Compound, hole transport material, organic electroluminescent device and display device

Abstract

The invention relates to the technical field of organic light-emitting display, in particular to a compound, a hole transport material, an organic light-emitting device and a display device. The invention provides a compound as shown in a general formula (I), which can be used for hole transport materials. The compound has a parent structure of substituted carbazole compound substituted arylamine, is high in bond energy between atoms, has good thermal stability, is beneficial to solid-state accumulation between molecules, is high in hole transition capability, and can effectively reduce the voltage of a device and prolong the service life of the material when being used as a hole transport material. The invention also provides an organic electroluminescent device and a display device containing the compound shown in the general formula (I).

Description

Technical Field

[0001] This invention relates to the field of organic light-emitting display technology, and particularly to a compound, a hole transport material, an organic electroluminescent device, and a display apparatus. Background Technology

[0002] Electroluminescence (EL) refers to the phenomenon where luminescent materials emit light when excited by an electric field and current. It is a process that directly converts electrical energy into light energy. Organic electroluminescent displays (OLEDs) possess a series of advantages, including self-illumination, low-voltage DC drive, all-solid-state operation, wide viewing angle, light weight, and simple composition and manufacturing process. Compared to liquid crystal displays (LCDs), OLEDs do not require a backlight, have a wider viewing angle, lower power consumption, and a response speed up to 1000 times faster than LCDs, while their manufacturing cost is lower than that of LCDs with equivalent resolution. Therefore, organic electroluminescent devices have a very broad application prospect.

[0003] With the continuous advancement of OLED technology in the fields of lighting and display, people are paying more attention to the research on high-efficiency organic materials that affect the performance of OLED devices. An efficient and long-life organic electroluminescent device is usually the result of the optimized combination of device structure and various organic materials, which provides chemists with great opportunities and challenges to design and develop functional materials with various structures.

[0004] Compared to inorganic light-emitting materials, organic electroluminescent materials have many advantages, such as: good processing performance, allowing for film deposition on any substrate via evaporation or spin coating, enabling flexible and large-area displays; and the ability to adjust the optical, electrical, and stability properties of the material by altering its molecular structure, providing a wide range of material choices. The most common OLED device structures typically include the following types of organic materials: hole injection materials, hole transport materials, electron transport materials, and various colored luminescent materials (dyes or doped guest materials) and corresponding host materials. Hole transport materials further include auxiliary luminescent materials. Among these, hole transport materials, as an important functional material, directly affect hole mobility and ultimately the luminous efficiency of OLEDs. However, currently used hole transport materials in OLEDs achieve relatively low hole mobility, poor energy level matching with adjacent layers, and cannot simultaneously achieve both efficiency and lifetime, severely restricting the display functionality and development of OLED display devices. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems in the prior art, the present invention provides a compound, a hole transport material, an organic electroluminescent device and a display device, which can improve the working efficiency and extend the service life of the organic electroluminescent device.

[0006] A first aspect of the present invention is to provide a compound having the general formula shown in formula (I):

[0007]

[0008] The substituents R1-R8 are independently selected from hydrogen, deuterium, oxygen, sulfur, nitrogen, C1-C4 alkyl, C3-C6 cycloalkanes, substituted or unsubstituted C6-C30 aromatic groups, and adjacent substituents can be linked to form a ring.

[0009] Substituent R9-R 12 Each of the substituents is independently selected from hydrogen, C1-C4 alkyl, substituted or unsubstituted C6-C30 aromatic groups, and adjacent substituents can be linked to form a ring;

[0010] Substituents R and R' are selected from hydrogen, substituted or unsubstituted C6-C30 aryl groups, substituted or unsubstituted C5-C30 heteroaryl groups, and at least one is not hydrogen;

[0011] m is selected from 0, 1, 2;

[0012] M has the structure shown in equation (II):

[0013]

[0014] The heteroatoms on the heteroaryl group are each independently selected from oxygen, sulfur, or nitrogen;

[0015] The hydrogen atoms on the aromatic group and the heteroaryl group can each be independently replaced by Ra, which is independently selected from deuterium, halogen, nitro, cyano, C1-C4 alkyl, C5-C20 cycloalkyl, phenyl, biphenyl, terphenyl or naphthyl.

