Host material, preparation method thereof, light-emitting layer material and organic electroluminescent device

Abstract

The present application relates to the technical field of organic electroluminescent material, in particular to a host material, a preparation method thereof, a light-emitting layer material and an organic electroluminescent device.The host material is selected from the compounds shown in the following general formula I: wherein m and n are independently selected from integers of 0 or 1, and m and n are not 0 at the same time; when m is not 0, L represents a connecting bond or a substituted or unsubstituted C6-C24 arylene; when m is 0, L represents a substituted or unsubstituted C6-C24 aryl; when Ar exists, it represents a substituted or unsubstituted C6-C30 aryl or a substituted or unsubstituted C6-C30 heteroaryl fused on a benzene ring, and the heteroatom contains at least one of O, S, N, Si and Se.The host material solves the problems of poor solubility and lack of film-forming property of the existing light-emitting material, and improves the performance of the light-emitting material in the device life and luminous efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic electroluminescent materials, in particular to a host material, a preparation method thereof, a light-emitting layer material and an organic electroluminescent device. BACKGROUND

[0002] An organic light-emitting device converts electrical energy into light by applying electrical power to an organic electroluminescent material, and generally includes an anode, a cathode, and an organic layer formed between or outside the two electrodes. The organic layer can include a hole injection layer, a hole transport layer, a hole auxiliary layer, a light-emitting auxiliary layer, an electron blocking layer, a light-emitting layer, an electron buffer layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cover layer.

[0003] In order to manufacture an organic light-emitting device in the related art, a deposition method is generally used. However, there is a problem of material loss in manufacturing an organic light-emitting device using a deposition method, and in order to solve this problem, a technology for manufacturing a device by improving production efficiency by reducing the loss of materials using a solution method has been developed, and a material that can be used during the solution method has been developed.

[0004] A material used in manufacturing an organic light-emitting device using a solution method needs to have the characteristics described below. First, a material used in an organic light-emitting device needs to be able to form a uniform solution that can be stored. Since a commercialized material for a deposition method has good crystallinity, the material cannot be well dissolved in a solution, or even if the material forms a solution, it is easy to form crystals thereof, and as the storage time, the concentration gradient of the solution is likely to change, or a defective device is likely to be formed. Second, a material for a solution method needs to be excellent in coatability so that a thin film having a uniform thickness can be formed without a hole or aggregation phenomenon occurring during the formation of the thin film, and when an organic light-emitting device is manufactured, the material needs to have excellent current efficiency and excellent lifespan characteristics.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The present application aims to provide a host material, a preparation method thereof, a light-emitting layer material and an organic electroluminescent device. The host material of the present application solves the problems of poor solubility and lack of film-forming property of the existing light-emitting material, and improves the problem of unsatisfactory performance of the light-emitting material in device lifespan and light-emitting efficiency.

[0007] The present application is implemented as follows:

[0008] In a first aspect, the present application provides a host material selected from the following compound represented by the following general formula I:

[0009] wherein m and n are independently selected from an integer of 0 or 1, and m and n cannot be 0 at the same time;

[0010] m is not 0, L represents a connecting bond or a substituted or unsubstituted C6-C24 arylene;

[0011] m is 0, L represents a substituted or unsubstituted C6-C24 aryl;

[0012] Ar is present or not, when Ar is present, it represents a substituted or unsubstituted C6-C30 aryl or a substituted or unsubstituted C6-C30 heteroaryl fused on the benzene ring, and the heteroatom contains at least any one of O, S, N, Si and Se.

[0013] In a second aspect, the present application provides a preparation method of the host material in the above-mentioned embodiments, comprising: synthesizing according to the following synthesis path:

[0014]

[0015] In a third aspect, the present application provides a light-emitting layer material, which comprises a dopant material and the host material in the above-mentioned embodiments.

[0016] In a fourth aspect, the present application provides an organic electroluminescent device, which comprises an organic layer prepared from the light-emitting layer material in the above-mentioned embodiments.

[0017] In an optional embodiment, the organic layer comprises at least one of a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer and an electron injection layer, and the light-emitting layer is prepared from the light-emitting layer material as described above.

[0018] The present application has the following beneficial effects: (1) The host material provided by the embodiment of the present application can improve the electron transport property of the material, promote the improvement of device efficiency by introducing electron-withdrawing groups (for example, dibenzofuran or benzonaphthofuran) on the basis of the anthracene nucleus, and meanwhile, the rigid planar configuration thereof is beneficial to the accumulation and orientation of the material in the process of forming a thin film, realizes efficient energy transfer, and can improve the stability of the compound and further improve the service life of the device. The tetramethyltetralin group introduced on the other side of the anthracene group provides a conjugated electron distribution system of the compound, so that the molecules are effectively and orderly stacked, thereby exerting the best carrier transport and migration under a certain electric field; meanwhile, the position of the substituent group is adjusted to increase the molecular volume and effectively improve the solubility of the material. The aryl group (for example, phenyl or naphthyl) is introduced between the anthracene group and the tetramethyltetralin group in a non-para connection mode (for example, meta or ortho), which on the one hand extends the system through the buffer of the arylene group, thereby improving the molecular fluidity and the luminous efficiency of the device, and on the other hand, the non-para connection mode increases the dihedral angle of the anthracene group and the tetramethyltetralin group, reduces the molecular aggregation and accumulation, and improves the solubility of the compound, which is more conducive to the operation of the device prepared in the later stage.

