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 transporting ability and exciton blocking ability. When using the aromatic amine compound of the present invention to form the light-emitting layer auxiliary layer material of the organic electroluminescent device, the effects of improving device efficiency and extending device life can be simultaneously shown, 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 comprising 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. In the existing organic electroluminescent devices, the injection and transport properties of the hole injection layer material and the hole transport layer material used are relatively weak, and the hole injection and transport rates do not match the electron injection and transport rates, resulting in a large offset of the recombination region, which is not conducive to the stability of the device. Therefore, how to adjust the balance between holes and electrons and adjust the recombination region has always been an important topic in this field.

[0003] Blue organic electroluminescent devices have always been the weak link in the development of full-color OLEDs. So far, the performance such as efficiency and lifespan of blue light devices has been difficult to be comprehensively improved. Therefore, how to improve the performance of such devices is still a crucial problem and challenge faced in this field. Currently, most of the blue light host materials used in the 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 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 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 recombination region from shifting towards the hole transport side due to insufficient holes, resulting in a decrease in device efficiency and a shortening of lifespan. Summary of the Invention

[0004] In view of the above problems existing in the prior art, the applicant of the present invention provides an aromatic amine compound. The organic 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 aromatic amine compound of the present invention to form the light-emitting auxiliary layer material of an organic electroluminescent device, the effects of improving device efficiency and extending lifespan can be simultaneously shown, especially the improvement of 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), Ar1 and Ar2 each independently represent a substituted or unsubstituted C 6-30 aryl group, a substituted or unsubstituted 5- to 30-membered heteroaryl group;

[0009] R1 represents a structure shown in the general formula (2), and the general formula (2) is fused to the general formula (1) at the site a and b, site b and c, or site c and d through the * site;

[0010]

[0011] L, L1, L2, and L3 shown respectively independently represent a single bond, a phenylene group, a naphthylene group, or a biphenylene group;

[0012] In the general formula (2), X represents an oxygen atom, a sulfur atom, or N(R); R represents a phenyl group, a naphthyl group, or a biphenyl group;

[0013] The substituents of the "substituted or unsubstituted" group are 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 benzofuranyl group, a furanyl group, a thiophenyl group, a benzothiophenyl group, a dibenzothiophenyl group, and a dibenzofuranyl group.

[0014] In a preferred embodiment, the structure of the compound is shown in any one of the general formulas (1-1) to (1-6):

[0015]

[0016] In the general formulas (1-1) to (1-6), the definitions of Ar1, Ar2, L, L1, L2, L3, and X are the same as those defined above.

[0017] In a preferred embodiment, the structure of the compound is shown in any one of the general formulas (3-1) to (3-4):

[0018]

[0019] In the general formulas (3-1) to (3-4), Ar1 and Ar2 each independently represent a substituted or unsubstituted C 6-30 aryl group, a substituted or unsubstituted 5- to 30-membered heteroaryl group;

[0020] R1 represents a structure shown in the general formula (2), and the general formula (2) is fused to the general formulas (3-1) to (3-4) at the site a and b, site b and c, or site c and d through the * site;

[0021]

[0022] L2 and L3 shown respectively independently represent a single bond, a phenylene group, a naphthylene group or a biphenylene group;

[0023] In general formula (2), X represents an oxygen atom, a sulfur atom or N(R); R represents a phenyl group, a naphthyl group or a biphenyl group;

[0024] The substituents of the "substituted or unsubstituted" group are 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 benzofuranyl group, a furanyl group, a thiophenyl group, a benzothiophenyl group, a dibenzothiophenyl group, and a dibenzofuranyl group.

[0025] Preferably, X represents an oxygen atom; L represents a single bond; L1 represents a phenylene group.

[0026] More preferably, X represents an oxygen atom; L represents a phenylene group; L1 represents a single bond.

[0027] More preferably, X represents an oxygen atom, and general formula (2) is annelated to general formula (1) at site b and c or site c and d through the * site.