[0016] A second aspect of the present invention is to provide a hole transport material comprising at least one of the compounds provided in the first aspect of the present invention.

[0017] A third aspect of the present invention provides an organic electroluminescent device comprising at least one of the hole transport materials provided in the second aspect of the present invention.

[0018] A fourth aspect of the present invention provides a display device comprising the organic electroluminescent device of the third aspect of the present invention.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] The compound disclosed in this invention has a parent structure of substituted carbazole, high interatomic bond energy, good thermal stability, and is conducive to solid-state stacking between molecules. It also has strong hole transition capability. When used as an auxiliary light-emitting layer material, it can effectively reduce device voltage and improve material lifespan.

[0021] The compound described in this invention, when used in the auxiliary light-emitting layer, has a suitable energy level with adjacent layers, which is beneficial for hole injection and migration, effectively reducing the driving voltage. At the same time, the high hole migration rate enables good luminous efficiency in the device.

[0022] The compounds of this invention have a large conjugated plane, which is beneficial for molecular stacking, exhibits good thermodynamic stability, and demonstrates long lifetime in devices;

[0023] Meanwhile, the preparation process of the derivatives described in this invention is simple and easy to implement, the raw materials are readily available, and it is suitable for industrial production. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a typical organic electroluminescent device.

[0025] Figure label:

[0026] 1. Substrate; 2. Reflective anode electrode; 3. Hole injection layer; 4. Hole transport layer; 5. Light-emitting layer; 6. Electron transport layer; 7. Electron injection layer; 8. Cathode electrode. Detailed Implementation

[0027] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0028] A first aspect of the present invention provides a compound of general formula (I):

[0029]

[0030] The substituents R1-R8 are independently selected from hydrogen, deuterium, oxygen, sulfur, nitrogen, C1-C4 alkyl, C3-C6 cycloalkanes, substituted or unsubstituted C6-C30 aromatic groups, and adjacent substituents can be linked to form a ring.

[0031] Substituent R9-R 12 Each of the substituents is independently selected from hydrogen, C1-C4 alkyl, substituted or unsubstituted C6-C30 aromatic groups, and adjacent substituents can be linked to form a ring;

[0032] Substituents R and R' are selected from hydrogen, substituted or unsubstituted C6-C30 aryl groups, substituted or unsubstituted C5-C30 heteroaryl groups, and at least one is not hydrogen;

[0033] m is selected from 0, 1, 2;

[0034] M has the structure shown in equation (II):

[0035]

[0036] The heteroatoms on the heteroaryl group are each independently selected from oxygen, sulfur, or nitrogen;

[0037] The hydrogen atoms on the aromatic group and the heteroaryl group can each be independently replaced by Ra, which is independently selected from deuterium, halogen, nitro, cyano, C1-C4 alkyl, C5-C20 cycloalkyl, phenyl, biphenyl, terphenyl or naphthyl.

[0038] Preferably, the substituents R1-R8 are independently selected from hydrogen, deuterium, hydroxyl, mercapto, methyl, ethyl, isopropyl, tert-butyl, cyclopentyl, cyclohexyl, unsubstituted or Ra-substituted groups of the following: phenyl, biphenyl, naphthyl, phenanthrene, fluorenyl, dibenzofuranyl, dibenzothiopheneyl, carbazoleyl, aniline.

[0039] Preferably, the substituent R9-R 12 The following groups are selected independently from hydrogen, methyl, ethyl, isopropyl, tert-butyl, unsubstituted or substituted by Ra: phenyl, biphenyl, terphenyl, naphthyl, phenanthrene, triphenylene, fluorenyl, dibenzofuranyl, dibenzothiophene, 9,9-dimethylfluorenyl, spirofluorenyl.