[0019] (2) The solubility of the compound in the present application is excellent, the blue light emitting host material layer can be prepared by a solution method, the number of times of using a vacuum evaporation device is reduced, the film forming can be performed under atmospheric pressure, and large-area or continuous production can be realized, thereby reducing the manufacturing cost.

[0020] (3) The host material and the blue light doping material can better perform energy transfer, reduce energy loss, realize the light emission of the doping material at about 460 nm, effectively present the characteristics of the blue light emitting layer host material, and the service life and efficiency of the organic electroluminescent device prepared by using the same are also obviously improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0022] Figure 1 The nuclear magnetic resonance hydrogen spectrum of the compound 6 provided by the embodiment 1 of the present application is shown in the following figure:

[0023] Figure 2 The nuclear magnetic resonance hydrogen spectrum of the compound 111 provided by the embodiment 2 of the present application is shown in the following figure:

[0024] Figure 3 The nuclear magnetic resonance hydrogen spectrum of the compound 191 provided by the embodiment 3 of the present application is shown in the following figure. DETAILED DESCRIPTION

[0025] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. If specific conditions are not indicated in the embodiments, the conventional conditions or the conditions suggested by the manufacturers are adopted. If the manufacturers of the reagents or instruments are not indicated, the conventional products that can be purchased in the market are adopted.

[0026] The embodiments of the present application provide a host material selected from the compounds shown in the following general formula I:

[0027] wherein m and n are independently selected from the integers of 0 or 1, and m and n cannot be 0 at the same time; when m is not 0, L represents a connecting bond or a substituted or unsubstituted C6-C24 arylene; when m is 0, L represents a substituted or unsubstituted C6-C24 aryl; Ar can exist or not exist, when Ar does not exist, the group corresponding to n is directly connected to the dibenzofuran is directly connected to the dibenzofuran , and can be connected to any position of the above-mentioned dibenzofuran. When Ar exists, it represents a substituted or unsubstituted C6-C30 aryl or a substituted or unsubstituted C6-C30 heteroaryl fused to the benzene ring, and the heteroatom at least contains one of O, S, N, Si, Se.

[0028] The host material provided by the embodiments of the present application can improve the electron transport property of the material, promote the improvement of the device efficiency by introducing an electron-withdrawing group (for example, dibenzofuran or benzonaphthofuran) on the basis of the anthracene nucleus, and at the same time, it presents a rigid planar configuration, which is beneficial to the accumulation and orientation of the material in the process of forming a thin film, realizes high energy transfer, and can improve the stability of the compound and further improve the service life of the device. The tetramethyltetrahydronaphthyl group introduced on the other side of the anthracene group provides a conjugated electron distribution system of the compound, so that the molecules are effectively and orderly stacked, thereby exerting the best carrier transport and migration under a certain electric field; at the same time, the position of the substituent group is adjusted to increase the molecular volume, thereby effectively improving the solubility of the material. The aryl group (for example, phenyl or naphthyl) is introduced between the anthracene group and the tetramethyltetrahydronaphthyl group in a non-para connection mode (for example, meta or ortho), which on the one hand extends the system through the buffer of the arylene group, thereby improving the molecular fluidity and the luminous efficiency of the device, and on the other hand, the non-para connection mode increases the dihedral angle of the anthracene group and the tetramethyltetrahydronaphthyl group, reduces the molecular aggregation and accumulation, and improves the solubility of the compound, which is more beneficial to the operation of the device made in the later stage.

[0029] Further, when Ar exists, the Ar and the dibenzofuran The benzene ring is fused to any one of the following positions: 1,2; 2,3; and 3,4.

[0030] When Ar is present, it can be selected from substituted or unsubstituted C6-C30 aryl (e.g., phenyl, naphthyl) or substituted or unsubstituted C6-C30 heteroaryl, which contains at least one of O, S, N, Si, Se as a heteroatom.

[0031] Further, when m is not 0, L represents any one of a bond, phenylene, and naphthylene. When m is 0, L is selected from phenyl or naphthyl.

[0032] Further, the host material is selected from any one of the compounds represented by the following general formula I-1 or general formula I-2:

[0033]

[0034] More preferably, the host material is selected from any one of the compounds represented by the following general formula I-a, general formula I-b, general formula I-c, general formula I-d, general formula I-e, general formula I-f, general formula I-g, general formula I-h, general formula I-i, general formula I-j, general formula I-k, and general formula I-l:

[0035]

[0036] The definitions of m, n, and Ar in the above general formula I-1, general formula I-2, general formula I-a, general formula I-b, general formula I-c, general formula I-d, general formula I-e, general formula I-f, general formula I-g, general formula I-h, general formula I-i, general formula I-j, general formula I-k, and general formula I-l are consistent with the definitions in the above general formula I.