[0028] Even more preferably, Ar1 and Ar2 respectively independently represent one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted furanyl group, a substituted or unsubstituted thiophenyl group, a substituted or unsubstituted benzothiophenyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted benzofuranyl group, a substituted or unsubstituted spirofluorene group, a substituted or unsubstituted diphenylfluorene group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[a]phenanthryl group;

[0029] The substituents of the "substituted or unsubstituted" group are 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 benzofuranyl group, a furanyl group, a thiophenyl group, a benzothiophenyl group, a dibenzothiophenyl group, and a dibenzofuranyl group.

[0030] In a preferred embodiment, the specific structure of the aromatic amine compound is any one of the following structures:

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040] 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 described above.

[0041] In a preferred embodiment, 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 described above.

[0042] In a preferred embodiment, the electron transport region contains a nitrogen heterocyclic compound represented by the general formula (3):

[0043]

[0044] Wherein, Ar5, Ar6, and Ar7 are each independently selected from a substituted or unsubstituted C 6-30 aryl, a substituted or unsubstituted C containing one or more heteroatoms 5-30 heteroaryl;

[0045] L3 represents a single bond, a substituted or unsubstituted C 6-30 arylene, a substituted or unsubstituted C containing one or more heteroatoms 5-30 heterocyclylene; X1, X2, and X3 each independently represent N or CH, and at least one of X1, X2, and X3 represents N; the heteroatom is selected from N, O, or S; the substituents for substituting the "substituted or unsubstituted" group are one or more of a deuterium atom, a phenyl group, a naphthyl group, a biphenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a pyridyl group, or a pyrimidinyl group.

[0046] The beneficial technical effects of the present invention are as follows:

[0047] (1) For the aromatic amine compound of the present invention, at least one of the carbazole-fused ring group, the arylamine group and the bridging group belongs to the ortho-linkage mode. Since the carbazole group adopts the fused-ring mode to increase the stability of the carbazole group, the compound of the present invention application has more excellent exciton blocking ability, so that excitons are better localized in the light-emitting region, ensuring a higher exciton concentration in the light-emitting region, and thus improving the light-emitting efficiency.

[0048] Compared with the prior art, the present invention application modifies the carbazole group by annelation and improves the connecting group on the amino group. Through these improvements, the compounds of the present invention application have more excellent exciton blocking ability and hole mobility at high current density. When applied to devices, while improving the device efficiency, they have excellent device lifetime.

[0049] (2) Also, due to the stable structure of the compounds of the present invention application, when the hole injection becomes stronger at high current density, the holes can still be conducted to the light-emitting layer through different carrier conduction channels, ensuring the hole concentration at high current density, and thus improving the light-emitting efficiency of the device.

[0050] (3) Because the structural characteristics of the organic compounds of the present invention application are beneficial to increasing the glass transition temperature of the molecule and are also beneficial to reducing the evaporation temperature of the molecule. That is to say, even if the molecular weight of the structure is relatively high, it can ensure a relatively low evaporation temperature. This excellent property is not only beneficial to the thermal evaporation of the material and controlling the thermal decomposition rate of the material, but also improves the stability of the material in device applications.

[0051] Moreover, for the arylamine molecular structural formula with the characteristics of the present invention, in addition to the connection mode between the arylamine group and the bridging group, the optimization of the ligands connected to the arylamine is beneficial to further improving the performance of the material. Selecting groups such as phenyl, naphthyl, dibenzofuranyl, phenanthrene, etc. is more beneficial to improving the stability and mobility of the material, and is also beneficial to the precise regulation of the HOMO energy level of the material, and thus obtaining good device application effects of the material.

[0052] The organic functional materials constituting the OLED device not only include hole injection and conduction materials, but also include electron injection and conduction materials and light-emitting layer materials. Good device application effects require good carrier balance as a guarantee. Therefore, in order to obtain the best device application effects, the 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 inventor, the electron-type materials are preferably materials containing the structural characteristics of azabenzene, such as triazine materials, pyridine materials, pyrazine materials, etc. or compounds containing these characteristic groups. The aromatic amine compounds of the present invention, through combination with azabenzene ring-based electron transport materials, make it easy for electrons and holes to obtain the best balance state, and have excellent lifetime while having high efficiency. Brief Description of the Drawings

[0053] Figure 1 It is a cross-sectional view of the organic electroluminescent device of the present invention.