[0040] Preferably, the substituents R and R' are selected from hydrogen, unsubstituted or substituted by Ra, and the following groups: phenyl, biphenyl, terphenyl, naphthyl, phenanthrene, triphenylene, fluorenyl, benzofuranyl, dibenzofuranyl, benzothiophene, dibenzothiophene, 9,9-dimethylfluorenyl, spirofluorenyl, aromatic amino, and carbazole.

[0041] Preferably, the compound has the structural formulas shown in A1-A25:

[0042]

[0043]

[0044] A second aspect of the present invention provides a hole transport material comprising at least one of the compounds provided in the first aspect of the present invention.

[0045] A third aspect of the present invention provides an organic electroluminescent device comprising at least one of the hole transport materials provided in the second aspect of the present invention.

[0046] In this invention, there are no particular restrictions on the type and structure of organic electroluminescent devices, as long as the hole transport material provided by this invention can be used.

[0047] The organic electroluminescent device of the present invention can be a top-emitting device, for example, comprising an anode, a hole injection layer, a hole transport layer, an emitting layer, an electron transport layer, an electron injection layer, and a transparent or semi-transparent cathode in sequence on a substrate.

[0048] The organic electroluminescent device of the present invention can also be a bottom-emitting device, for example, comprising a transparent or semi-transparent anode, a hole injection layer, a hole transport layer, an emitting layer, an electron transport layer, an electron injection layer and a cathode structure in sequence on a substrate.

[0049] The organic electroluminescent device of the present invention can also be a light-emitting device with a dual-sided light-emitting structure, for example, comprising a transparent or semi-transparent anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer and a transparent or semi-transparent cathode structure in sequence on a substrate.

[0050] In the organic electroluminescent device of the present invention, except for the hole transport layer which contains the hole transport material provided by the present invention, other layers may use any material used for the layers in the prior art.

[0051] Figure 1 A schematic diagram of a typical organic electroluminescent device is shown, in which, from bottom to top, a substrate 1, a reflective anode electrode 2, a hole injection layer 3, a hole transport layer 4, a light-emitting layer 5, an electron transport layer 6, an electron injection layer 7, and a cathode electrode 8 are arranged sequentially.

[0052] Understandable. Figure 1 The diagram only schematically illustrates the structure of a typical organic electroluminescent device. This invention is not limited to this structure, and the hole transport material of this invention can be used in any type of organic electroluminescent device. For example, organic electroluminescent devices may also include an electron blocking layer, a hole blocking layer, a light extraction layer, etc. In practical applications, these layers can be added or omitted depending on the specific circumstances.

[0053] For convenience, the following references Figure 1 The organic electroluminescent device of the present invention will be described, but this does not imply any limitation on the scope of protection of the present invention. It is understood that all organic electroluminescent devices capable of using the hole transport material of the present invention are within the scope of protection of the present invention.

[0054] In this invention, the substrate 1 is not particularly limited and can be a conventional substrate used in organic electroluminescent devices in the prior art, such as glass, polymer materials, and glass and polymer materials with TFT (thin-film field-effect transistor) components.

[0055] In this invention, the material of the reflective anode electrode 2 is not particularly limited. It can be selected from transparent conductive materials known in the prior art such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), and low-temperature polycrystalline silicon (LTPS). It can also be metallic materials such as silver and its alloys, aluminum and its alloys, organic conductive materials such as PEDOT (poly(3,4-ethylenedioxythiophene)), or multilayer structures of the above materials.

[0056] In this invention, the material of the hole injection layer 3 is not particularly limited, and hole injection materials known in the art or hole transport materials provided by this invention can be selected as hole injection materials.

[0057] For example, the material of the hole injection layer 3 may be selected from at least one of the following HT-1 to HT-31 compounds:

[0058]

[0059]

[0060] In this invention, the hole injection layer 3 may further include a p-type dopant. The type of p-type dopant is not particularly limited, and various p-type dopants known in the art can be used. For example, the p-type dopant may be selected from at least one of the following compounds:

[0061]

[0062] In this invention, the amount of p-type dopant used is not particularly limited and can be any amount known to those skilled in the art.

