Luminescence auxiliary material, preparation method thereof and application thereof

Abstract

The present invention provides a luminescence auxiliary material, a preparation method thereof, and an application thereof. The amine unit of the luminescence auxiliary material provided by the present application has a low ionization potential, good electron-donating property, and high hole mobility. At the same time, the symmetry of the molecule is reduced, the conformational isomers of the molecule are increased, and the compound has a rigid planar structure. At the same time, the molecular weight is increased, so that the molecules are not easy to crystallize or aggregate, and the material has high photothermal stability. Therefore, after the luminescence auxiliary material of the present application is used in an organic electroluminescent device, the luminescence efficiency of the device is improved, the life is delayed, and the driving voltage is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent materials, and in particular to a luminescent auxiliary material, a preparation method thereof and applications thereof. Background Art

[0002] Organic electroluminescence (OLED) has been the most researched display technology in the past 20 years and is widely recognized by the industry as one of the most promising future flat-panel display technologies, potentially replacing liquid crystals. Compared to LCDs, OLEDs offer advantages such as ultra-thinness, self-luminescence, wide viewing angles, fast response times, high luminous efficiency, excellent temperature adaptability, simple production processes, low drive voltages, low energy consumption, and low cost. Their light-emitting layer consists of a thin film of organic molecules tens of nanometers thick, and the display device is only a few millimeters thick.

[0003] An organic electroluminescent element is a self-luminous element that utilizes the following principle: by applying an electric field, the phosphorescent material emits light by utilizing the recombination energy of holes injected from the anode and electrons injected from the cathode. It has the following structure: an anode, a cathode, and an organic material layer between the two. In order to improve the efficiency and stability of the organic electroluminescent element, the organic material layer generally includes multiple layers with different materials, such as a hole injection layer (HIL), a hole transport layer (HTL), a light-emitting layer, an electron transport layer (ETL), and an electron injection layer (EIL). In such an organic light-emitting element, when a voltage is applied between the anode and the cathode, holes from the anode and electrons from the cathode are injected into the organic material layer, and the generated excitons generate light with a specific wavelength when they migrate to the ground state. The hole transport layer can change the hole transfer efficiency, luminous efficiency, lifespan, etc. of holes to the light-emitting layer. Therefore, copper phthalocyanine (CuPc), 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB), N,N′-diphenyl-N,N′-bis(3-methylphenyl)-(1,1′-biphenyl)-4,4′-diamine (TPD), etc. are currently used as hole transport materials.

[0004] Currently, research on organic electroluminescent materials has been extensively conducted in academia and industry, and a large number of high-performance organic electroluminescent materials have been developed. Overall, the future direction of organic electroluminescent devices is to develop high-efficiency, long-life, and low-cost white light devices and full-color display devices. However, the industrialization of this technology still faces many key challenges. Therefore, the design and search for stable and efficient compounds as new materials for organic electroluminescent devices to overcome the shortcomings encountered in practical applications is a key focus and future research trend in organic electroluminescent device materials research. Summary of the Invention

[0005] The technical problem solved by the present invention is to provide a luminescence auxiliary material, and the device prepared by the material has excellent thermal stability, good luminescence efficiency and long service life.

[0006] In view of this, the present application provides a luminescent auxiliary material as shown in formula (I),

[0007]

[0008] Wherein, m and n are each independently selected from 0 or 1, and cannot be 0 or 1 at the same time;

[0009] X is independently selected from -O-, -S-, -SO2-, -C(R5R6)-, -N(R7)-, -Si(R8R9)-, -Sn(R 10 R 11 )-or-Ge(R 12 R 13 )-;

[0010] L1 and L2 are each independently selected from a linking bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group;

[0011] R1-R4 are each independently selected from hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, amino, silyl, borane, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted 3-30-membered heterocycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted 3-20-membered heteroaryl, substituted or unsubstituted 3-25-membered heteroarylamine, substituted or unsubstituted C6-C60 arylamine, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C6-C60 aryloxy;

[0012] R5~R 13 each independently selected from a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted 3-20-membered heterocycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted 3-30-membered heteroaryl group, a substituted or unsubstituted 3-30-membered heteroarylamino group, and a substituted or unsubstituted (C6-C60)arylamino group;

[0013] Ar1 to Ar4 are each independently selected from a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted 3-20-membered heterocycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted 3-30-membered heteroaryl group, a substituted or unsubstituted 3-15-membered heteroarylamine group, and a substituted or unsubstituted C6-C60 arylamine group.

[0014] Preferably, L1 and L2 are each independently selected from a linking bond, a substituted or unsubstituted C6-C18 arylene group, and a substituted or unsubstituted 3- to 18-membered heteroarylene group.

[0015] Preferably, R1 to R4 are each independently selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted 3- to 15-membered heteroaryl, wherein the heteroatom in the heteroaryl is selected from O, N or S; R5 to R 13 Each is independently selected from a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C20 aryl group, and a substituted or unsubstituted 3-20-membered heteroaryl group, wherein the heteroatom in the heteroaryl group is selected from O, N or S.

[0016] Preferably, Ar1 to Ar4 are each independently selected from a substituted or unsubstituted C6 to C25 aryl group, a substituted or unsubstituted 3- to 20-membered heteroaryl group, a substituted or unsubstituted 3- to 10-membered heteroarylamine group, or a substituted or unsubstituted C6 to C30 arylamine group.

[0017] Preferably, the structural formula of the luminescent material is specifically as shown in formula (I-1) or formula (I-2);

[0018]

[0019] Preferably, Ar1 to Ar6 are independently selected from the following structures:

[0020]

[0021]

[0022] Preferably, R5 to R7 are each independently selected from methyl, ethyl, phenyl or methylbenzene.