[0037] More specifically, the host material is selected from any one of the compounds represented by the following structural formula:

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059] The compound provided by the embodiment of the present application has excellent solubility, and the blue light-emitting host material layer can be prepared by a solution method, the number of vacuum evaporation devices used is reduced, film formation can be performed under atmospheric pressure, and large-area or continuous production is also possible, thereby reducing manufacturing costs.

[0060] The host material provided by the embodiment of the present application can be prepared by a synthesis method known to those skilled in the art. Alternatively, the following reaction scheme is preferably used for preparation.

[0061] In the second aspect, the present application provides a preparation method of the host material according to the above embodiment, comprising: synthesizing according to the following synthesis path:

[0062]

[0063] In particular, for the complex raw material not disclosed, a classical Suzuki coupling reaction is used for synthesis and applied to the present application. The specific preparation process is as follows:

[0064] Step 1 specifically comprises the following steps:

[0065] Into a reaction flask, raw material A (1.0 eq), raw material B (1.1 eq) and potassium carbonate (3.0 eq) were added, followed by a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and the mixture was purged with nitrogen three times. Then, tetrakis(triphenylphosphine)palladium (0.01 eq) was added under nitrogen protection, and the reaction was refluxed at 80-120°C for 4-12 h. The reaction was monitored by thin layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered using diatomite to remove the salt and catalyst. The filtrate was cooled to room temperature, washed with water three times, and the organic phase was retained. Then, the aqueous phase was extracted with dichloromethane. The combined organic phase was concentrated, and the mixture was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:5) to obtain intermediate 1.

[0066] Step 2 specifically includes the following steps:

[0067] Into a reaction flask, intermediate 1 (1.0 eq), raw material C (1.1 eq) and cesium carbonate (2.0 eq) were added, followed by a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and the mixture was purged with nitrogen three times. Then, palladium acetate (0.05 eq) and X-Phos (0.1 eq) were added under nitrogen protection, and the reaction was refluxed at 80-120°C for 4-12 h. The reaction was monitored by thin layer chromatography. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered using diatomite to remove the salt and catalyst. The filtrate was cooled to room temperature, washed with water three times, and the organic phase was retained. Then, the aqueous phase was extracted with dichloromethane. The combined organic phase was concentrated, and the mixture was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:6) to obtain intermediate 2.

[0068] Step 3 specifically includes the following steps:

[0069] Into a reaction flask, intermediate 2 (1.0 eq) and raw material D (1.1 eq) were added, followed by dichloromethane. The mixture was stirred at room temperature for 2-8 h. The reaction was monitored by thin layer chromatography. After the reaction was completed, the mixture was extracted with water three times, and the organic phase was retained. The combined organic phase was concentrated, and the mixture was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:8) to obtain intermediate 3.

[0070] This step is a bromination reaction of an anthracene-containing intermediate with N-bromosuccinimide. L is connected to the para position of the anthracene group, which has active hydrogen, and the substitution degree of bromination at this position is the highest.

[0071] Reference:

[0072] 1. Basic Organic Chemistry (3rd edition, Volume 1), Xing Qiyi, Pei Weiwei, Xu Ruqiu, Pei Jian, Publisher: Higher Education Press, Publication Date: 2005.06, ISBN: 978-7-04-016637-8, pp. 472-473.

[0073] 2. Peng L. Design, synthesis of phenyl-bridged di-anthracene organic deep blue light-emitting materials and their applications in organic electroluminescent devices[D]. South China University of Technology, 2019, 36-38.

[0074] Step 4 specifically includes the following steps:

[0075] The intermediate 3 (1.0 eq), the raw material E (1.1 eq) and potassium carbonate (3.0 eq) are added to a reaction bottle, followed by adding a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and then the reaction bottle is replaced with nitrogen three times. Then, tetrakis(triphenylphosphine)palladium (0.01 eq) is added under nitrogen protection, and the temperature is raised to 80-120°C and refluxed for 4-12 hours. The reaction is detected by thin layer chromatography. After the reaction is completed, the temperature is slightly lowered, and diatomite is used for filtration to remove the salt and catalyst. After the filtrate is cooled to room temperature, it is washed with water three times, and the organic phase is retained. Then, the aqueous phase is extracted with dichloromethane. After the organic phases are combined, they are concentrated, and then purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:5) to obtain the intermediate 4.

[0076] Step 5 specifically includes the following steps:

[0077] The intermediate 4 (1.0 eq), the raw material F (1.1 eq) and cesium carbonate (3.0 eq) are added to a reaction bottle, followed by adding a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and then the reaction bottle is replaced with nitrogen three times. Then, palladium acetate (0.05 eq) and X-Phos (0.1 eq) are added under nitrogen protection, and the temperature is raised to 80-120°C and refluxed for 4-12 hours. The reaction is detected by thin layer chromatography. After the reaction is completed, the temperature is slightly lowered, and diatomite is used for filtration to remove the salt and catalyst. After the filtrate is cooled to room temperature, it is washed with water three times, and the organic phase is retained. Then, the aqueous phase is extracted with dichloromethane. After the organic phases are combined, they are concentrated, and then purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:6) to obtain the general formula I.