[0063] In this invention, the hole transport layer 4 comprises at least one of the hole transport materials of this invention. The hole transport layer 4 may also comprise any combination of at least one of the hole transport materials of this invention and known hole transport materials. Currently known hole transport materials may be selected from at least one of the compounds HT-1 to HT-31 described above, but are not limited to the compounds listed above.

[0064] In this invention, the luminescent material of the luminescent layer 5 is not particularly limited, and any luminescent material known to those skilled in the art can be used. For example, the luminescent material may comprise a host material and a guest material. For instance, the known host material of the luminescent layer 5 may be selected from at least one of the following compounds: BH-1 to BH-10.

[0065]

[0066] In this application, there are no particular limitations on the guest material of the luminescent layer 5, and at least one of the guest materials of the luminescent layer 5 known in the art can be used. For example, the guest material of the luminescent layer 5 can be selected from, but is not limited to, at least one of the following BD-1 to BD-9 compounds:

[0067]

[0068]

[0069] In this invention, the material of the electron transport layer 6 is not particularly limited and can be made of electron transport materials known in the art. For example, the material of the electron transport layer 6 can be selected from at least one of the following ET-1 to ET-57 compounds:

[0070]

[0071]

[0072]

[0073] In this invention, the electron transport layer 6 may further include an n-type dopant. The type of n-type dopant is not particularly limited, and various n-type dopants known in the art can be used. For example, the n-type dopant may be a compound represented by the following formula:

[0074]

[0075] In this invention, the amount of the n-type dopant is not particularly limited and can be any amount known to those skilled in the art.

[0076] In this invention, the material of the electron injection layer 7 is not particularly limited, and electron injection materials known in the art can be used. For example, it can include, but is not limited to, at least one of the following materials in the prior art: LiQ (lithium 8-hydroxyquinoline), LiF (lithium fluoride), NaCl, CsF (cesium fluoride), Li2O (lithium oxide), Cs2CO3 (cesium carbonate), BaO, Na, Li, Ca, etc.

[0077] In this invention, the material of the cathode electrode 8 is not particularly limited. For example, it can be selected from, but is not limited to, magnesium-silver mixtures, LiF / Al, ITO, Al and other metals, metal mixtures, oxides and the like.

[0078] A fourth aspect of the present invention provides a display device comprising the organic electroluminescent device provided by the present invention. The display device includes, but is not limited to, a monitor, a television, a tablet computer, a mobile communication terminal, etc.

[0079] There are no particular limitations on the method for preparing the organic electroluminescent device of the present invention, and any method known in the art can be used. For example, the present invention can be prepared by the following method:

[0080] (1) Clean the reflective anode electrode 2 on the substrate 1 of the top-emitting OLED device. In the cleaning machine, the electrode is cleaned by chemical washing, water washing, brushing, high-pressure water washing, air knife and other steps, and then heated.

[0081] (2) Hole injection material is vacuum-deposited on the reflective anode electrode 2 as a hole injection layer 3;

[0082] (3) Hole transport material is vacuum-deposited on hole injection layer 3 as hole transport layer 4;

[0083] (4) A light-emitting layer 5 is vacuum-deposited on the hole transport layer 4, the light-emitting layer 5 containing a host material and a guest material;

[0084] (5) Electron transport material is vacuum-deposited on the light-emitting layer 5 as electron transport layer 6;

[0085] (6) Vacuum evaporation of electron injection material on electron transport layer 6 to form electron injection layer 7. The electron injection material is selected from one or a combination of several materials such as LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, and Ca.

[0086] (7) Vacuum evaporation of cathode material on electron injection layer 7 as cathode electrode 8.

[0087] The above description only illustrates the structure and fabrication method of a typical organic electroluminescent device. It should be understood that the present invention is not limited to this structure. The hole transport material of the present invention can be used in organic electroluminescent devices of any structure, and the organic electroluminescent device can be fabricated using any fabrication method known in the art.

