Host material containing sulfur or selenium heavy atoms and electroluminescent application thereof

Abstract

The invention discloses a sulfur or selenium heavy atom-containing host material and electroluminescent application thereof, and belongs to the technical field of organic electroluminescence. The host material has a structure as shown in a general formula (1), wherein R1 and R2 in the general formula (1) represent electron-rich groups with hole transport capability or electron-deficient groups with electron transport capability. The main body material can form exciplex action with TADF dye, can effectively promote trans-intersystem crossing of the TADF dye, and can be used for preparing electroluminescent devices. The main body material is used as a main body of a TADF dye to prepare an electroluminescent device, and the device has excellent performances of high efficiency, low efficiency roll-off and the like. General formula (1)

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescence technology, specifically relating to a host material containing sulfur or selenium heavy atoms and its electroluminescence application. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are electrically driven light-emitting devices that use organic materials as functional materials. Specifically, they refer to the technology where organic semiconductor materials and organic light-emitting materials emit light through carrier injection and recombination under the drive of an electric field. Compared with inorganic materials, organic materials have advantages such as ease of preparation, easily tunable properties, flexibility, and good film formation. OLEDs based on organic materials typically have simple fabrication processes, are easy to fabricate in large areas, are environmentally friendly, and can be fabricated using low-temperature thin-film methods, resulting in low manufacturing costs. Compared with liquid crystal display technology, organic OLEDs offer a series of advantages such as self-illumination, low-voltage DC drive, full curing, wide viewing angle, and rich colors, demonstrating broad application prospects and being considered one of the most competitive flat panel display technologies.

[0003] A typical example of an organic light-emitting diode (OLED) is the organic light-emitting diode. OLEDs generally employ a sandwich structure: a transparent conductive anode, a hole injection layer, a hole transport layer, an exciton-electron blocking layer, an emissive layer, an exciton-hole blocking layer, an electron transport layer, an electron injection layer, and a metal cathode. The emissive layer consists of a host material and a luminescent dye doped within the host. The luminescent dye directly determines the device's performance. In the emissive layer, holes and electrons recombine to generate 25% singlet excitons and 75% triplet excitons. Fluorescent materials were initially used in OLED devices. However, because traditional fluorescent materials can only emit light using singlet excitons, the internal quantum efficiency of fluorescent devices is generally less than 25%. Subsequently, metal complex phosphorescent materials were widely used in OLEDs. Because phosphorescent materials can emit phosphorescence using both singlet and triplet excitons simultaneously, the internal quantum efficiency of phosphorescent devices can reach up to 100%. However, phosphorescent materials often use precious metals such as iridium and platinum, resulting in high material costs. Professor Adachi and colleagues in Japan proposed using thermally-activated delayed fluorescence (TADF) materials to fabricate OLED devices. TADF materials are generally pure organic molecules, thus offering low material costs. TADF materials possess extremely small energy differences between singlet and triplet states. Under ambient thermal excitation, triplet excitons can cross back to the singlet state via antisystem crossing, thereby emitting delayed fluorescence. Therefore, OLEDs fabricated using TADF materials can achieve a maximum internal quantum efficiency of 100%. Due to its significant advantages such as high efficiency and low material cost, TADF materials have become the third generation of organic electroluminescent materials after fluorescent and phosphorescent materials.

[0004] The anti-intersystem crossing rate of TADF materials directly determines the performance of corresponding OLED devices. When the anti-intersystem crossing rate is low, OLED devices exhibit severe efficiency roll-off (i.e., device efficiency decreases rapidly at high brightness). Therefore, improving the anti-intersystem crossing rate of TADF materials is crucial. Traditional methods to improve the anti-intersystem crossing rate of TADF materials include reducing the singlet-triplet energy level difference or increasing spin-orbit coupling. These methods generally require complex molecular design and synthesis. Therefore, finding a simple and effective way to improve the anti-intersystem crossing rate of TADF materials and suppress the efficiency roll-off of OLED devices is a challenge in the research of these materials and devices. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and provide a host material containing heavy atoms that can form excitocomplexes with TADF dyes and effectively promote the inter-system crossing of TADF dyes.

[0006] Another object of the present invention is to provide the application of the aforementioned host material in the fabrication of high-performance electroluminescent devices. These devices exhibit superior properties such as high efficiency and low efficiency roll-off.