[0078] In a third aspect, the present application provides a light-emitting layer material, which comprises a dopant material and a host material according to the above-mentioned embodiments.

[0079] In a fourth aspect, the present application provides an organic electroluminescent device comprising an organic layer prepared from the light-emitting layer material according to the above-mentioned embodiments. The organic layer can include a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, etc. as the structure of the organic layer. However, the structure of the organic light-emitting element is not limited thereto, and can include a smaller or larger number of organic layers. Among them, the light-emitting layer is prepared from the light-emitting layer material described above.

[0080] As for the compound represented by the above general formula I, in the production of an organic light emitting element, an organic layer is formed by a solution coating method. The solution coating method is not limited to, for example, spin coating, dip coating, blade coating, inkjet printing, screen printing, spray coating, roll coating, and the like.

[0081] The organic light emitting element of the present application can be a top emission type, a bottom emission type, or a bidirectional emission type, depending on the materials used.

[0082] As the anode material, a material having a large work function is generally preferred so that holes are smoothly injected into the organic material layer. Specific examples of the anode material that can be used in the present disclosure include metals such as vanadium, chromium, copper, zinc, and gold, or alloys thereof; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SnO2:Sb; conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylen-1,2-dioxy)thiophene] (PEDOT), polypyrole, and polyaniline, but are not limited thereto.

[0083] The hole injection material is a material that receives holes from the anode at a low voltage, and the highest occupied molecular orbital (HOMO) of the hole injection material is preferably between the work function of the anode material and the HOMO of the surrounding organic material layer. Specific examples of the hole injection material include metal porphyrin, oligothiophene, arylamine-based organic material, hexacyno-hexaazatriphenylene-based organic material, quinacridone-based organic material, perylene-based organic material, anthraquinone, and polyaniline-based and polythiophene-based conductive polymers, but are not limited thereto, and can also include another compound capable of p-doping.

[0084] The hole transport material is a material that can receive holes from the anode or the hole injection layer and transport the holes to the light emitting layer, and a material having a high hole mobility is suitable. Specific examples thereof include arylamine-based organic material, conductive polymer, block copolymer having both a conjugated portion and a non-conjugated portion, and the like, but are not limited thereto.

[0085] The light emitting layer can include a host material and a dopant material. Examples of the host material include fused aromatic ring derivatives, heterocycle-containing compounds, and the like. Specifically, examples of the fused aromatic ring derivatives include anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentacene derivatives, phenanthrene compounds, fluoranthene compounds, and the like, and examples of the heterocycle-containing compounds include carbazole derivatives, diphenyl furan derivatives, ladder-type furan compounds, pyrimidine derivatives, and the like, but examples thereof are not limited thereto.

[0086] Examples of the dopant material include aromatic amine derivatives, styryl amine compounds, boron-nitrogen heterocycle-based complexes, fluoranthene compounds, pyrene derivatives, metal complexes, and the like.

[0087] A hole blocking layer can be provided between the electron transport layer and the light-emitting layer, and materials known in the art, such as triazine-based compounds, can be used.

[0088] The electron transport layer can function to facilitate electron transport. An electron transport material is a material that advantageously receives electrons from the cathode and transports the electrons to the light-emitting layer, and a material having a high electron mobility is suitable. The electron transport layer can include an electron buffer layer, a hole blocking layer, an electron transport layer.

[0089] As the cathode material, a material having a small work function is generally preferred to allow smooth injection of electrons into the organic material layer. Specific examples of the cathode material include: a metal such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, and lead, or an alloy thereof; a multi-layered structure material such as LiF / Al or LiO2 / Al; and the like, but are not limited thereto.

[0090] In addition to the light-emitting layer host material disclosed herein including general formula I, existing hole injection materials, hole transport materials, doping materials, hole blocking layers, electron transport layer materials can be used for other layer materials in the OLED device.

[0091] The features and properties of the present application are further described in detail below in connection with examples.

[0092] Example 1

[0093] The present application provides a preparation method of a host material (compound 6), which is prepared by referring to the following synthesis path:

[0094] wherein, the raw material A-6 is prior art (CAS No.: 474688-73-8). The specific process is as follows:

[0095] The raw material A-6 (1.0 eq) (CAS No.: 474688-73-8), the raw material B-6 (1.1 eq) (CAS No.: 2410249-54-4) and potassium carbonate (3.0 eq) were added to a reaction bottle, followed by adding a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and then aerating three times. Tetra (triphenylphosphine) palladium (0.01 eq) was added under nitrogen protection, and the temperature was raised to 95°C and refluxed for 6h. The reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was slightly lowered, and diatomite was used for filtration to remove the salt and catalyst. After the filtrate was cooled to room temperature, it was washed with water three times, and the organic phase was retained. Then the aqueous phase was extracted with dichloromethane. After the organic phases were combined, they were concentrated, and the mixture of dichloromethane and petroleum ether (V:V = 1:5) was used for column chromatography to purify the intermediate 1 (yield: 75.5%).