[0088] The synthesis method of the compounds of the present invention is not particularly limited, and any method known to those skilled in the art can be used for synthesis. The following examples illustrate the synthesis process of the compounds of the present invention.

[0089] Synthesis Example 1: Synthesis of Compound A1

[0090]

[0091] 100 mmol of carbazole, 100 mmol of 3-fluoronitrobenzene, 41.4 g of potassium carbonate (300 mmol), and 800 ml of DMF (N,N-dimethylformamide) were added to a reaction flask, and the mixture was reacted at 120 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder M1.

[0092] 100 mmol of M1, 200 mmol of stannous chloride, and 800 ml of ethanol were added to a reaction flask, and the mixture was reacted at 70 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, separated, washed with water, and concentrated. The resulting solid was purified by recrystallization from toluene to obtain a white powder, M2.

[0093] 100 mmol of 1,4-dibromonaphthalene, 100 mmol of phenylboronic acid, 41.4 g of potassium carbonate (300 mmol), 800 mL of tetrahydrofuran (THF), and 200 mL of water were added to a reaction flask, along with 1 mmol of tetra(triphenylphosphine)palladium (Pd(PPh3)4). The reaction was carried out at 60 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M3.

[0094] 100 mmol of M2, 200 mmol of M3, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 2 mol% of palladium dibenzylacetone (Pd(dba)2). The reaction was carried out at 120 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder, Al.

[0095] 1H NMR (400MHz, Chloroform) δ8.93(d,J=8.0Hz,2H),8.54(d,J=7.2Hz,1H),8.26(d,J=8.0Hz,2H),8.18(d,J=7.2H z,1H),7.85-7.72(m,5H),7.56(d,J=10.0Hz,3H),7.48-7.31(m,13H),7.20–7.12(m,5H),7.03(d,J=7.2Hz,1H).

[0096] Synthesis Example 2: Synthesis of Compound A5

[0097]

[0098] 100 mmol of carbazole, 100 mmol of 3-fluorobromobenzene, 41.4 g of potassium carbonate (300 mmol), and 800 ml of DMF (N,N-dimethylformamide) were added to a reaction flask, and the mixture was reacted at 120 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder M1.

[0099] 100 mmol of M1, 100 mmol of 3-chlorophenylboronic acid, 41.4 g of potassium carbonate (300 mmol), 800 mL of tetrahydrofuran (THF), and 200 mL of water were added to a reaction flask, along with 1 mmol of tetra(triphenylphosphine)palladium (Pd(PPh3)4). The reaction was carried out at 60 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder, M2.

[0100] 100 mmol of 2,6-dibromonaphthalene, 100 mmol of phenylboronic acid, 41.4 g of potassium carbonate (300 mmol), 800 mL of tetrahydrofuran (THF), and 200 mL of water were added to a reaction flask, along with 1 mmol of tetra(triphenylphosphine)palladium (Pd(PPh3)4). The reaction was carried out at 60 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M3.

[0101] 100 mmol of 1-naphthylamine, 100 mmol of M3, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% of bis(dba)2-dibenzylacetone palladium (Pd(dba)2). The reaction was carried out at 120 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder, M4.

[0102] 100 mmol of M2, 100 mmol of M4, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% of palladium dibenzylacetone (Pd(dba)2). The reaction was carried out at 120 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder A5.

[0103] 1H NMR(400MHz,Chloroform)δ8.55(d,J=7.2Hz,1H),8.26-8.10(m,3H),7.84(d,J=7.6Hz,2H) ,7.75(d,J=7.6Hz,2H),7.65-7.36(m,16H),7.32(s,1H),7.25(s,1H),7.21-7.08(m,8H)).

[0104] Synthesis Example 3: Synthesis of Compound A8

[0105]

[0106] 100 mmol of carbazole, 100 mmol of 2-bromo-5-chlorofluorobenzene, 41.4 g of potassium carbonate (300 mmol), and 800 ml of DMF (N,N-dimethylformamide) were added to a reaction flask, and the mixture was reacted at 120 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder M1.