[0007] The objective of this invention is achieved through the following technical solution: A host material containing heavy atoms that can form excitosome complexes with TADF dyes and effectively promote inter-tandem crossing of TADF dyes has the following general formula (1):

[0008] General formula (1) Furthermore, the general formula (1) includes the following general formulas (2)-(13):

[0009] Wherein, R1 and R2 represent electron-rich groups with hole transport capability or electron-deficient groups with electron transport capability, and R1 and R2 are each independently selected from: arylamine, alkyl, alkoxy or aryl-substituted arylamine, carbazolyl, alkyl, alkoxy, aryl or aryl-substituted carbazolyl, 9,10-dihydroacridinyl, phenoxazinyl, alkyl, alkoxy or aryl-substituted phenoxazinyl, phenthiazinyl, alkyl, alkoxy or aryl-substituted phenthiazinyl, pyridinyl, aryl-substituted pyridinyl, pyrimidinyl, aryl-substituted pyrimidinyl, triazinyl, aryl-substituted triazinyl, benzophenone, aryl-substituted benzophenone, xanthonone, aryl-substituted xanthonone, spirofluorenyl, aryl-substituted spirofluorenyl, etc. The aromatic amino group is preferably a C12-C52 aromatic amino group, the alkyl group is preferably a C1-C4 alkyl group, the alkoxy group is preferably a C1-C4 alkoxy group, and the aryl group is preferably a C6-C52 aryl group.

[0010] Furthermore, R1 and R2 are each preferably selected independently from the following groups:

[0011] Among them, R3 R 30 Each group is independently selected from: hydrogen, alkyl, cycloalkyl, alkoxy, aryl, alkyl, cycloalkyl, or alkoxy-substituted aryl, alkyl, cycloalkyl, or alkoxy-substituted heteroaryl, and alkyl, cycloalkyl, or alkoxy-substituted heterocyclic groups. The alkyl group is preferably an alkyl group with five or fewer carbon atoms, the cycloalkyl group is preferably a cycloalkyl group with six or fewer members, the alkoxy group is preferably an alkoxy group with five or fewer carbon atoms, the aryl group is preferably a C6-C52 aryl group, and the heteroaryl or heterocyclic group is preferably a five- or six-membered ring heteroaryl or heterocyclic group.

[0012] Furthermore, the substituents R1 and R2 in general formulas (2)-(13) are each preferably selected independently from the following groups, which can be combined in any pair to obtain the corresponding host material:

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021] Furthermore, the main material is preferably selected from compounds with the structures shown in (1)-(120) below:

[0022]

[0023]

[0024] The above-mentioned host material is used in the fabrication of electroluminescent devices. The host material can be used as a material for hole injection, hole transport, light emission, electron transport, electron blocking, or electron injection.

[0025] In a preferred embodiment, the host material is doped with TADF dye as a luminescent dye and used to prepare the luminescent functional layer of an electroluminescent device.

[0026] In a preferred embodiment, the electroluminescent device includes an anode, a cathode, and a hole injection layer, a hole transport layer, an exciton / electron blocking layer, a light-emitting functional layer, an electron transport layer, and an electron injection layer located between the two electrodes, wherein the light-emitting functional layer contains the host material described in this invention. However, the structure of the electroluminescent device is not limited to this and may include more or fewer organic functional layers.

[0027] TADF materials typically exhibit low anti-system crossing rates, easily leading to severe efficiency roll-off in OLED devices at high brightness. Traditional methods to improve the anti-system crossing rate of TADF materials generally involve chemical modifications, which suffer from complex molecular design and synthesis, and can negatively impact other luminescent properties (such as causing redshift or spectral broadening). This invention utilizes structural units containing S and Se heavy atoms, and introduces suitable electron-rich groups with hole transport capabilities or electron-deficient groups with electron transport capabilities onto these units to obtain a host material. This host material can form excitocomplexes with corresponding TADF dyes. The triplet state of the resulting excitocomplex can act as an intermediate state to promote anti-system crossing in TADF materials. Furthermore, the heavy atoms in the host material further enhance the spin-orbit coupling between the triplet state of the excitocomplex and the singlet state of the TADF dye, thereby significantly accelerating the anti-system crossing of the TADF dye. Therefore, the resulting host material has the advantage of significantly promoting anti-system crossing in TADF dyes. Using this type of host material as the host for TADF dyes in organic electroluminescent devices results in devices with high luminous efficiency and minimal efficiency roll-off.