[0023] Preferably, the luminescence auxiliary material is specifically:

[0024]

[0025]

[0026]

[0027]

[0028]

[0029] The present application also provides a method for preparing the luminescence auxiliary material, comprising the following steps:

[0030] Under nitrogen protection, raw material A and raw material B are reacted in a palladium catalyst, a phosphine ligand and sodium tert-butoxide to obtain a first intermediate as shown in formula (II);

[0031] Reacting raw material C and raw material D in the presence of copper iodide and potassium sulfate to obtain a second intermediate as shown in formula (III);

[0032] The second intermediate, Pd(OAc), PCy3 and K2CO3 are reacted to obtain a third intermediate as shown in formula (IV);

[0033] Under nitrogen protection, the third intermediate and the first intermediate are reacted in copper iodide and cesium carbonate to obtain a fourth intermediate as shown in formula (V);

[0034] Under nitrogen protection, the fourth intermediate, Pd(OAc)2, tricyclohexylphosphine tetrafluoroborate and potassium carbonate are reacted to obtain a fifth intermediate as shown in formula (VI);

[0035] reacting the fifth intermediate, raw material E, palladium catalyst, phosphine ligand and sodium tert-butoxide to obtain a luminescent auxiliary material;

[0036]

[0037] Wherein, m and n are selected from 0 or 1, and cannot be 0 or 1 at the same time;

[0038] X is independently selected from -O-, -S-, -SO2-, -C(R5R6)-, -N(R7)-, -Si(R8R9)-, -Sn(R 10 R 11 )-or-Ge(R 12 R 13 )-;

[0039] L1 and L2 are a linking bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group;

[0040] R1-R4 are each independently selected from hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, amino, silyl, borane, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted 3-30-membered heterocycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted 3-20-membered heteroaryl, substituted or unsubstituted 3-25-membered heteroarylamine, substituted or unsubstituted C6-C60 arylamine, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C6-C60 aryloxy;

[0041] R5~R 13 each independently selected from a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted 3-20-membered heterocycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted 3-30-membered heteroaryl group, a substituted or unsubstituted 3-30-membered heteroarylamino group, and a substituted or unsubstituted (C6-C60)arylamino group;

[0042] Ar1 to Ar4 are each independently selected from a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted 3-20-membered heterocycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted 3-30-membered heteroaryl group, a substituted or unsubstituted 3-15-membered heteroarylamine group, and a substituted or unsubstituted C6-C60 arylamine group.

[0043] The present application also provides an organic electroluminescent device, comprising an anode, a hole injection layer, a hole transport layer, a luminescence auxiliary layer, a luminescent layer, an electron transport layer, an electron injection layer, a cathode and a light extraction layer stacked in sequence, wherein the luminescence auxiliary layer comprises the luminescence auxiliary material or the luminescence auxiliary material prepared by the preparation method.

[0044] The present invention provides a luminescence auxiliary material, wherein the heterocyclic luminescence auxiliary material is coordinated by different heterocyclic ligands so that the compound has different rigidity properties; in addition, the amine unit of the luminescence auxiliary material has a low ionization potential, good electron-donating property, and high hole mobility; at the same time, the symmetry of the molecule is reduced, the conformational isomers of the molecule are increased, and the compound has a rigid planar structure, while the molecular weight is increased, so that the molecules are not easy to crystallize or aggregate, and the material has high photothermal stability. Therefore, after the luminescence auxiliary material of the present application is used in an organic electroluminescent device, the luminous efficiency of the device is improved, the life is delayed, and the driving voltage is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1This is the H-NMR spectrum of the luminescence auxiliary material prepared in Example 1 of the present invention;

[0046] Figure 2 This is the H-NMR spectrum of the luminescence auxiliary material prepared in Example 2 of the present invention;

[0047] Figure 3 This is the H-NMR spectrum of the luminescence auxiliary material prepared in Example 3 of the present invention;

[0048] Figure 4 This is the H-NMR spectrum of the luminescence auxiliary material prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0049] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0050] In view of the unsatisfactory stability, luminous efficiency and lifespan of organic electroluminescent devices in the prior art, the present application provides a luminescent auxiliary material, a preparation method thereof, and an organic electroluminescent device. The device has excellent thermal stability, good luminous efficiency and long service life due to the introduction of the luminescent auxiliary material. Specifically, the embodiment of the present invention discloses a luminescent auxiliary material as shown in formula (I), characterized in that:

[0051]

[0052] Wherein, m and n are selected from 0 or 1, and cannot be 0 or 1 at the same time;

[0053] X is independently selected from -O-, -S-, -SO2-, -C(R5R6)-, -N(R7)-, -Si(R8R9)-, -Sn(R 10 R 11 )-or-Ge(R 12 R 13 )-;

[0054] L1 and L2 are a linking bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group;

[0055] R1-R4 are each independently selected from hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, amino, silyl, borane, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted 3-30-membered heterocycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted 3-20-membered heteroaryl, substituted or unsubstituted 3-25-membered heteroarylamine, substituted or unsubstituted C6-C60 arylamine, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C6-C60 aryloxy;

[0056] R5~R 13 each independently selected from a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted 3-20-membered heterocycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted 3-30-membered heteroaryl group, a substituted or unsubstituted 3-30-membered heteroarylamino group, and a substituted or unsubstituted (C6-C60)arylamino group;

[0057] Ar1 to Ar4 are each independently selected from a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted 3-20-membered heterocycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted 3-30-membered heteroaryl group, a substituted or unsubstituted 3-15-membered heteroarylamine group, and a substituted or unsubstituted C6-C60 arylamine group.