[0096] Intermediate 1 (1.0 eq), starting material C-6 (1.1 eq) (CAS No: 169126-63-0) and cesium carbonate (3.0 eq) were taken in a reaction flask followed by a mixture of toluene, ethanol, water (V:V:V = 3:1:1), purged with nitrogen three times, palladium acetate (0.05 eq) and X-Phos (0.1 eq) were added under nitrogen atmosphere, the reaction mixture was heated to 95 °C and refluxed for 8 h; the reaction was monitored by TLC, after completion of the reaction, the temperature was lowered, filtered using celite to remove salts and catalyst, the filtrate was cooled to room temperature, washed with water three times, the organic layer was retained, the aqueous layer was extracted with dichloromethane; the organic layers were combined and concentrated, the compound -6 (yield: 77.6%) was purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:6).

[0097] The compound -6 obtained was analyzed and the results are as follows: HPLC purity: >99.8%.

[0098] Mass spectrometry: Mass spectrometer of Waters XEVO TQD type, ESI source. Test value ((ESI, m / Z): [M+H] + ): 657.11.

[0099] Elemental analysis: Calculated: C, 91.43; H, 6.14; O, 2.44; Test value: C, 91.12; H, 6.36; O, 2.68.

[0100] Nuclear magnetic resonance hydrogen spectrum: as shown in Figure 1 (compound 6).

[0101] Example 2

[0102] The present application provides a preparation method of a host material (compound 111), which is prepared by referring to the following synthesis path:

[0103] Specifically as follows: raw material A-111 (1.0 eq) (CAS No: 6134-55-0), raw material B-111 (1.1 eq) (CAS No: 2575133-50-3) and potassium carbonate (3.0 eq) were added to a reaction bottle, followed by adding a mixed solution of toluene, ethanol, water (V:V:V=3:1:1), and then the reaction bottle was ventilated for three times, tetrakis(triphenylphosphine)palladium (0.01 eq) was added under nitrogen protection, the temperature was raised to 95°C, and the reaction was refluxed for 6 h; the reaction was detected by thin layer chromatography, after the reaction was completed, the temperature was slightly lowered, diatomite was used for filtration to remove the salt and catalyst, after the filtrate was cooled to room temperature, it was washed with water for three times, the organic phase was reserved, and then the aqueous phase was extracted with dichloromethane; after the organic phases were combined, they were concentrated, and then the mixture of dichloromethane and petroleum ether (V:V=1:5) was used for column chromatography to purify to obtain intermediate 1 (yield: 75.6%).

[0104] Intermediate 1 (1.0 eq), raw material C-111 (1.1 eq) (CAS No: 100622-34-2) and cesium carbonate (2.0 eq) were added to a reaction bottle, followed by adding a mixed solution of toluene, ethanol, water (V:V:V=3:1:1), and then the reaction bottle was ventilated for three times, palladium acetate (0.05 eq) and X-Phos (0.1 eq) were added under nitrogen protection, the temperature was raised to 95°C, and the reaction was refluxed for 7 h; the reaction was detected by thin layer chromatography, after the reaction was completed, the temperature was slightly lowered, diatomite was used for filtration to remove the salt and catalyst, after the filtrate was cooled to room temperature, it was washed with water for three times, the organic phase was reserved, and then the aqueous phase was extracted with dichloromethane; after the organic phases were combined, they were concentrated, and then the mixture of dichloromethane and petroleum ether (V:V=1:6) was used for column chromatography to purify to obtain intermediate 2 (yield: 71.4%).

[0105] Intermediate 2 (1.0 eq) and raw material D-111 (1.1 eq) (CAS No: 38144-44-4) were added to a reaction bottle, followed by adding dichloromethane, and the reaction was stirred at room temperature for 6 h; the reaction was detected by thin layer chromatography, after the reaction was completed, it was extracted with water for three times, the organic phase was reserved, after the organic phases were combined, they were concentrated, and then the mixture of dichloromethane and petroleum ether (V:V=1:8) was used for column chromatography to purify to obtain intermediate 3 (yield: 80.2%).

[0106] Intermediate 3 (1.0 eq), starting material E-111 (1.1 eq) (CAS No: 2639694-25-8) and potassium carbonate (3.0 eq) were taken in a reaction flask followed by a mixture of toluene, ethanol, water (V:V:V = 3:1:1), purged with nitrogen three times, palladium acetate (0.05 eq) and X-Phos (0.1 eq) were added under nitrogen atmosphere, heated to 95 °C and refluxed for 8 h; the reaction was monitored by thin layer chromatography, after completion of the reaction, the temperature was slightly reduced, filtered using celite to remove salts and catalyst, the filtrate was cooled to room temperature, washed with water thrice, the organic phase was retained and the aqueous phase was extracted with dichloromethane; the organic phases were combined and concentrated, purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:6) to obtain compound-111 (yield: 80.1%).