[0028] The key to the host material in this invention lies in the use of structural units containing S and Se heavy atoms, and the introduction of suitable hole or electron transport groups. By utilizing the excitocomplex interaction between the host material and the corresponding TADF dye, as well as the heavy atom effect of the host material, the anti-intersystem crossing of the TADF dye is significantly promoted, thereby suppressing the efficiency roll-off of OLED devices. In OLED devices, TADF dyes utilize anti-intersystem crossing to convert non-luminescent triplet excitons into luminescent singlet excitons, achieving 100% exciton utilization. The speed of anti-intersystem crossing directly determines the utilization efficiency of triplet excitons and the device efficiency. Slow anti-intersystem crossing not only reduces device efficiency but also causes the accumulation of triplet excitons in the emitting layer, leading to a severe efficiency roll-off at high brightness (i.e., a significant decrease in device efficiency at high brightness). Currently reported methods for improving the anti-intersystem crossing rate of TADF dyes generally involve chemically modifying the TADF dye, which suffers from serious problems such as complex molecular design and synthesis, and the potential to affect other luminescent properties of the dye (e.g., causing a redshift or spectral broadening of the dye's emission). In the technical solution of this invention, structural units containing S and Se heavy atoms are used, and suitable hole or electron transport groups are introduced to obtain a host material containing heavy atoms with suitable energy levels and excellent hole / electron transport capabilities. This host material can form an excitocomplex with TADF dyes of matching energy levels. The triplet state of this excitocomplex can act as an intermediate state to promote anti-system crossing of the TADF dye. More importantly, the heavy atoms in the host material can further enhance the spin-orbit coupling between the triplet state of the excitocomplex and the singlet state of the TADF dye, thereby significantly promoting anti-system crossing of the TADF dye. When the host material of this invention is used as the host for TADF dyes to prepare electroluminescent devices, the devices exhibit superior performance such as high efficiency and low efficiency roll-off.

[0029] Compared with the prior art, the technical solution of the present invention has the following advantages: (1) The main material of the present invention uses structural units containing heavy S and Se atoms and introduces suitable hole or electron transport groups; by utilizing the interaction of the main material with the excitocomplex of the corresponding TADF dye and the heavy atom effect of the main material, the anti-system crossing of TADF dye can be significantly promoted.

[0030] (2) The present invention uses this type of host material as the host of TADF dye to prepare electroluminescent devices, which have superior performance such as high efficiency and low efficiency roll-off. At the same time, the light-emitting layer of the device adopts a binary structure (host + dye), which simplifies the device preparation.

[0031] (3) The main material of the present invention is synthesized using a mature process, which is easy to prepare and greatly reduces the cost of using the material. Hole or electron transport groups are easy to adjust, and the energy level and transport properties of the main material can be easily controlled. Attached Figure Description

[0032] Figure 1 It is compound 11 1 H NMR spectroscopy.

[0033] Figure 2 It is compound 19. 1 H NMR spectroscopy.

[0034] Figure 3 It is compound 99. 1 H NMR spectroscopy.

[0035] Figure 4 This is the single-crystal structure diagram of compound 19.

[0036] Figure 5 This is a schematic diagram of the light-emitting device structure in the application examples (Examples 2-4).

[0037] Figure 6 These are the current density-voltage-brightness diagrams for devices 2-8, 3-6, and 4-2.

[0038] Figure 7 These are the external quantum efficiency-luminosity diagrams for devices 2-8, 3-6, and 4-2. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0040] Example 1: Synthesis of the compound The compounds of general formula (1) and its subordinate general formulas (2)-(13) of this invention are prepared by the following reaction scheme: Reaction formula (1):

[0041] Reaction (2):

[0042] Reaction (3):

[0043] Reaction formula (4):

[0044] The reaction formula involves instances in which specific substituents are introduced; however, if necessary, those skilled in the art can introduce substituents using techniques known in the art, and the type or number of substituents can be varied during introduction. Furthermore, those skilled in the art can modify the sample, reaction conditions, or starting materials of the above reaction formula using techniques known in the art. For example, a compound represented by general formula (1) can be prepared according to the above reaction formula (1), and substituents can be bonded to it using methods known in the art; the type, position, or number of substituents can be varied according to techniques known in the art. However, the reaction is not limited thereto.