[0054] In the figure, 1 represents the substrate layer; 2 represents the anode layer; 3 represents the hole injection layer; 4 represents the hole transport layer; 5 represents the light-emitting auxiliary layer; 6 represents the light-emitting layer; 7 represents the hole blocking layer; 8 represents the electron transport layer; 9 represents the electron injection layer; 10 represents the cathode layer; 11 represents the cover layer. Detailed implementation manners

[0055] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts 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 shall fall within the protection scope of the present invention.

[0056] It should be noted that the terms used herein are only for describing the specific implementation manners 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.

[0057] 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 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.

[0058] In the present invention, when a layer or element is referred to as being "on" another layer or substrate, the layer or element can be directly on the other layer or substrate, or there can also be an intermediate layer. In addition, it will also be understood that when a layer is referred to as being "between" two layers, the layer can be the only layer between the two layers, or there can also be one or more intermediate layers. The same reference numerals throughout the text represent the same elements.

[0059] In the present invention, when describing electrodes, organic electroluminescent devices, and other structures, terms indicating orientation such as "upper", "lower", "top", and "bottom" only represent the orientation in a specific state, and do not mean that the related 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 will change 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.

[0060] 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.

[0061] 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. The holes formed in the anode are easily injected into the light-emitting layer and transported in the light-emitting layer.

[0062] 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. The electrons formed in the cathode are easily injected into the light-emitting layer and transported in the light-emitting layer.

[0063] Organic electroluminescent device

[0064] The present invention provides an organic electroluminescent device using an aromatic amine compound represented by the general formula (1).

[0065] 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 represented by the general formula (1).

[0066] 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 represented by the general formula (1).

[0067] Preferably, the electron transport region contains a nitrogen heterocyclic compound represented by the general formula (3):

[0068] The organic electroluminescent device of the present invention can be a bottom-emitting organic electroluminescent device, a top-emitting organic electroluminescent device, or a stacked organic electroluminescent device, and no specific limitation is made thereto.

[0069] 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 smoothness, and water resistances. Depending on the properties of the substrate, their usage directions are different. In the present invention, a transparent substrate is preferably used. The thickness of the substrate is not particularly limited.

[0070] Anode

[0071] 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-dioxythiophene)), and polyaniline, but not limited thereto. The thickness of the anode depends on the material used, and is generally 50 - 500 nm, preferably 70 - 300 nm, and more preferably 100 - 200 nm. In the present invention, a combination of a metal and a metal oxide, ITO and Ag, is preferably used.

[0072] Cathode

[0073] The cathode can be made of a conductor having a relatively low work function to assist electron injection, and can be, for example, a metal or an alloy thereof such as magnesium, calcium, sodium, potassium, titanium, indium, aluminum, silver, tin, and combinations thereof; multilayer structure materials such as LiF / Al, Li2O / Al, and BaF2 / Ca, but not limited thereto. The thickness of the cathode depends on the material used, and is generally 10 - 50 nm, preferably 15 - 20 nm.

[0074] Light-emitting region

[0075] 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, 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.

[0076] In a preferred embodiment of the present invention, the light-emitting region contains one or two host material compounds.

[0077] 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.

[0078] In a preferred embodiment of the present invention, the host material of the light-emitting region used is selected from one or more of the following compounds BH-1 - BH-11:

[0079]

[0080] In the present invention, the light-emitting region may contain a phosphorescent or fluorescent guest material to improve the fluorescence or phosphorescent properties 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 of the light-emitting film layer used is selected from one of the following compounds BD-1 to BD-10:

[0081]

[0082] 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.

[0083] 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.

[0084] Hole transport region

[0085] In the organic electroluminescent device of the present invention, the 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.

[0086] Hole injection layer

[0087] The hole injection material used in the hole injection layer (also known 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, so as to be expected to achieve the occurrence of the 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.

[0088] 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.

[0089] Preferably, the P-type doping material is a compound with charge conductivity selected from the following: quinone derivatives or metal oxides, such as tungsten oxide and molybdenum oxide, but not limited thereto.