[0058] In the present application, the heteroatom in the above-mentioned heteroaryl and heterocycloalkyl groups is selected from oxygen, nitrogen or sulfur.

[0059] The luminescence auxiliary material described in the present application is more specifically as shown in formula (I-1) or formula (I-2);

[0060]

[0061] In a specific embodiment, R5~R 13 Each is independently selected from a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C20 aryl group, or a substituted or unsubstituted 3-20-membered heteroaryl group, wherein the heteroatom in the heteroaryl group is selected from O, N or S; more specifically, X independently represents -O-, -S-, -C(R5R6)-, or -N(R7)-; in this case, more specifically, R5-R7 are each independently selected from a methyl group, an ethyl group, a phenyl group or a methylbenzene group.

[0062] More specifically, L1 and L2 are independently selected from a linker, a substituted or unsubstituted C6-C18 arylene group, or a substituted or unsubstituted 3- to 18-membered heteroarylene group. In a specific embodiment, L1 and L2 are independently selected from a linker, a phenyl group, a biphenyl group, or a naphthyl group.

[0063] In a specific embodiment, R1 to R4 are each independently hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C6 to C20 aryl, substituted or unsubstituted 3-15 membered heteroaryl, wherein the heteroatom in the heteroaryl is selected from O, N or S; R5 to R 13 Each is independently selected from a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C20 aryl group, or a substituted or unsubstituted 3-20-membered heteroaryl group, wherein the heteroatom in the heteroaryl group is selected from O, N, or S. More specifically, R1-R4 are each independently selected from hydrogen, deuterium, halogen, cyano, pyridyl, or phenyl.

[0064] Ar1 to Ar4 are each independently selected from a substituted or unsubstituted C6 to C25 aryl group, a substituted or unsubstituted 3- to 20-membered heteroaryl group, a substituted or unsubstituted 3- to 10-membered heteroarylamine group, or a substituted or unsubstituted C6 to C30 arylamine group. More specifically, Ar1 to Ar6 are independently selected from the following structures:

[0065]

[0066]

[0067] This application also provides a method for preparing the above auxiliary material, comprising the following steps:

[0068] Under nitrogen protection, raw material A and raw material B are reacted in a palladium catalyst, a phosphine ligand and sodium tert-butoxide to obtain a first intermediate as shown in formula (II);

[0069] Reacting raw material C and raw material D in the presence of copper iodide and potassium sulfate to obtain a second intermediate as shown in formula (III);

[0070] The second intermediate, Pd(OAc), PCy3 and K2CO3 are reacted to obtain a third intermediate as shown in formula (IV);

[0071] Under nitrogen protection, the third intermediate and the first intermediate are reacted in copper iodide and cesium carbonate to obtain a fourth intermediate as shown in formula (V);

[0072] Under nitrogen protection, the fourth intermediate, Pd(OAc)2, tricyclohexylphosphine tetrafluoroborate and potassium carbonate are reacted to obtain a fifth intermediate as shown in formula (VI);

[0073] reacting the fifth intermediate, raw material E, palladium catalyst, phosphine ligand and sodium tert-butoxide to obtain a luminescent auxiliary material;

[0074]

[0075] Wherein, m and n are selected from 0 or 1, and cannot be 0 or 1 at the same time;

[0076] X is independently selected from -O-, -S-, -SO2-, -C(R5R6)-, -N(R7)-, -Si(R8R9)-, -Sn(R 10 R 11 )-or-Ge(R 12 R 13 )-;

[0077] L1 and L2 are each independently selected from a linking bond, a substituted or unsubstituted arylene group, or a substituted or unsubstituted heteroarylene group;

[0078] R1-R4 are each independently selected from hydrogen, deuterium, halogen, cyano, carboxyl, nitro, hydroxyl, amino, silyl, borane, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted 3-30-membered heterocycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted 3-20-membered heteroaryl, substituted or unsubstituted 3-25-membered heteroarylamine, substituted or unsubstituted C6-C60 arylamine, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C6-C60 aryloxy;

[0079] R5~R 13 each independently selected from a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted 3-20-membered heterocycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted 3-30-membered heteroaryl group, a substituted or unsubstituted 3-30-membered heteroarylamino group, and a substituted or unsubstituted (C6-C60)arylamino group;

[0080] Ar1 to Ar4 are each independently selected from a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted 3-20-membered heterocycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted 3-30-membered heteroaryl group, a substituted or unsubstituted 3-15-membered heteroarylamine group, and a substituted or unsubstituted C6-C60 arylamine group.

[0081] The above synthesis process is specifically as follows:

[0082]

[0083] In the above technical solution, the step 1 specifically includes the following steps:

[0084] Under nitrogen protection, raw material A (1.0 eq) and raw material B (1.0 eq) were dissolved in a toluene solution, tris(dibenzylideneacetone)dipalladium (0.01 eq), tri-tert-butylphosphine (0.05 eq) and sodium tert-butoxide (2.0 eq) were added, stirred evenly, heated to 90° C., and refluxed for 5 hours. After the reaction was completed, the temperature was slightly lowered to 75° C., filtered using diatomaceous earth to remove salt and catalyst, and the filtrate was cooled to room temperature and washed three times with water. The organic phase was retained, and the aqueous phase was then extracted with ethyl acetate; after the organic phases were combined, they were dried using anhydrous magnesium sulfate and the solvent was removed using a rotary evaporator to obtain a solid organic matter; the solid organic matter was completely dissolved using dichloromethane, and then slowly added dropwise to a petroleum ether solution, stirred evenly, a precipitate was precipitated, and the solid was filtered off, washed with anhydrous ethanol and petroleum ether in sequence, and dried to obtain intermediate 1;