[0045] For example, the compound represented by general formula (2) can be synthesized according to the following reaction:

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055] (1) Synthesis of Compound 1: 2,8-dibromodibenzothiophene (4.12 g, 12 mmol), 3,6-dimethoxycarbazole (2.72 g, 12 mmol), sodium tert-butoxide (3.46 g, 36 mmol), toluene (50 mL), tris(dibenzylacetone)dipalladium (550 mg, 0.60 mmol), and tri-tert-butylphosphine tetrafluoroborate (696 mg, 2.40 mmol) were added sequentially to a round-bottom flask. The mixture was heated to 100 °C and refluxed under nitrogen. The reaction was monitored by TLC until complete. The reaction solution was cooled to room temperature and evaporated to dryness. The solvent was evaporated and the mixture was stirred. The solution was separated by silica gel column chromatography and dried to obtain intermediate A1-1 as a white solid product of 5.00 g, with a yield of 85%.

[0056] Intermediate A1-1 (1.12 g, 2.3 mmol), 9,9-spirodifluorene-3-borate pinacol ester (1.53 g, 3.5 mmol), potassium carbonate (1.27 g, 9.2 mmol), tetrakis(triphenylphosphine)palladium (133 mg, 0.12 mmol), toluene (15 mL), ethanol (15 mL), and water (5 mL) were added to a 100 mL round-bottom flask. The mixture was heated to 70 °C and refluxed under nitrogen. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, it was evaporated to dryness. The organic phase was extracted with dichloromethane and washed with water. The organic phase was dried with anhydrous sodium sulfate, and the solvent was evaporated to dryness. The mixture was then stirred. The product was separated by silica gel column chromatography and dried to obtain compound 1 as a white solid powder, yielding 1.13 g of the product (68%).

[0057] (2) Synthesis of Compound 2: Intermediate A1-1 (1.26 g, 2.3 mmol), 3,9'-bicarbazole (1.15 g, 3.5 mmol), potassium carbonate (1.27 g, 9.2 mmol), tetraphenylphosphine palladium (133 mg, 0.12 mmol), toluene (15 mL), ethanol (15 mL), and water (5 mL) were added to a 100 mL round-bottom flask. The mixture was heated to 70 °C and refluxed under nitrogen. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, it was evaporated to dryness. The organic phase was extracted with dichloromethane and washed with water. The organic phase was dried with anhydrous sodium sulfate, the solvent was evaporated, and the sample was mixed. The mixture was separated by silica gel column chromatography and dried to obtain 1.20 g of compound 2 as a white solid powder, with a yield of 70%.

[0058] (3) Synthesis of Compound 3: 2,8-dibromodibenzothiophene (1.03 g, 3 mmol), 3,9'-bicarbazole (2.49 g, 7.5 mmol), sodium tert-butoxide (1.73 g, 18 mmol), toluene (30 mL), tris(dibenzylacetone)dipalladium (550 mg, 0.60 mmol), and tri-tert-butylphosphine tetrafluoroborate (348 mg, 1.20 mmol) were heated to 100 °C and refluxed under nitrogen. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, it was evaporated to dryness. The organic phase was extracted with dichloromethane and washed with water. The organic phase was dried with anhydrous sodium sulfate, the solvent was evaporated, and the sample was mixed. The mixture was separated by silica gel column chromatography and dried to obtain 1.29 g of compound 3 as a white solid powder, with a yield of 62%.

[0059] (4) Synthesis of compound 4: 2,8-dibromodibenzothiophene (2.06 g, 6 mmol), 3,9'-bicarbazole (2.00 g, 6 mmol), sodium tert-butoxide (1.73 g, 18 mmol), toluene (30 mL), tris(dibenzylacetone)dipalladium (275 mg, 0.30 mmol), and tri-tert-butylphosphine tetrafluoroborate (348 mg, 1.20 mmol) were added to a 100 mL round-bottom flask, heated to 100 °C, and refluxed under nitrogen. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, it was evaporated to dryness and mixed. Separation was performed by silica gel column chromatography, and the product was dried to obtain intermediate A1-2 as a white solid powder, with a yield of 2.85 g and a yield of 81%.

[0060] Intermediate A1-2 (1.42 g, 2.4 mmol), 9,9-spirodifluorene-3-borate pinacol ester (1.59 g, 3.6 mmol), potassium carbonate (1.27 g, 9.2 mmol), tetrakis(triphenylphosphine)palladium (133 mg, 0.12 mmol), toluene (15 mL), ethanol (15 mL), and water (5 mL) were added to a 100 mL round-bottom flask. The mixture was heated to 70 °C and refluxed under nitrogen. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, it was evaporated to dryness. The organic phase was extracted with dichloromethane and washed with water. The organic phase was dried with anhydrous sodium sulfate, and the solvent was evaporated to dryness. The mixture was then stirred. The product was separated by silica gel column chromatography and dried to obtain compound 4 as a white solid powder, yielding 1.51 g of the product (76%).