[0107] 100 mmol of M1, 100 mmol of phenylboronic acid, 41.4 g of potassium carbonate (300 mmol), 800 mL of tetrahydrofuran (THF), and 200 mL of water were added to a reaction flask, along with 1 mmol of tetra(triphenylphosphine)palladium (Pd(PPh3)4). The reaction was carried out at 60 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder, M2.

[0108] 100 mmol of 1-bromo-4-naphthylamine, 100 mmol of phenylboronic acid, 41.4 g of potassium carbonate (300 mmol), 800 mL of tetrahydrofuran (THF), and 200 mL of water were added to a reaction flask, along with 1 mmol of tetra(triphenylphosphine)palladium (Pd(PPh3)4). The reaction was carried out at 60 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M3.

[0109] 100 mmol of 2,6-dibromonaphthalene, 100 mmol of phenylboronic acid, 41.4 g of potassium carbonate (300 mmol), 800 mL of tetrahydrofuran (THF), and 200 mL of water were added to a reaction flask, along with 1 mmol of tetra(triphenylphosphine)palladium (Pd(PPh3)4). The reaction was carried out at 60 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M4.

[0110] 100 mmol of M3, 100 mmol of M4, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% of palladium dibenzylacetone (Pd(dba)2). The reaction was carried out at 120 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder, M5.

[0111] 100 mmol of M2, 100 mmol of M5, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% of palladium dibenzylacetone (Pd(dba)2). The reaction was carried out at 120 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder, A8.

[0112] 1H NMR (400MHz, Chloroform) δ8.92(d,J=7.2Hz,1H),8.52(d,J=7.2Hz,1H),8.27(d,J=7.2Hz,1H),8.12(d,J=7.2Hz,1H),7. 90(d,J=7.6Hz,2H),7.85(s,1H),7.82(d,J=7.2Hz,1H),7.75(d,J=7.6Hz,3H),7.58–7.32(m,17H),7.518–7.05(m,10H).

[0113] Synthesis Example 4: Synthesis of Compound A12

[0114]

[0115] 100 mmol of 4-dibenzofuranboronic acid, 100 mmol of 2-bromonitrobenzene, 41.4 g of potassium carbonate (300 mmol), 800 mL of tetrahydrofuran (THF), and 200 mL of water were added to a reaction flask, along with 1 mmol of tetra(triphenylphosphine)palladium (Pd(PPh3)4). The reaction was carried out at 60 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M1.

[0116] 100 mmol of M1, 300 mmol of triphenylphosphine, and 800 mL of o-dichlorobenzene were added to a reaction flask, and the mixture was reacted at 120 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature, concentrated, and separated by column chromatography. The obtained solid was purified by recrystallization from toluene to obtain a white powder M2.

[0117] 100 mmol of M2, 100 mmol of 3-bromofluorobenzene, 41.4 g of potassium carbonate (300 mmol), and 800 ml of DMF (N,N-dimethylformamide) were added to a reaction flask, and the mixture was reacted at 120 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder, M3.

[0118] 100 mmol of 1-bromo-4-naphthylamine, 100 mmol of phenylboronic acid, 41.4 g of potassium carbonate (300 mmol), 800 mL of tetrahydrofuran (THF), and 200 mL of water were added to a reaction flask, along with 1 mmol of tetra(triphenylphosphine)palladium (Pd(PPh3)4). The reaction was carried out at 60 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M4.

[0119] 100 mmol of 2,6-dibromonaphthalene, 100 mmol of phenylboronic acid, 41.4 g of potassium carbonate (300 mmol), 800 mL of tetrahydrofuran (THF), and 200 mL of water were added to a reaction flask, along with 1 mmol of tetra(triphenylphosphine)palladium (Pd(PPh3)4). The reaction was carried out at 60 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M5.

[0120] Add 100 mmol of M4, 100 mmol of M5, 28.83 g of sodium tert-butoxide (300 mmol), 800 ml of xylene into a reaction flask, and add 1 mol% of bis(dibenzylideneacetone)palladium (Pd(dba)2). React at 120 °C for 12 h. After the reaction is completed, stop the reaction, cool the reactant to room temperature, add water, filter, wash with water, and recrystallize and purify the obtained solid with toluene to obtain white powder M6.