[0085] In the above technical solution, the step 2 specifically includes the following steps:

[0086] Raw materials C (1.0 eq) and D (1.2 eq) were dissolved in dimethylacetamide, and copper iodide (1.0 eq) and K3PO4 (3.0 eq) were added. The temperature was raised to 110°C and refluxed with stirring. After the reaction was completed, the solution was cooled to room temperature, and the copper was first filtered and removed. The solution containing the product was decompressed to remove all the solvent, and then completely dissolved in CHCl3, washed with water, and the solvent was removed under reduced pressure again. The product was rinsed with anhydrous ethanol and petroleum ether, and dried to obtain intermediate 2.

[0087] In the above technical solution, step 3 specifically includes the following steps:

[0088] Intermediate 2 (1.0 eq), Pd(OAc) (0.1 eq), PCy3 (0.1 eq), and K2CO3 (2.0 eq) were dissolved in dimethylacetamide solution, heated to 150°C and stirred for 20 hours, and the solvent was concentrated under reduced pressure to obtain a solid. The solid organic matter was completely dissolved in dichloromethane, which was then slowly added dropwise to a petroleum ether solution and stirred evenly. A precipitate was precipitated, which was filtered to obtain a solid, washed with anhydrous ethanol and petroleum ether, and dried to obtain intermediate 3.

[0089] In the above technical solution, step 4 specifically includes the following steps:

[0090] Under nitrogen protection, intermediate 3 (1.0 eq) and intermediate 1 (5.0 eq) were dissolved in N,N-dimethyl sulfoxide solution, copper iodide (2.0 eq) and Cs2CO3 (5.0 eq) were added, heated to 150°C, stirred evenly, and reacted for 24 hours. After the reaction was completed, water was added, the precipitate was filtered out, the organic phase was collected, and anhydrous magnesium sulfate was added to dry it. The solvent was removed by rotary evaporation, and the solid organic matter was added to ethanol solution, heated to 80°C, and stirred for 5 hours. After the solution was cooled to room temperature, the solution was filtered to obtain a solid, which was then rinsed with petroleum ether and dried to prepare intermediate 4;

[0091] In the above technical solution, the step 5 specifically includes the following steps:

[0092] Under nitrogen protection, intermediate 4 (1.0 eq) was dissolved in N,N-dimethylacetamide solution, and Pd(OAc)2 (0.10 eq), tricyclohexylphosphine tetrafluoroborate (0.20 eq) and potassium carbonate (4.0 eq) were added and stirred evenly. The temperature was raised to 100°C and refluxed for 12 h. After the reaction was completed, the solution was cooled to room temperature, water was added, and the precipitate was filtered out and dried with anhydrous magnesium sulfate. The solvent was removed using a rotary evaporator to obtain a solid organic matter. The solid organic matter was completely dissolved in dichloromethane, and then slowly added dropwise to a petroleum ether solution and stirred evenly. A precipitate was precipitated and filtered to obtain a solid. The solid was washed with anhydrous ethanol and petroleum ether in sequence and dried to obtain intermediate 5.

[0093] In the above technical solution, step 6 specifically includes the following steps:

[0094] Under nitrogen protection, intermediate 5 (1.0 eq) and raw material E (1.0 eq) were dissolved in a toluene solution, and tris(dibenzylideneacetone)dipalladium (0.01 eq), tri-tert-butylphosphine (0.05 eq) and sodium tert-butoxide (2.0 eq) were added, stirred evenly, heated to 90° C., and refluxed for 5 h. After the reaction, the temperature was slightly lowered to 75° C. and filtered using diatomaceous earth to remove salt and catalyst. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase, and then the aqueous phase was extracted with ethyl acetate. After the organic phases were combined, they were dried over anhydrous magnesium sulfate and the solvent was removed using a rotary evaporator. The remaining substance was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane:V petroleum ether = 10:4) to obtain Chemical Formula 1.

[0095] The present application also provides an organic electroluminescent device, comprising an anode, a hole injection layer, a hole transport layer, a luminescence auxiliary layer, a luminescent layer, an electron transport layer, an electron injection layer, a cathode and a light extraction layer stacked in sequence, wherein the luminescence auxiliary layer includes the luminescence auxiliary material described in the above scheme.

[0096] An embodiment of the present invention further provides an organic electroluminescent device, comprising a first electrode, a second electrode, and at least one organic layer disposed between the first electrode and the second electrode.

[0097] The organic material layer of the organic light-emitting device of the present disclosure may be formed into a single-layer structure, but may also be formed into a multilayer structure having two or more organic material layers. For example, the organic light-emitting device disclosed in the present disclosure may have a structure including a hole injection layer, a hole transport layer, a hole injection and transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, a hole blocking layer, an electron injection and transport layer, etc. as organic material layers. However, the structure of the organic light-emitting device is not limited thereto and may include a smaller number of organic material layers or a larger number of organic material layers.

[0098] The organic electroluminescent device provided by the present invention can be applied to an organic light emitting device (OLED), an organic solar cell (OSC), electronic paper (e-paper), an organic photoreceptor (OPC) or an organic thin film transistor (OTFT).