[0061] (5) Synthesis of compound 5: 2,8-dibromodibenzothiophene (2.06 g, 6 mmol), 3,6-(dicarbazolyl)tricarbazolium (3.00 g, 6 mmol), sodium tert-butoxide (1.73 g, 18 mmol), toluene (30 mL), tris(dibenzylacetone)dipalladium (275 mg, 0.30 mmol), and tri-tert-butylphosphine tetrafluoroborate (348 mg, 1.20 mmol) were added to a 100 mL round-bottom flask, heated to 100 °C, and refluxed under nitrogen. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, it was evaporated to dryness and mixed. Separation was performed by silica gel column chromatography, and the product was dried to obtain intermediate A1-3 as a white solid powder, yielding 3.55 g, with a yield of 78%.

[0062] Intermediate A1-3 (1.82 g, 2.4 mmol), pinacol 9,9-spirodifluorene-3-borate (1.59 g, 3.6 mmol), potassium carbonate (1.27 g, 9.2 mmol), tetraphenylphosphine palladium (133 mg, 0.12 mmol), toluene (15 mL), ethanol (15 mL), and water (5 mL) were added to a 100 mL round-bottom flask. The mixture was heated to 70 °C and refluxed under nitrogen. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, it was evaporated to dryness. The organic phase was extracted with dichloromethane and washed with water. The organic phase was dried with anhydrous sodium sulfate, and the solvent was evaporated to dryness. The mixture was then stirred. The product was separated by silica gel column chromatography and dried to obtain compound 5 as a white solid powder, yielding 1.84 g of the product (77%).

[0063] (6) Synthesis of Compound 6: Dibenzothiophene-2-boronic acid (1.03 g, 4.5 mmol), 9-(3-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)phenyl)-9H-carbazole (1.30 g, 3 mmol), potassium carbonate (1.66 g, 12 mmol), tetrakis(triphenylphosphine)palladium (173 mg, 0.15 mmol), toluene (15 mL), ethanol (15 mL), and water (5 mL) were added to a 100 mL round-bottom flask. The mixture was heated to 70 °C and refluxed under nitrogen. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, it was evaporated to dryness. The organic phase was extracted with dichloromethane and washed with water. The organic phase was dried with anhydrous sodium sulfate, the solvent was evaporated, and the sample was mixed. The mixture was separated by silica gel column chromatography and dried to obtain 1.08 g of compound 6 as a white solid powder, with a yield of 62%.

[0064] (7) Synthesis of compound 7: Dibenzothiophene-2-boronic acid (1.03 g, 4.5 mmol), 5-(3-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)phenyl)-7,7-dimethyl-5,7-dihydroindo[2,1-b]carbazole (1.65 g, 3 mmol), potassium carbonate (1.66 g, 12 mmol), tetrakis(triphenylphosphine)palladium (173 mg, 0.15 mmol), toluene (15 mL), ethanol (15 mL), and water (5 mL) were added to a 100 mL round-bottom flask. The mixture was heated to 70 °C and refluxed under nitrogen. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, it was evaporated to dryness. The organic phase was extracted with dichloromethane and washed with water. It was dried with anhydrous sodium sulfate, the solvent was evaporated to dryness, and the sample was mixed. The compound 7 was separated by silica gel column chromatography and dried to obtain 1.28 g of white solid powder product, with a yield of 61%.

[0065] (8) Synthesis of Compound 8: Intermediate A1-1 (1.12 g, 2.3 mmol), pinacol diborate (876 mg, 3.5 mmol), potassium acetate (902 mg, 9.2 mmol), 1,1-bis(diphenylphosphine)diberberine palladium dichloride (84 mg, 0.1 mmol), and 1,4-dioxane (20 mL) were added sequentially to a round-bottom flask. The mixture was heated to 100 °C and refluxed under nitrogen protection. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, the mixture was stirred, separated by silica gel column chromatography, and dried to obtain intermediate B-1 as a white solid powder product of 948 mg, with a yield of 77%.