[0090] 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:

[0091] 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.

[0092] 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.

[0093] The thickness of the hole injection layer of the present invention can be 5 - 20 nm, preferably 8 - 15 nm, but the thickness is not limited to this range.

[0094] Hole transport layer

[0095] 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 into the light-emitting layer. Specific examples thereof include, but are not limited to, arylamine organic materials, conductive polymers, block copolymers having both a conjugated portion and a non-conjugated portion, etc. In a preferred embodiment, the hole transport layer contains the same arylamine organic compound as the hole injection layer.

[0096] 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.

[0097] Light-emitting auxiliary layer

[0098] In the organic electroluminescent device of the present invention, a 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.

[0099] Electron transport region

[0100] In the organic electroluminescent device of the present invention, an electron transport region is disposed between the light-emitting region and the cathode, which includes a hole blocking layer, an electron transport layer and an electron injection layer, but is not limited thereto.

[0101] Electron injection layer

[0102] 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.

[0103] Electron transport layer

[0104] The electron transport layer can be disposed above the light-emitting film layer or, if present, the hole blocking layer. The material of the electron transport layer 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 preferably used. As the electron transport layer of the organic electroluminescent device of the present invention, the 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 derivative compounds 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.

[0105] In the preferred organic electroluminescent device of the present invention, the electron transport layer contains an azacyclic compound represented by the general formula (3):

[0106]

[0107] Wherein, Ar5, Ar6, and Ar7 are each independently selected from a substituted or unsubstituted C 6-30 aryl, a substituted or unsubstituted C containing one or more heteroatoms 5-30 heteroaryl; C 6-30 aryl, a substituted or unsubstituted 5-30 membered heteroaryl;

[0108] L3 represents a single bond, a substituted or unsubstituted C 6-30 arylene, a substituted or unsubstituted C containing one or more heteroatoms 5-30 heterocyclene; X1, X2, and X3 each independently represent N or CH, and at least one of X1, X2, and X3 represents N; the heteroatom is selected from N, O, or S; the substituents for substituting the "substituted or unsubstituted" group are one or more of deuterium atom, phenyl, naphthyl, biphenyl, dibenzofuranyl, dibenzothiophenyl, pyridyl, or pyrimidinyl.

[0109] In a preferred embodiment, Ar5, Ar6, and Ar7 each independently represent a substituted or unsubstituted phenyl, a substituted or unsubstituted biphenyl, a substituted or unsubstituted naphthyl, a substituted or unsubstituted dibenzofuranyl, a substituted or unsubstituted pyridyl, a substituted or unsubstituted pyrimidinyl, a substituted or unsubstituted dibenzothiophene, or a substituted or unsubstituted quinolinyl;

[0110] L3 represents a single bond, phenylene, biphenylene, or naphthylene;

[0111] The substituents for the substituting groups are one or two of deuterium atom, phenyl group, naphthyl group, biphenyl group, dibenzofuranyl group, dibenzothiophenyl group, pyridyl group, pyrimidinyl group

[0112] In a preferred embodiment of the present invention, the electron transport layer comprises any one of the compounds selected from the following:

[0113]

[0114] In a more preferred embodiment of the present invention, the electron transport layer comprises any one of the compounds selected from the following:

[0115]

[0116] In a preferred embodiment of the present invention, in addition to the compound represented by the general formula (3), 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 the general formula (3) and one of the other compounds conventionally used in the electron transport layer (preferably LiQ).

[0117] The hole injection and transport rates of the hole transport region containing the arylamine 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 arylamine 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 the general formula (3).

[0118] Therefore, in a particular embodiment of the present invention, using one or more of the nitrogen heterocyclic derivatives of the general formula (3) or an electron transport region composed of the same, in combination with the hole transport region containing the arylamine compound of the present invention, relatively better technical effects are achieved.

[0119] 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.

[0120] Covering layer

[0121] To improve the light extraction efficiency of the organic electroluminescent device, a light extraction layer (i.e., the CPL layer, also referred to as the cover layer) can also be added on the cathode of the device. According to the principles of optical absorption and refraction, the refractive index of the CPL cover layer material should be as high as possible, and the light absorption coefficient should be as small as possible. Any material 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 generally 5 - 300 nm, preferably 20 - 100 nm and more preferably 40 - 80 nm.