[0099] The present invention provides a heterocyclic luminescent auxiliary material. By coordinating different heterocyclic ligands, the compound has different rigidity properties. Furthermore, the amine unit on the complex has a low ionization potential, good electron-donating properties, and high hole mobility. At the same time, the symmetry of the molecule is reduced, the number of conformers is increased, and the compound has a rigid planar structure. At the same time, the molecular weight is increased, making it difficult for the molecules to crystallize and aggregate, and the material has high photothermal stability. Therefore, the luminescent auxiliary material provided by the present application, when used in an organic electroluminescent device, improves the luminous efficiency of the device, extends its life, and reduces the driving voltage.

[0100] In order to further understand the present invention, the luminescence auxiliary material provided by the present invention is described in detail below with reference to the embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0101]

[0102] The raw material C-2 (30.00 mmol) and the raw material D-2 (36.00 mmol) were dissolved in 150.00 ml of dimethylacetamide, and copper iodide (30.00 mmol) and K3PO4 (90.00 mmol) were added. The temperature was raised to 110°C and refluxed with stirring. After the reaction was completed, the solution was cooled to room temperature, and the copper was filtered and removed. The solution containing the product was decompressed and all the solvent was removed. The product was completely dissolved with CHCl3, washed with water, and the solvent was removed under reduced pressure again. The product was washed with anhydrous ethanol and petroleum ether in sequence, and dried to obtain intermediate 2-2 (7.51 g, yield: 67.21%).

[0103] Intermediate 2-2 (18.78 mmol), Pd(OAc) (0.19 mmol), PCy3 (0.19 mmol), and K2CO3 (37.56 mmol) were dissolved in 70.00 ml of dimethylacetamide solution, heated to 150°C and stirred for 20 hours, and the solvent was concentrated under reduced pressure to obtain a solid. The solid organic matter was completely dissolved in dichloromethane, and then slowly added dropwise to a petroleum ether solution and stirred evenly. A precipitate was precipitated, and the solid was filtered off. The solid was washed with anhydrous ethanol and petroleum ether in sequence and dried to obtain intermediate 3-2 (2.97 g, yield: 53.87%).

[0104] According to the above preparation method, the intermediate compounds shown in the following table were prepared for use in the following Examples 1 to 4;

[0105] Table 1 Structural data of intermediates in Examples 2 to 4

[0106]

[0107]

[0108] Example 1: Preparation of Compound-2

[0109] Under nitrogen protection, intermediate 3-2 (10.00 mmol) and raw material A-2 (50.00 mmol) were dissolved in 120.00 ml N, N-dimethyl sulfoxide solution, copper iodide (20.00 mmol) and Cs2CO3 (50.00 mmol) were added, heated to 150 ° C, stirred evenly, and reacted for 24 hours. After the reaction was completed, water was added, the precipitate was filtered out, the organic phase was collected, anhydrous magnesium sulfate was added and dried, the solvent was removed by rotary evaporation, the solid organic matter was added to ethanol solution, the temperature was raised to 80 ° C, and stirred for 5 hours. After the solution was cooled to room temperature, the solution was filtered to obtain a solid, which was then rinsed with petroleum ether and dried to prepare intermediate 4 (1.60 g, yield: 38.6%);

[0110]

[0111] Under nitrogen protection, intermediate 4 (3.96 mmol) was dissolved in 16.00 ml of N,N-dimethylacetamide solution, and Pd(OAc)2 (0.40 mmol), tricyclohexylphosphine tetrafluoroborate (0.79 mmol) and potassium carbonate (15.84 mmol) were added and stirred evenly. The temperature was raised to 100°C and refluxed for 12 h. After the reaction was completed, the solution was cooled to room temperature, water was added, and the precipitate was filtered out and dried over anhydrous magnesium sulfate. The solvent was removed using a rotary evaporator to obtain a solid organic matter. The solid organic matter was completely dissolved in dichloromethane, and then slowly added dropwise to a petroleum ether solution and stirred evenly. A precipitate was precipitated and filtered to obtain a solid. The solid was washed with anhydrous ethanol and petroleum ether in sequence and dried to obtain intermediate 5 (1.45 g, yield: 46.7%).

[0112]

[0113] Under nitrogen protection, intermediate 5 (3.83 mmol) and raw material E-2 (3.83 mmol) were dissolved in 130.00 ml of toluene solution, tris(dibenzylideneacetone)dipalladium (0.04 mmol), tri-tert-butylphosphine (0.19 mmol) and sodium tert-butoxide (7.66 mmol) were added, stirred evenly, heated to 90 ° C, and refluxed for 5 h; after the reaction, the temperature was slightly lowered to 75 ° C, filtered using diatomaceous earth to remove salt and catalyst, and the filtrate was cooled to room temperature and washed three times with water to retain the organic phase, and then the aqueous phase was extracted with ethyl acetate; after the organic phases were combined, they were dried over anhydrous magnesium sulfate and the solvent was removed using a rotary evaporator; the remaining substance was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane: V petroleum ether = 10:4) to obtain compound-2 (2.49 g, yield: 86.4%, Mw: 750.91).

[0114]

[0115] The obtained compound-2 was tested and analyzed, and the results were as follows: HPLC purity: >99%; mass spectrometry test: theoretical value 750.90; test value 750.91; elemental analysis: calculated value: C, 89.57; H, 4.56; N, 3.73; O, 2.13; test value: C, 89.56; H, 4.57; N, 3.74; O, 2.12; nuclear magnetic resonance spectroscopy: as Figure 1 shown.

