Device Comparative Example 1

[0183] Prepare an organic electroluminescent device according to the following steps:

[0184] As Figure 1As shown, the transparent substrate layer 1 is a transparent PI film. 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-mentioned 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 light-emitting auxiliary layer 5. After the evaporation of the above light-emitting auxiliary layer material, 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 in 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, HB-1 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 with a mass ratio of ET-1 and Liq of 1:1, and the vacuum evaporation film thickness of this material is 30 nm. 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. 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. 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 CPL-1 is vacuum-evaporated as the cover layer 11.

[0185] Device Comparative Examples 2 - 5

[0186] It is carried out according to the method of Device Comparative Example 1, except that the organic materials in the light-emitting auxiliary layer are respectively replaced with the organic materials shown in Table 4.

[0187] Device Examples 1 - 20

[0188] It is carried out according to the method of Device Comparative Example 1, except that the organic materials in the light-emitting auxiliary layer are respectively replaced with the organic materials shown in Table 4.

[0189] Device Examples 21 - 25

[0190] It is carried out according to the method of Device Comparative Example 1, except that the organic materials in the light-emitting auxiliary layer and the organic materials in the electron transport layer are respectively replaced with the organic materials shown in Table 4.

[0191] Table 4

[0192]

[0193]

[0194] Taking the row where Example 1 is located in the above table as an example, "P-1:HT-1 = 3:97 10nm" in the second column of the table indicates that the materials used for the hole injection layer are the P-type doped material P-1 and the compound HT-1. 3:97 refers to the weight ratio of the P-type doped material P-1 and the compound HT-1 being 3:97, and 10nm represents the thickness of this layer; "210nm" in the fourth column of the table indicates that the material used for the electron blocking layer is compound 2, and the thickness of this layer is 10nm. And so on for the meanings of the materials used for other functional layers in the table.

[0195] After preparing the OLED light-emitting device as described above, a known driving circuit is used to connect the cathode and the anode, and various performances of the device are measured.

[0196] The measurement performance results of the devices of Examples 1-25 and Comparative Examples 1-5 are shown in Table 5.

[0197] Table 5

[0198]

[0199] Note: In this article, LT95 refers to the time used when starting the test at a brightness of 3000 nits until the brightness of the device decays to 95% of the brightness at the start of the test; the voltage, current efficiency, and color coordinates are measured using an IVL (current-voltage-brightness) test system (Suzhou Fosida Scientific Instruments Co., Ltd.) under the condition of a current density of 10 mA / cm 2 ; the lifetime test uses an EAS-62C type OLED lifetime test system of System Science Co., Ltd. of Japan.

[0200] From the results of Comparative Examples 1-5 and Examples 1-25 in Table 5, it can be seen that by using the aromatic amine compound of the present invention as the material for the light-emitting auxiliary layer, due to its high carrier transport rate and exciton blocking ability, the efficiency and lifetime of the device are effectively improved, especially the efficiency of the device is unexpectedly significantly improved (while maintaining a certain lifetime advantage).

Claims

1. An aromatic amine compound, characterized in that, The structure of the said compound is shown as any one of general formula (1-1) to general formula (1-2): In general formula (1-1) to general formula (1-2), the said R represents one of phenyl, naphthyl, biphenylyl, dibenzofuranyl, dibenzothiophenyl; The said A represents a hydrogen atom, the structure shown by general formula (4) or general formula (5); General formula (4) and general formula (5) are respectively condensed with the carbazolyl group through a and b, b and c or c and d; In general formula (4), the said X represents an oxygen atom, a sulfur atom or N(R0); The said R0 represents phenyl, naphthyl or biphenylyl; The said L1 and L2 respectively independently represent a single bond, phenylene, naphthylene or biphenylene; The said Ar1 and Ar2 respectively independently represent one of substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenylyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted dimethylfluorenyl; The substituents for substitution are optionally selected from one or more of deuterium atom, phenyl, naphthyl.

2. The aromatic amine compound according to claim 1, characterized in that, The said is represented as any one of the following structures: The meaning of the said R0 is the same as the definition in claim 1.

3. The aromatic amine compound according to claim 1, wherein The said Ar1 and Ar2 respectively independently represent one of substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenylyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl; The substituents for substitution are selected from one or more of deuterium atom, phenyl, naphthyl.

4. The aromatic amine compound according to claim 1, characterized in that, The said R represents phenyl, naphthyl, biphenylyl, dibenzofuranyl; The said Ar1 and Ar2 respectively independently represent one of substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted dibenzofuranyl.

5. The aromatic amine compound according to claim 1, characterized in that, The is represented as any one of the following structures:

6. The aromatic amine 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 comprising, in sequence, an anode, a hole transport region, a light emitting region, an electron transport region and a cathode, characterized in that, The said hole transport region contains the aromatic amine compound described in any one of claims 1-6.

8. The organic electroluminescent device according to claim 7, wherein The said hole transport region includes a hole injection layer, a hole transport layer and a light-emitting layer auxiliary layer, and the said light-emitting layer auxiliary layer contains the aromatic amine compound described in any one of claims 1-6.

9. The organic electroluminescent device according to claim 7, wherein, The said electron transport region contains the azacyclic compound shown by general formula (6): Among them, Ar5, Ar6, and Ar7 are each independently selected from substituted or unsubstituted C6-C 30 aryl, substituted or unsubstituted C3-C containing one or more heteroatoms 30 heteroaryl; L3 represents a single bond, a substituted or unsubstituted C6-C 30 arylene, a substituted or unsubstituted C3-C containing one or more heteroatoms 30 heteroarylene; X1, X2, X3 independently represent N or C(H) with respect to each other, and at least one of X1, X2, X3 represents N; The said heteroatoms are independently selected from N, O or S; The substituents for the substitution group are one or more of deuterium atom, phenyl, naphthyl, biphenylyl, dibenzofuranyl, dibenzothiophenyl, pyridyl or pyrimidinyl.

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