[0122] 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.

[0123] Hereinafter, an organic electroluminescent device according to an embodiment of the present invention will be described.

[0124] In the drawings, for clarity, the thicknesses of layers, films, substrates, regions, etc. are enlarged. Throughout the specification, the same reference numerals denote the same elements. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or there can also be intervening elements. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements.

[0125] The present invention also relates to a method for manufacturing 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, the 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 each of the layers. Those skilled in the art can conventionally select each process condition in the vacuum evaporation method according to actual needs.

[0126] In addition, it should be noted that the materials used in the present invention for forming each layer can be formed into a film alone and used as a single layer, can also 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 between a layer formed into a film alone and a layer formed into a film after being mixed.

[0127] Preparation Examples

[0128] Example 1: Synthesis of Compound 2

[0129]

[0130]

[0131] In a three-necked flask, under nitrogen protection, add 0.01 mol of raw material A-1, 0.012 mol of raw material B-1, and 150 ml of toluene, stir and mix, then add 5×10 -5 mol Pd2(dba)3,5×10 -5 mol tri-tert-butylphosphine, 0.03 mol sodium tert-butoxide, heated to 105°C, refluxed for 24 hours, sampled the plate, showed no raw material B-1 remaining, the reaction was complete; cooled naturally to room temperature, filtered, the filtrate was evaporated until there was no fraction, passed through a neutral silica gel column, and the intermediate P-1 was obtained. Elemental analysis structure (molecular formula C 24 H 14 BrNO): theoretical value: C, 69.92; H, 3.42; N, 3.40; Br, 19.38; test value: C, 69.85; H, 3.46; N, 3.43; Br, 19.41. LC-MS: found value: 412.31 ([M+H] + ); exact mass: 411.03.

[0132] In a three-necked flask, under nitrogen protection, add 0.01 mol of raw material C-1, 0.012 mol of raw material D-1, and 150 ml of toluene, stir and mix, then add 5×10 -5 mol Pd2(dba)3,5×10 -5 mol tri-tert-butylphosphine, 0.03 mol sodium tert-butoxide, heated to 105°C, refluxed for 20 hours, sampled, and the plate showed no residual raw material D-1, indicating complete reaction; cooled naturally to room temperature, filtered, and the filtrate was evaporated until there was no fraction, and passed through a neutral silica gel column to obtain the intermediate M-1. Elemental analysis structure (molecular formula C 34 H 26 BNO2): theoretical value: C, 83.10; H, 5.33; N, 2.85; test value: C, 83.15; H, 5.34; N, 2.81. LC-MS: measured value: 492.17 ([M+H] + ); exact mass: 491.21.

[0133] Under a nitrogen atmosphere, 0.06 mol of intermediate M-1 was added to a 500 ml three-necked flask, and it was dissolved by adding a mixed solvent (300 ml of toluene, 90 ml of H2O). Nitrogen was passed through and stirred for 1 hour, then 0.05 mol of intermediate P-1, 0.1 mol of K2CO3, and 0.005 mol of Pd(PPh3)4 were slowly added. It was heated to 90 °C and reacted for 8 hours. The reaction was observed by thin-layer chromatography (TLC) until the reaction was complete. After naturally cooling to room temperature, water was added to the reaction system for extraction, and liquid separation was carried out. The organic phase was rotary evaporated under reduced pressure until no distillate was obtained. The obtained substance was purified by a silica gel column to obtain the target compound. Elemental analysis structure (molecular formula C 58 H 38 N2O): Theoretical values: C, 89.43; H, 4.92; N, 3.60; Test values: C, 89.39; H, 4.90; N, 3.67. LC-MS: Measured value: 779.18 ([M+H] + ); Exact mass: 778.30.

[0134] The following compounds were prepared in the same manner as in Example 1, and the synthesis raw materials are shown in Table 1 below;

[0135] Table 1

[0136]

[0137]

[0138]

[0139] Detection method

[0140] Glass transition temperature Tg: Measured by differential scanning calorimetry (DSC, DSC204F1 differential scanning calorimeter from Netzsch, Germany), heating rate 10 °C / min.