[0116] Example 2: Preparation of Compound-95

[0117] Under nitrogen protection, intermediate 3-95 (15.00 mmol) and raw material A-95 (75.00 mmol) were dissolved in 210.00 ml N, N-dimethyl sulfoxide solution, copper iodide (30.00 mmol) and Cs2CO3 (75.00 mmol) were added, heated to 150 ° C, stirred evenly, and reacted for 24 hours. After the reaction was completed, water was added, the precipitate was filtered out, the organic phase was collected, and anhydrous magnesium sulfate was added to dry it. The solvent was removed by rotary evaporation, and the solid organic matter was added to ethanol solution, heated to 80 ° C, and stirred for 5 hours. After the solution was cooled to room temperature, the solution was filtered to obtain a solid, which was then rinsed with petroleum ether and dried to prepare intermediate 4 (2.42 g, yield: 38.4%).

[0118]

[0119] Under nitrogen protection, intermediate 4 (5.71 mmol) was dissolved in 25.00 ml of N,N-dimethylacetamide solution, and Pd(OAc)2 (0.57 mmol), tricyclohexylphosphine tetrafluoroborate (1.14 mmol) and potassium carbonate (22.84 mmol) were added and stirred evenly. The temperature was raised to 100°C and refluxed for 12 h. After the reaction was completed, the solution was cooled to room temperature, water was added, and the precipitate was filtered out and dried over anhydrous magnesium sulfate. The solvent was removed using a rotary evaporator to obtain a solid organic matter. The solid organic matter was completely dissolved in dichloromethane, and then slowly added dropwise to a petroleum ether solution and stirred evenly. A precipitate was precipitated and filtered to obtain a solid. The solid was washed with anhydrous ethanol and petroleum ether in sequence and dried to obtain intermediate 5 (1.02 g, yield: 46.6%).

[0120]

[0121] Under nitrogen protection, intermediate 5 (2.62 mmol) and raw material E-95 (2.62 mmol) were dissolved in 80.00 ml of toluene solution, and tris(dibenzylideneacetone)dipalladium (0.03 mmol), tri-tert-butylphosphine (0.13 mmol) and sodium tert-butoxide (5.24 mmol) were added, stirred evenly, heated to 90°C, and refluxed for 5 h; after the reaction, the temperature was slightly lowered to 75°C, filtered using diatomaceous earth to remove salt and catalyst, and the filtrate was cooled to room temperature and washed three times with water, retaining the organic phase, and then the aqueous phase was extracted with ethyl acetate; after the organic phases were combined, they were dried over anhydrous magnesium sulfate and the solvent was removed using a rotary evaporator; the remaining substance was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane: V petroleum ether = 10:4) to obtain compound-95 (1.60 g, yield: 86.7%, Mw: 706.92).

[0122]

[0123] The obtained compound-95 was tested and analyzed, and the results were as follows: HPLC purity: >99%; mass spectrometry test: theoretical value 706.91; test value 706.92; elemental analysis: calculated value: C, 86.65; H, 4.85; N, 3.96; S, 4.54; test value: C, 86.66; H, 4.84; N, 3.95; S, 4.55; nuclear magnetic resonance spectroscopy: as Figure 2 shown.

[0124] Example 3: Preparation of Compound-128

[0125] Under nitrogen protection, intermediate 3-128 (15.00 mmol) and raw material A-128 (75.00 mmol) were dissolved in 250.00 ml N, N-dimethyl sulfoxide solution, copper iodide (30.00 mmol) and Cs2CO3 (75.00 mmol) were added, heated to 150 ° C, stirred evenly, and reacted for 24 hours. After the reaction was completed, water was added, the precipitate was filtered out, the organic phase was collected, and anhydrous magnesium sulfate was added to dry it. The solvent was removed by rotary evaporation, and the solid organic matter was added to ethanol solution, heated to 80 ° C, and stirred for 5 hours. After the solution was cooled to room temperature, the solution was filtered to obtain a solid, which was then rinsed with petroleum ether and dried to prepare intermediate 4 (2.49 g, yield: 38.6%).

[0126]

[0127] Under nitrogen protection, intermediate 4 (5.58 mmol) was dissolved in 25.00 ml of N,N-dimethylacetamide solution, and Pd(OAc)2 (0.56 mmol), tricyclohexylphosphine tetrafluoroborate (1.11 mmol) and potassium carbonate (22.32 mmol) were added and stirred evenly. The temperature was raised to 100°C and refluxed for 12 h. After the reaction was completed, the solution was cooled to room temperature, water was added, and the precipitate was filtered out and dried over anhydrous magnesium sulfate. The solvent was removed using a rotary evaporator to obtain a solid organic matter. The solid organic matter was completely dissolved in dichloromethane, and then slowly added dropwise to a petroleum ether solution and stirred evenly. A precipitate was precipitated and filtered to obtain a solid. The solid was washed with anhydrous ethanol and petroleum ether in sequence and dried to obtain intermediate 5 (1.02 g, yield: 46.8%).

[0128]

[0129] Under nitrogen protection, intermediate 5 (2.55 mmol) and raw material E-128 (2.55 mmol) were dissolved in 18.00 ml of toluene solution, tris(dibenzylideneacetone)dipalladium (0.03 mmol), tri-tert-butylphosphine (0.13 mmol) and sodium tert-butoxide (5.10 mmol) were added, stirred evenly, heated to 90 ° C, and refluxed for 5 h; after the reaction, the temperature was slightly lowered to 75 ° C, filtered through diatomaceous earth to remove salt and catalyst, and the filtrate was cooled to room temperature and washed three times with water, retaining the organic phase, and then the aqueous phase was extracted with ethyl acetate; after the organic phases were combined, they were dried over anhydrous magnesium sulfate and the solvent was removed using a rotary evaporator; the remaining material was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane: V petroleum ether = 10:4) to obtain compound-128 (1.56 g, yield: 86.8%, Mw: 706.92);

[0130]

[0131] The obtained compound-128 was tested and analyzed, and the results were as follows: HPLC purity: >99%; mass spectrometry test: theoretical value 706.91; test value 706.92; elemental analysis: calculated value: C, 86.65; H, 4.85; N, 3.96; S, 4.54; test value: C, 86.66; H, 4.84; N, 3.97; S, 4.53; nuclear magnetic resonance spectroscopy: as Figure 3 shown.