[0107] Intermediate 4 (1.0 eq), starting material F-111 (1.1 eq) (CAS No: 169126-63-0) and cesium carbonate (3.0 eq) were taken in a reaction flask followed by a mixture of toluene, ethanol, water (V:V:V = 3:1:1), purged with nitrogen three times, palladium acetate (0.05 eq) and X-Phos (0.1 eq) were added under nitrogen atmosphere, heated to 95 °C and refluxed for 8 h; the reaction was monitored by thin layer chromatography, after completion of the reaction, the temperature was slightly reduced, filtered using celite to remove salts and catalyst, the filtrate was cooled to room temperature, washed with water thrice, the organic phase was retained and the aqueous phase was extracted with dichloromethane; the organic phases were combined and concentrated, purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:6) to obtain compound-111 (yield: 80.1%).

[0108] The obtained compound-111 was analyzed and the results were as follows: HPLC purity: >99.7%.

[0109] Mass spectrometry test: test value ((ESI, m / Z): [M+H]+): 843.35.

[0110] Elemental analysis: calculated value: C, 91.17; H, 6.93; O, 1.90; test value: C, 90.89; H, 7.17; O, 2.15.

[0111] Nuclear magnetic resonance hydrogen spectrum: as shown in Figure 2 (Compound 111).

[0112] Example 3

[0113] The present application provides a preparation method of a host material (compound 191), which is prepared by referring to the following synthesis path:

[0114] Specifically as follows: raw material A-191 (1.0 eq) (CAS No: 27452-17-1), raw material B-191 (1.1 eq) (CAS No: 63503-60-6) and potassium carbonate (3.0 eq) were added to a reaction bottle, followed by adding a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and then the gas was exchanged for three times, and then tetrakis(triphenylphosphine)palladium (0.01 eq) was added under nitrogen protection, and the temperature was raised to 95°C and refluxed for 6h; the reaction was detected by thin layer chromatography, after the reaction was completed, the temperature was slightly lowered, and diatomite was used for filtration to remove the salt and catalyst, and then the filtrate was cooled to room temperature, and then washed with water for three times, and then the organic phase was reserved, and then the aqueous phase was extracted with dichloromethane; after the organic phases were combined, they were concentrated, and then the mixture of dichloromethane and petroleum ether (V:V = 1:5) was used for column chromatography to purify to obtain intermediate 1 (yield: 78.7%).

[0115] Intermediate 1 (1.0 eq), raw material C-191 (1.1 eq) (CAS No: 100622-34-2) and cesium carbonate (2.0 eq) were added to a reaction bottle, followed by adding a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and then the gas was exchanged for three times, and then palladium acetate (0.05 eq) and X-Phos (0.1 eq) were added under nitrogen protection, and the temperature was raised to 95°C and refluxed for 7h; the reaction was detected by thin layer chromatography, after the reaction was completed, the temperature was slightly lowered, and diatomite was used for filtration to remove the salt and catalyst, and then the filtrate was cooled to room temperature, and then washed with water for three times, and then the organic phase was reserved, and then the aqueous phase was extracted with dichloromethane; after the organic phases were combined, they were concentrated, and then the mixture of dichloromethane and petroleum ether (V:V = 1:6) was used for column chromatography to purify to obtain intermediate 2 (yield: 80.5%).

[0116] Intermediate 2 (1.0 eq) and raw material D-191 (1.1 eq) (CAS No: 38144-44-4) were added to a reaction bottle, followed by adding dichloromethane, and then the reaction was carried out at room temperature for 6h; the reaction was detected by thin layer chromatography, after the reaction was completed, water was added for extraction for three times, and then the organic phase was reserved, and then the organic phases were combined and concentrated, and then the mixture of dichloromethane and petroleum ether (V:V = 1:8) was used for column chromatography to purify to obtain intermediate 3 (yield: 79.8%).

[0117] Intermediate 3 (1.0 eq), starting material E-191 (1.1 eq) (CAS No: 1627917-17-2) and potassium carbonate (3.0 eq) were taken in a reaction flask followed by a mixture of toluene, ethanol, water (V:V:V = 3:1:1), purged with nitrogen three times, tetrakis(triphenylphosphine)palladium (0.01 eq) was added under nitrogen atmosphere, temperature was raised to 95 °C and the reaction was refluxed for 6 h; the reaction was monitored by thin layer chromatography, after completion of the reaction, temperature was slightly reduced, filtered using celite to remove salts and catalyst, the filtrate was cooled to room temperature, washed with water three times, the organic layer was retained, followed by extraction of the aqueous layer with dichloromethane; the organic layers were combined and concentrated, purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:5) to get compound -191 (yield: 79.5%).

[0118] The compound -191 obtained was analyzed and the results are as follows: HPLC purity: >99.8%.

[0119] Mass spectral test: test value ((ESI, m / Z): [M+H] + ): 657.05.