[0141] HOMO energy level: Tested by an ionization energy test system (IPS3), and the test was in a vacuum environment.

[0142] 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, a tangent was made, and the value at the intersection of the tangent and the baseline was calculated.

[0143] Hole mobility: The material was made into a single-charge device and measured by the space-charge (induced) limited current method (SCLC).

[0144] Triplet energy level T1: Tested by a Fluorolog-3 series fluorescence spectrometer from Horiba. The test conditions for the material were 2×10-5 Toluene solution with a concentration of

[0145] For specific physical property test results, see Table 2.

[0146] Table 2

[0147]

[0148] As can be seen from the data in Table 2 above, the compounds of the present invention have suitable HOMO energy levels, high hole mobilities, and wide bandgaps (Eg), enabling the realization of organic electroluminescent devices with high efficiency and long lifetimes.

[0149] Preparation of organic electroluminescent devices

[0150] The molecular structural formulas of the materials involved in the following preparation process are shown as follows:

[0151]

[0152]

[0153] Device Comparative Example 1

[0154] Prepare an organic electroluminescent device according to the following steps:

[0155] As Figure 1As shown, for the substrate layer 1, the anode layer 2 (Ag (100 nm)) is washed, that is, alkali washing, pure water washing, and drying are carried out in sequence, and then ultraviolet-ozone washing is carried out to remove the organic residues on the surface of the anode layer. On the anode layer 2 after the above washing, using a vacuum evaporation device, HT1 and P-1 with a film thickness of 10 nm are evaporated as the hole injection layer 3, and the mass ratio of HT1 and P-1 is 97:3. Then, HT1 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 for the OLED light-emitting layer 6. The doping ratio of the doping material is 3% by weight, and the film thickness of the light-emitting layer is 20 nm. After the above light-emitting layer 6, HB1 is continuously evaporated with a film thickness of 8 nm as the hole blocking layer 7. On the above hole blocking layer 7, ET-1 and Liq are continuously evaporated, and the mass ratio of ET-1 and Liq is 1:1. The vacuum evaporation film thickness of this material is 30 nm, and this layer is the electron transport layer 8. On the electron transport layer 8, a LiF layer with a film thickness of 1 nm is fabricated through a vacuum evaporation device, and this layer is the electron injection layer 9. On the electron injection layer 9, a Mg:Ag electrode layer with a film thickness of 16 nm is fabricated through a vacuum evaporation device, and the mass ratio of Mg and Ag is 1:9. This layer is used as the cathode layer 10. On the cathode layer 10, 70 nm of CP-1 is vacuum-evaporated as the cover layer 11.

[0156] Device Comparative Examples 2-6

[0157] 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 3.

[0158] Device Examples 1-31

[0159] It is carried out according to the method of Device Comparative Example 1, except that the organic materials in the light-emitting auxiliary layer or the electron transport layer are respectively replaced with the organic materials shown in Table 3.

[0160] Table 3

[0161]

[0162]

[0163] Taking the row of Example 1 in the above table as an example, "P-1:HT1 = 3:97 10nm" in the second column table means that the materials used for the hole injection layer are compound HT1 and p-type doping material P-1. 3:97 refers to the weight ratio of p-type doping material P-1 to compound HT1 being 3:97, and 10nm represents the thickness of this layer; "210nm" in the fourth column table means that the material used is compound 2 and the thickness of this layer is 10nm. And so on for the meanings in other tables.

[0164] After preparing the OLED light-emitting device as described above, connect the cathode and anode with a known driving circuit to measure various performances of the device.

[0165] The measured performance results of the devices of Examples 1-31 and Comparative Examples 1-6 are shown in Table 4.

[0166] Table 4

[0167]

[0168] Note: LT95 refers to the time when the device brightness decays to 95% of the original brightness at a brightness of 50 mA / cm 2 ;

[0169] Voltage, current efficiency and color coordinates were measured using an IVL (current-voltage-brightness) test system (Suzhou Fosida Scientific Instruments Co., Ltd.); the current density was 10 mA / cm 2 ;

[0170] The life test system was the EAS-62C type OLED life test system of System Science Co., Ltd. of Japan.