[0132] Example 4: Preparation of Compound-146

[0133] Under nitrogen protection, intermediate 3-146 (15.00 mmol) and raw material A-146 (75.00 mmol) were dissolved in 220.00 ml N, N-dimethyl sulfoxide solution, copper iodide (30.00 mmol) and Cs2CO3 (75.00 mmol) were added, heated to 150 ° C, stirred evenly, and reacted for 24 hours. After the reaction was completed, water was added, the precipitate was filtered out, the organic phase was collected, and anhydrous magnesium sulfate was added to dry it. The solvent was removed by rotary evaporation, and the solid organic matter was added to ethanol solution, heated to 80 ° C, and stirred for 5 hours. After the solution was cooled to room temperature, the solution was filtered to obtain a solid, which was then rinsed with petroleum ether and dried to prepare intermediate 4 (2.77 g, yield: 38.5%).

[0134]

[0135] Under nitrogen protection, intermediate 4 (5.63 mmol) was dissolved in 27.00 ml of N, N-dimethylacetamide solution, and Pd (OAc) 2 (0.56 mmol), tricyclohexylphosphine tetrafluoroborate (1.13 mmol) and potassium carbonate (22.52 mmol) were added and stirred evenly. The temperature was raised to 100 ° C and refluxed for 12 h. After the reaction was completed, the solution was cooled to room temperature, water was added, and the precipitate was filtered and dried with anhydrous magnesium sulfate. The solvent was removed by rotary evaporation to obtain a solid organic matter. The solid organic matter was completely dissolved in dichloromethane, and then slowly added dropwise to a petroleum ether solution, stirred evenly, and a precipitate was precipitated. The solid was filtered and washed with anhydrous ethanol and petroleum ether in sequence, and dried to obtain intermediate 5 (1.15 g, yield: 46.5%).

[0136]

[0137] Under nitrogen protection, intermediate 5 (2.27 mmol) and raw material E-146 (2.27 mmol) were dissolved in 20.00 ml of toluene solution, and tris(dibenzylideneacetone)dipalladium (0.02 mmol), tri-tert-butylphosphine (0.11 mmol) and sodium tert-butoxide (4.54 mmol) were added, stirred evenly, heated to 90°C, and refluxed for 5 h; after the reaction, the temperature was slightly lowered to 75°C, filtered using diatomaceous earth to remove salt and catalyst, and the filtrate was cooled to room temperature and washed three times with water, retaining the organic phase, and then the aqueous phase was extracted with ethyl acetate; after the organic phases were combined, they were dried over anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator; the remaining substance was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V dichloromethane: V petroleum ether = 10:4) to obtain compound-146 (1.73 g, yield: 86.7%, Mw: 878.08).

[0138]

[0139] The obtained compound-146 was tested and analyzed, and the results were as follows: HPLC purity: >99%; mass spectrometry test: theoretical value 878.09; test value 878.08; elemental analysis: calculated value: C, 90.28; H, 4.94; N, 4.79; test value: C, 90.27; H, 4.96; N, 4.78; nuclear magnetic resonance spectroscopy: as Figure 4 shown.

[0140] The synthesis methods of other compounds are the same as those in the above examples and are not described in detail here. The mass spectra and molecular formulas of other synthesis examples are shown in Table 2 below:

[0141] Table 2 Structural formula data of different luminescent doping materials

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148] The glass transition temperature (tg) of the compounds synthesized in the above examples was tested using TMA4000, as shown in Table 3:

[0149] Table 3 Glass transition temperature data of different luminescent doping compounds

[0150] Compound Glass transition temperature (tg) Compound Glass transition temperature (tg) 1 161.7 89 162.5 2 161.4 91 163.6 16 162.0 94 162.2 17 161.9 95 163.8 20 161.6 100 161.8 39 163.0 125 161.5 41 162.9 127 161.0 42 163.2 128 161.2 43 163.4 131 162.1 44 163.5 136 163.7 50 162.7 137 159.4 54 162.6 139 160.0 61 163.1 141 159.8 62 162.8 145 159.6 63 163.3 146 160.5

[0151] It can be seen from Table 2 that the hole transport material disclosed in the present invention has good thermal stability.

[0152] The organic electroluminescent device prepared by using the luminescence auxiliary material provided in the above embodiment includes an anode, a hole injection layer, a hole transport layer, a luminescence auxiliary layer, a luminescent layer, an electron transport layer, an electron injection layer, and a cathode.

[0153] When the organic layer includes a hole transport layer, the hole transport layer includes the hole transport material provided in the above embodiment.

[0154] Device Example 1:

[0155] The structure of the prepared OLED device is: ITO anode / HIL / HTL / luminescence auxiliary layer / EML / ETL / EIL / cathode / light extraction layer;

[0156] a. ITO anode: the coating thickness is The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate was cleaned twice in distilled water, ultrasonically washed for 30 minutes, and then repeatedly cleaned twice with distilled water, ultrasonically washed for 10 minutes. After washing, it was ultrasonically washed with methanol, acetone, and isopropanol in sequence (each washing for 5 minutes), dried, and then transferred to a plasma cleaning machine for washing for 5 minutes. It was then sent to a vapor deposition machine, and other functional layers were sequentially vapor-deposited on it with the substrate as the anode;

[0157] b. HIL (hole injection layer): Vacuum-deposit the hole injection layer materials H-1 and P-dopant, whose chemical formula is shown below. The mass ratio of H-1 to P-dopant is 97:3, and the thickness is 10 nm.