[0120] Elemental analysis: calculated: C, 91.43; H, 6.14; O, 2.44; test value: C, 91.19; H, 6.31; O, 2.62.

[0121] Nuclear magnetic resonance hydrogen spectrum: as shown in Figure 3 (compound 191).

[0122] Examples 4-52

[0123] The synthesis of the following compounds was completed with reference to the synthesis method of Examples 1 to 3, and the mass spectrometer of Waters XEVO TQD was used for testing, the accuracy was low, and the ESI source was used for testing, and the mass spectral test values are shown in Table 1 below.

[0124] Table 1 Mass spectral test of Examples 4-52

[0125]

[0126]

[0127] In addition, it should be noted that other compounds of the present application can be obtained with reference to the synthesis method of the above-mentioned examples, so hereinafter will not be listed one by one.

[0128] Solubility test:

[0129] The host materials of Examples 1 to 52 and a compound represented by the following structural formula (the compound is prepared by referring to the method of Examples 1 to 3) were respectively put into chlorobenzene, toluene and methyl benzoate, and then the solubility of the compound was recorded, and the results are shown in Table 2.

[0130]

[0131] Table 2 Solubility test

[0132]

[0133]

[0134] From the above table, it can be seen that the solubility of the compound of the present application is much higher than that of the comparative compound in methyl benzoate, toluene and chlorobenzene, especially the solubility in toluene is the most excellent, so toluene is preferred as a solvent to dissolve the compound in the present application in the preparation of devices.

[0135] Device Example 1

[0136] The present application provides a preparation method of an organic electroluminescent device, comprising:

[0137] a, ITO anode: the ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 150 nm is cleaned in distilled water for 2 times, ultrasonic washing for 30 min, and then repeatedly cleaned with distilled water for 2 times, ultrasonic washing for 10 min, after washing, the vacuum oven is baked at 220℃ for 2 hours, and then cooled to be used. The substrate is used as an anode, and other functional layers are prepared on it in sequence.

[0138] b, HIL (hole injection layer): the hole injection layer material HT (compound A) and P-dopant (compound B) are mixed with cyclohexanone at a weight ratio of 8:2 to form a coating composition, which is spin-coated on the prepared transparent ITO electrode to form a hole injection layer with a thickness of 30 nm, and then the coating composition is cured on a hot plate in a nitrogen atmosphere at 220℃ for 30 minutes.

[0139] c, HTL (hole transport layer): the compound A is dissolved in an organic solvent (toluene) at a weight ratio of 1%, and the coating composition is spin-coated on the hole injection layer to form a hole transport layer with a thickness of 40 nm, and then the coating composition is cured on a hot plate in a nitrogen atmosphere at 230℃ for 30 minutes.

[0140] d. EML (Emission Layer): The composition of Compound 1 provided in the above example as a host material and Compound C (concentration of 3%) as a dopant was dissolved in an organic solvent (toluene) at a weight ratio of 0.1%, a hole transport layer was spin-coated to form an emission layer with a thickness of 20 nm, and the coated composition was cured on a hot plate in a nitrogen atmosphere at 120°C for 10 minutes.

[0141] The substrate was then further transferred to an evaporation machine to evaporate other functional layers.

[0142] e. HBL (Hole Blocking Layer): Compound D was evaporated at a rate of 0.1 A / s to form a 5 nm thick HBL on the emission layer.

[0143] f. ETL (Electron Transport Layer): Compound E was evaporated at a rate of 0.1 A / s to form a 20 nm thick ETL on the hole blocking layer.

[0144] g. Cathode: Al was evaporated at a rate of 10 A / s to form a 100 nm thick cathode.

[0145] h. Packaging of the evaporated substrate: First, a coating process was performed using a glue coating device to coat the cleaned cover plate with UV glue, then the coated cover plate was moved to the pressing section, the evaporated substrate was placed on the end of the cover plate, and finally the substrate and cover plate were bonded under the action of the bonding device, and the UV glue was cured by light irradiation.

[0146] The required material structure is shown below:

[0147]

[0148] Device Examples 2-52 and Device Comparative Examples 1-6

[0149] Device Examples 2-52 were prepared according to the preparation method provided in Device Example 1, except that Compound 1 used in Device Example 1 was replaced by Compound 2, 3, 4, 6, 7, 22, 28, 34, 43, 45, 47, 50, 51, 52, 63, 72, 81, 89, 95, 100, 111, 112, 113, 124, 148, 149, 160, 164, 169, 184, 185, 191, 193, 205, 213, 214, 223, 232, 235, 240, 244, 266, 274, 286, 289, 290, 302, 307, 312, 316, 328, respectively, as the emission layer host material, to prepare the corresponding organic electroluminescent devices.

[0150] ​​The organic electroluminescent devices were prepared according to the preparation method provided in Device Example 1, except that the compound 1 used in Device Example 1 was replaced by the above-mentioned compounds a, b, c, d, e and f, respectively.