[0171] From the results of Comparative Examples 1-6 and Examples 1-23 of the devices in Table 4, it can be seen that by using the aromatic amine compound of the present invention as the light-emitting auxiliary layer material, due to its high carrier transport rate and exciton blocking ability, the device efficiency and life are effectively improved. In particular, the efficiency of the device has been significantly improved unexpectedly (on the premise of maintaining a certain life advantage). By adjusting the ET layer material, the compound of the present invention application can further improve the device efficiency, as can be seen from the data of Examples 24-31.

Claims

1. An aromatic amine compound, characterized in that, The structure of the said compound is shown in general formula (1): In general formula (1), Ar1 and Ar2 each independently represent one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted furyl 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 benzofuranyl group, a substituted or unsubstituted spirofluorene group, a substituted or unsubstituted diphenylfluorene group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted benzo[a]phenanthryl group; R1 represents a structure shown in general formula (2), and general formula (2) is fused to general formula (1) at site a and b, site b and c, or site c and d through the * site; L, L1, L2, and L3 each independently represent a single bond, a phenylene group, a naphthylene group, or a biphenylene group; In general formula (2), X represents an oxygen atom, a sulfur atom, or N(R); R represents a phenyl group, a naphthyl group, or a biphenyl 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 benzofuranyl group, a furyl group, a thienyl group, a benzothienyl group, a dibenzothienyl group, a dibenzofuranyl group; 2. The aromatic amine compound according to claim 1, characterized in that, The structure of the said compound is shown in any one of general formulas (1-1) to (1-6): In general formulas (1-1) to (1-6), the definitions of Ar1, Ar2, L, L1, L2, L3, and X are the same as those defined in claim 1; 3. The aromatic amine compound according to claim 1, characterized in that, X represents an oxygen atom; L represents a single bond; L1 represents a phenylene group; 4. The aromatic amine compound according to claim 1, wherein X represents an oxygen atom; L represents a phenylene group; L1 represents a single bond; 5. The aromatic amine compound according to claim 1, wherein X represents an oxygen atom, and general formula (2) is fused to general formula (1) at site b and c or site c and d through the * site; 6. The aromatic amine compound according to claim 1, wherein Ar1 and Ar2 each independently represent one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted furyl 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 benzofuranyl group, a substituted or unsubstituted spirofluorene group, a substituted or unsubstituted diphenylfluorene group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted benzo[a]phenanthryl group; The substituent of the "substituted or unsubstituted" group is selected from one or more of a deuterium atom, a phenyl group, a naphthyl group, a biphenyl group, a benzofuranyl group, a furyl group, a dibenzofuranyl group, a thienyl group, a benzothienyl group, a dibenzothienyl group; 7. The aromatic amine compound according to claim 1, characterized in that, The specific structure of the said compound is any one of the following structures:

8. An organic electroluminescent device, which sequentially includes an anode, a hole transport region, a light-emitting region, an electron transport region, and a cathode, characterized in that, The hole transport region contains the aromatic amine compound according to any one of claims 1-7; 9. The organic electroluminescent device according to claim 8, wherein 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 according to any one of claims 1-7.

10. The organic electroluminescent device according to claim 8, characterized in that, The electron transport region contains an azacycle compound represented by the general formula (3): Among them, Ar5, Ar6, and Ar7 are each independently selected from substituted or unsubstituted C 6-30 aryl, substituted or unsubstituted C containing one or more heteroatoms 5-30 heteroaryl; L3 represents a single bond, a substituted or unsubstituted C 6-30 arylene, a substituted or unsubstituted C containing one or more heteroatoms 5-30 heteroarylene; one of them X1, X2, and X3 each independently represent N or CH, and at least one of X1, X2, and X3 represents N; The heteroatom is selected from N, O, or S; The substituents for substituting the "substituted or unsubstituted" group are one or more of a deuterium atom, a phenyl group, a naphthyl group, a biphenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a pyridyl group, or a pyrimidinyl group.

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