[0121] Add 100 mmol of M3, 100 mmol of M6, 28.83 g of sodium tert-butoxide (300 mmol), 800 ml of xylene into a reaction flask, and add 1 mol% of bis(dibenzylideneacetone)palladium (Pd(dba)2). React at 120 °C for 12 h. After the reaction is completed, stop the reaction, cool the reactant to room temperature, add water, filter, wash with water, and recrystallize and purify the obtained solid with toluene to obtain white powder A12.

[0122] 1H NMR (400 MHz, Chloroform) δ 8.95 (d, J = 7.6 Hz, 1H), 8.56 (d, J = 7.2 Hz, 1H), 8.27 (d, J = 7.6 Hz, 1H), 7.98 (d, J = 8.0 Hz, 2H), 7.84 (d, J = 7.6 Hz, 1H), 7.80 (t, J = 7.6 Hz, 4H), 7.75 (s, 1H), 7.60 - 7.32 (m, 19H), 7.20 - 7.08 (m, 5H), 7.05 (d, J = 7.2 Hz, 1H).

[0123] Other compounds of the present invention can be synthesized by selecting appropriate raw materials according to the ideas of the above Synthesis Examples 1-4, or any other suitable methods and raw materials can be selected for synthesis.

[0124] Example 1

[0125] Ultrasonically treat the glass plate coated with the ITO transparent conductive layer in a commercial cleaning agent, rinse it in deionized water, ultrasonically degrease it in an acetone-ethanol mixed solvent, bake it in a clean environment until all moisture is removed, clean it with ultraviolet light and ozone, and bombard the surface with a low-energy cation beam;

[0126] Place the above-mentioned glass substrate with the anode in a vacuum chamber, evacuate to less than 10 -5 Torr, vacuum-evaporate HT-11 as the hole injection layer 3 on the above-mentioned anode layer film at a evaporation rate of 0.1 nm / s and an evaporation film thickness of 10 nm;

[0127] HT-11 material is vacuum-deposited on top of hole injection layer 3 as hole transport layer 4 and Al material is vacuum-deposited as auxiliary light-emitting layer (belonging to hole transport layer 4). The evaporation rate of HT-11 material is 0.1 nm / s and the evaporation film thickness is 80 nm. The evaporation rate of Al material is 0.1 nm / s and the evaporation film thickness is 10 nm.

[0128] A light-emitting layer 5 is vacuum-deposited on the auxiliary light-emitting layer. The light-emitting layer 5 includes a host material BH-1 and a guest material BD-1. The deposition is carried out using a multi-source co-evaporation method. The deposition rate of the host material BH-1 is adjusted to 0.1 nm / s, the deposition rate of the guest material BD-1 is 3% of the deposition rate of the host material, and the total deposition film thickness is 30 nm.

[0129] An electron transport layer 6 is vacuum-deposited on top of the light-emitting layer 5. ET-42 is selected as the electron transport material, with a deposition rate of 0.1 nm / s and a deposition film thickness of 30 nm.

[0130] A 0.5 nm thick LiF layer was vacuum-deposited on the electron transport layer 6 as the electron injection layer 7 at a deposition rate of 0.1 nm / s.

[0131] Finally, an aluminum layer with a thickness of 150 nm is deposited on the electron injection layer 7 as the cathode electrode 8 of the organic electroluminescent device, with a deposition rate of 0.1 nm / s.

[0132] Examples 2-4

[0133] Except for replacing A1 with A5, A8, and A12 respectively, the rest is the same as in Example 1. The test results are shown in Table 1.

[0134] Comparative Example 1

[0135] Except for replacing A1 with HT-28, the rest is the same as in Example 1. The test results are shown in Table 1.

[0136] Comparative Example 2

[0137] Except for replacing A1 with R1, the rest is the same as in Example 1. The test results are shown in Table 1.