[0151] The driving voltage, luminous efficiency, lifetime and the like of the organic electroluminescent devices obtained from Device Examples 1 to 52 and Device Comparative Examples 1 to 6 above were characterized at a brightness of 1000 (nits), and the test results are as follows in Table 3:

[0152] Table 3 Test results of organic electroluminescent devices

[0153]

[0154]

[0155] Wherein, the luminous efficiency here is the current efficiency, which refers to the ratio of the luminous brightness of the device to the current density, and the unit is candela per ampere (cd / A); the lifetime is defined as the time (T95) required for the brightness of the device to reduce to 95% of the initial brightness under constant voltage or constant current conditions.

[0156] According to Table 3 above, the light-emitting wavelength of the device made of the compound in the application is about 460 nm. Moreover, the organic electroluminescent device prepared by using the compound provided in the application as the host material in the light-emitting layer has more excellent solubility than the organic electroluminescent device prepared by using the comparative compounds a to f (Device Comparative Examples 1 to 6) as the host material, is more conducive to the preparation of the device by the solvent method, and the efficiency and the lifetime of the device are greatly improved.

[0157] Comparative compound a and compound 191 are parallel comparative examples, the difference between which is that comparative compound a is connected with a tetramethyl-tetrahydro-naphthobenzofuran group at the same position as the anthracene group, and comparative compound has two rigid and sterically hindered groups (benzonaphthofuran and tetramethyl-tetrahydro-naphthobenzofuran) at the same time, which makes the configuration twist too large and is easy to form carrier traps. However, in compound 191 in the application, the tetramethyl-tetrahydro group naphthalene is connected with the anthracene group by a meta-phenylene group. On the one hand, the conjugation length of the host material is extended by the buffering of the phenylene group, which is conducive to the formation of long-range structure and is more conducive to the injection and transport of carriers, thereby improving the luminous efficiency of the device. On the other hand, the meta-connection mode increases the dihedral angle of the anthracene group and the tetramethyl-tetrahydro naphthalene group, increases the molecular volume, reduces the aggregation and accumulation of molecules, and improves the solubility of the compound, which is more conducive to the operation of the device in the later stage.

[0158] The comparative compound b and the compounds 4 and 6 are parallel comparative examples, which are different in that the compound 4 in the application is connected with a phenyl on one side of the anthracene group, the compound 6 is connected with a naphthyl on one side of the anthracene group, and the comparative compound b is connected with a dibenzo-p-dioxin group on one side of the anthracene group, which increases the molecular weight of the compound, makes the configuration torsion angle larger, reduces the intermolecular distance, is not conducive to the operation of the device made of the material in the later stage, and the electrical stability of the group is poor, which affects the test effect of the material in the later stage.

[0159] The comparative compounds c and d and the compounds 184 and 185 are parallel comparative examples, respectively, which are different in that the comparative compounds c and d are the prior research of the inventor recorded in CN113149943A, which is connected with a single phenyl at the corresponding position. Since the solubility of the compounds c and d in toluene is low, the material itself agglomerates, the doped material cannot be better doped into the host material, which reduces the energy transfer efficiency and reduces the efficiency and the life. In the application, a tetramethyltetrahydronaphthyl group is connected to the benzonaphthofuran in the compounds 184 and 185 as a substituent, which increases the rigid structure of the compound and enhances the stability, and at the same time, it increases the molecular volume, effectively improves the solubility of the material, and the device prepared by taking the compound as a blue fluorescent host material has better luminous efficiency and longer life.

[0160] The comparative compounds e and f and the compounds 95 and 266 and the compounds 7 and 164 are parallel comparative examples, respectively, which are different in that the tetramethyltetrahydronaphthyl group in the comparative compound e is directly connected with the anthracene group, and the tetramethyltetrahydronaphthyl group in the comparative compound f is first connected with the phenyl, and then connected with the anthracene group at the para position. The para connection reduces the solubility of the compound, while in the application, the tetramethyltetrahydronaphthyl group on one side of the compounds 95 and 266 and the compounds 7 and 164 is first connected with the diphenylfuran and the benzonaphthofuran, respectively, and then connected with the anthracene group. The advantage is that the diphenylfuran group has a weak electron-withdrawing effect, which can improve the electron transport property of the material, promote the improvement of the device efficiency, and at the same time, increase the conjugation, improve the receiving and transmission ability of the material to electrons. In addition, it presents a rigid planar configuration, improves the stability of the compound, and further improves the life of the device.

[0161] The above only describes the preferred embodiments of the application and is not intended to limit the application. Those skilled in the art can make various modifications and changes to the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A host material characterized in that, Any one of the compounds shown in the following structural formulae: 。 2. A light emitting layer material, characterized in that, The host material is as claimed in claim 1.

3. An organic electroluminescent device, characterized by comprising The organic layer is prepared by the light-emitting layer material as claimed in claim 2.

4. The organic electroluminescent device according to claim 3, characterized in that The organic layer comprises at least one of a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer and an electron injection layer, and the light-emitting layer is prepared by the light-emitting layer material as claimed in claim 2.

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