[0158] c. HTL (hole transport layer): 130 nm of H-1 was vacuum-deposited on the hole injection layer as a hole transport layer;

[0159] d. Luminescence auxiliary layer: vacuum-deposit 10 nm of the compound 2 provided in the above embodiment on the hole transport layer as a luminescence auxiliary layer;

[0160] e. EML (Emitting Layer): A host material and a dopant material are then vacuum-deposited on the auxiliary light-emitting layer to a thickness of 20 nm to form the EML. The chemical formulas of the host and dopant are shown below. The weight ratio of the host material to the dopant is 98:2.

[0161] f. ETL (Electron Transport Layer): ET-1 and Liq were evaporated to a thickness of 35 nm as the electron transport layer. The chemical formula of ET-1 is shown below. The weight ratio of ET-1 to Liq is 50:50.

[0162] g. EIL (electron injection layer): 1.0 nm Yb was evaporated to form an electron injection layer;

[0163] h. Cathode: 18 nm of magnesium and silver were evaporated at a weight ratio of 1:9 to obtain an OLED device;

[0164] i. Light extraction layer: C-1 was vacuum-evaporated to a thickness of 70 nm on the cathode to serve as a light extraction layer.

[0165]

[0166] Referring to the method provided in the above device embodiment 1, compounds 1, 16, 17, 20, 39, 41, 42, 43, 44, 50, 54, 61, 62, 63, 89, 91, 94, 95, 100, 125, 127, 128, 131, 136, 137, 139, 141, 145, and 146 were respectively selected to replace compound 2 for evaporation of the light-emitting auxiliary layer, and the corresponding organic electroluminescent devices were prepared, which are respectively recorded as device embodiments 2 to 30.

[0167] Device Comparison Example 1:

[0168] This comparative example provides an organic electroluminescent device. The only difference between the preparation method of the organic electroluminescent device and that of Device Example 1 is that the organic electroluminescent device uses an existing comparative compound 1 instead of the luminescent auxiliary material (Compound 2) in the above Device Example 1 for vapor deposition to prepare the corresponding organic electroluminescent device, which is recorded as Device Comparative Example 1. The chemical structure of the comparative compound 1 is:

[0169]

[0170] The driving voltage, luminous efficiency and life of the organic electroluminescent devices obtained from the above device examples 1 to 30 and the device comparative example 1 were characterized at a brightness of 15000 (nits). The test results are shown in Table 4 below:

[0171] Table 4 Performance data of organic electroluminescent devices prepared in Examples and Comparative Examples

[0172]

[0173]

[0174] As can be seen from Table 3 above, the organic electroluminescent device prepared using the organic electroluminescent compound provided by the present invention as the luminescent auxiliary layer has a lower starting voltage than the organic electroluminescent device prepared using the comparative compound as the luminescent auxiliary layer, and the luminous efficiency and life are significantly improved.

[0175] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0176] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A luminescence auxiliary material as shown in formula (I), characterized in that: Wherein, m and n are each independently selected from 0 or 1, and cannot be 0 or 1 at the same time; X is independently selected from -O-, -S-, and -N(R7)-; L1 and L2 are each independently selected from a linking bond, an unsubstituted C6-C18 arylene group; R1 to R4 are each independently selected from hydrogen, unsubstituted C6 aryl; R7 is independently selected from phenyl; Ar1 to Ar4 are each independently selected from the following structures:

2. The luminescence auxiliary material according to claim 1, characterized in that The luminescence auxiliary material is specifically:

3. The method for preparing the luminescence auxiliary material according to claim 1, comprising the following steps: Under nitrogen protection, raw material A and raw material B are reacted in a palladium catalyst, a phosphine ligand and sodium tert-butoxide to obtain a first intermediate as shown in formula (II); Reacting raw material C and raw material D in the presence of copper iodide and potassium sulfate to obtain a second intermediate as shown in formula (III); The second intermediate, Pd(OAc), PCy3 and K2CO3 are reacted to obtain a third intermediate as shown in formula (IV); Under nitrogen protection, the third intermediate and the first intermediate are reacted in copper iodide and cesium carbonate to obtain a fourth intermediate as shown in formula (V); Under nitrogen protection, the fourth intermediate, Pd(OAc)2, tricyclohexylphosphine tetrafluoroborate and potassium carbonate are reacted to obtain a fifth intermediate as shown in formula (VI); reacting the fifth intermediate, raw material E, palladium catalyst, phosphine ligand and sodium tert-butoxide to obtain a luminescent auxiliary material; Wherein, m and n are each independently selected from 0 or 1, and cannot be 0 or 1 at the same time; X is independently selected from -O-, -S-, and -N(R7)-; L1 and L2 are each independently selected from a linking bond, an unsubstituted C6-C18 arylene group; R1 to R4 are each independently selected from hydrogen, unsubstituted C6 aryl; R7 are each independently selected from phenyl; Ar1 to Ar4 are each independently selected from the following structures:

4. An organic electroluminescent device, comprising an anode, a hole injection layer, a hole transport layer, a luminescence-assisting layer, a luminescent layer, an electron transport layer, an electron injection layer, a cathode and a light extraction layer stacked in sequence, wherein the luminescence-assisting layer comprises the luminescence-assisting material according to any one of claims 1 to 2 or the luminescence-assisting material prepared by the preparation method according to claim 3.

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