[0138]

[0139] The organic electroluminescent devices prepared by the above process were subjected to the following performance measurements:

[0140] Under the same brightness, the driving voltage and current efficiency, as well as the lifetime of the organic electroluminescent devices prepared in the examples and comparative examples, were measured using a digital source meter and a luminance meter. Specifically, the voltage was increased at a rate of 0.1V per second, and the measurement was performed when the brightness of the organic electroluminescent device reached 1000 cd / m². 2The voltage at that time is the driving voltage, and the current density at that time is measured simultaneously; the ratio of brightness to current density is the current efficiency; the life test of LT95 is as follows: using a luminance meter at 1000 cd / m² 2 At a constant current, the brightness of the organic electroluminescent device decreased to 950 cd / m² under the specified brightness. 2 The time is in hours.

[0141] Table 1 Performance results of organic electroluminescent devices

[0142]

[0143] As can be seen from the data in the table above, the compound prepared by this invention can be used as an auxiliary light-emitting layer material for organic electroluminescent devices, which can effectively reduce the driving voltage, improve the current efficiency, and extend the device life. It is a high-performance auxiliary light-emitting layer material.

[0144] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A compound, characterized in that, It has the general formula shown in equation (I): The substituents R1-R8 are independently selected from hydrogen, deuterium, oxygen, sulfur, nitrogen, C1-C4 alkyl, C3-C6 cycloalkanes, substituted or unsubstituted C6-C30 aromatic groups, and adjacent substituents can be linked to form a ring. Substituent R9-R 12 Each of the substituents is independently selected from hydrogen, C1-C4 alkyl, substituted or unsubstituted C6-C30 aromatic groups, and adjacent substituents can be linked to form a ring; Substituents R and R' are selected from hydrogen, substituted or unsubstituted C6-C30 aryl groups, substituted or unsubstituted C5-C30 heteroaryl groups, and at least one is not hydrogen; m is selected from 0, 1, 2; M has the structure shown in equation (II): The heteroatoms on the heteroaryl group are each independently selected from oxygen, sulfur, or nitrogen; The hydrogen atoms on the aromatic group and the heteroaryl group can each be independently replaced by Ra, which is independently selected from deuterium, halogen, nitro, cyano, C1-C4 alkyl, C5-C20 cycloalkyl, phenyl, biphenyl, terphenyl or naphthyl.

2. The compound according to claim 1, characterized in that, The substituents R1-R8 are independently selected from hydrogen, deuterium, hydroxyl, mercapto, methyl, ethyl, isopropyl, tert-butyl, cyclopentyl, cyclohexyl, and the following groups that are unsubstituted or substituted by Ra: phenyl, biphenyl, naphthyl, phenanthrene, fluorenyl, dibenzofuranyl, dibenzothiopheneyl, carbazoyl, and aniline.

3. The compound according to claim 1, characterized in that, Substituent R9-R 12 The following groups are selected independently from hydrogen, methyl, ethyl, isopropyl, tert-butyl, unsubstituted or substituted by Ra: phenyl, biphenyl, terphenyl, naphthyl, phenanthrene, triphenylene, fluorenyl, dibenzofuranyl, dibenzothiophene, 9,9-dimethylfluorenyl, spirofluorenyl.

4. The compound according to claim 1, characterized in that, Substituents R and R' are selected from hydrogen, unsubstituted or substituted by Ra, and the following groups: phenyl, biphenyl, terphenyl, naphthyl, phenanthrene, triphenylene, fluorenyl, benzofuranyl, dibenzofuranyl, benzothiophene, dibenzothiophene, 9,9-dimethylfluorenyl, spirofluorenyl, aromatic amino, carbazole.

5. The compound according to claim 1, characterized in that, The compound has the structural formulas shown in A1-A25:

6. A hole transport material, characterized in that it comprises at least one of the compounds according to any one of claims 1-5.

7. An organic electroluminescent device, characterized in that, It includes at least one of the hole transport materials described in claim 6.

8. A display device, characterized in that, It includes the organic electroluminescent device as described in claim 7.

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