[0066] Intermediate B-1 (948 mg, 1.8 mmol), 2-chloro-4,6-diphenyl-1,3,5-triazine (723 mg, 2.7 mmol), potassium carbonate (995 mg, 7.2 mmol), tetraphenylphosphine palladium (104 mg, 0.09 mmol), toluene (6 mL), ethanol (6 mL), and water (2 mL) were added to a 100 mL round-bottom flask. The mixture was heated to 70 °C and refluxed under nitrogen. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, it was evaporated to dryness. The organic phase was extracted with dichloromethane and washed with water. The organic phase was dried with anhydrous sodium sulfate, and the solvent was evaporated to dryness. The mixture was then stirred. The product was separated by silica gel column chromatography and dried to obtain compound 8 as a white solid powder, 727 mg in yield (63%).

[0067] (9) Synthesis of Compound 9: Dibenzothiophene-2-boronic acid (1.03 g, 4.5 mmol), 2-(9,9'-spiro[fluorene]-3-yl)-4-chloro-6-phenyl-1,3,5-triazine (1.52 g, 3 mmol), potassium carbonate (1.66 g, 12 mmol), tetrakis(triphenylphosphine)palladium (173 mg, 0.15 mmol), toluene (15 mL), ethanol (15 mL), and water (5 mL) were added to a 100 mL round-bottom flask. The mixture was heated to 70 °C and refluxed under nitrogen. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, it was evaporated to dryness. The organic phase was extracted with dichloromethane and washed with water. The organic phase was dried with anhydrous sodium sulfate, the solvent was evaporated, and the sample was mixed. The mixture was separated by silica gel column chromatography and dried to obtain 1.26 g of compound 9 as a white solid powder, with a yield of 64%.

[0068] (10) Synthesis of Compound 10: Dibenzothiophene-3-boronic acid (1.71 g, 7.5 mmol), 2-(9,9'-spiro[fluorene]-3-yl)-4-chloro-6-phenyl-1,3,5-triazine (1.52 g, 3 mmol), potassium carbonate (1.66 g, 12 mmol), tetrakis(triphenylphosphine)palladium (173 mg, 0.15 mmol), toluene (15 mL), ethanol (15 mL), and water (5 mL) were added to a 100 mL round-bottom flask. The mixture was heated to 70 °C and refluxed under nitrogen. The reaction was monitored by TLC until complete. After the reaction solution cooled to room temperature, it was evaporated to dryness. The organic phase was extracted with dichloromethane and washed with water. The organic phase was dried with anhydrous sodium sulfate, the solvent was evaporated, and the sample was mixed. The mixture was separated by silica gel column chromatography and dried to obtain 1.32 g of compound 10 as a white solid powder, with a yield of 58%.

[0069] Compounds of general formulas (3)-(13) can be synthesized by following the above methods, for example: (11) Synthesis of compound 11: Compound 11 was synthesized in the same manner as compound 1. The synthesis of intermediate A2-1 was similar to that of intermediate A1-1. The only difference was that the starting material 2,8-dibromodibenzothiophene was replaced with 2-bromo-7-chlorodibenzoselenophene.

[0070] (12) Synthesis of compound 12: Compound 12 was synthesized in the same manner as compound 2. The synthesis of intermediate A2-1 was similar to that of intermediate A2-1. The only difference was that the starting material 2,8-dibromodibenzothiophene was replaced with 2-bromo-7-chlorodibenzoselenide.

[0071] (13) Synthesis of compound 13: Compound 13 was synthesized in the same manner as compound 3. The only difference was that the starting material 2,8-dibromodibenzothiophene was replaced with 2-bromo-7-chlorodibenzoselenene.

[0072] (14) Synthesis of compound 14: Compound 14 was synthesized in the same manner as compound 4. The synthesis of intermediate A2-2 was similar to that of intermediate A1-2. The only difference was that the starting material 2,8-dibromodibenzothiophene was replaced with 2-bromo-7-chlorodibenzoselenide.

[0073] (15) Synthesis of compound 15: Compound 15 was synthesized in the same manner as compound 5. The synthesis of intermediate A2-3 was similar to that of intermediate A1-3, except that the starting material 2,8-dibromodibenzothiophene was replaced with 2-bromo-7-chlorodibenzoselenene.

[0074] (16) Synthesis of compound 16: Compound 16 was synthesized in the same manner as compound 6, except that the raw material dibenzothiophene-2-boronic acid was replaced with dibenzoselenophene-2-boronic acid pinacol ester.

[0075] (17) Synthesis of compound 17: Compound 17 was synthesized in the same manner as compound 7. The only difference was that the raw material dibenzothiophene-2-boronic acid was replaced with dibenzoselenophene-3-boronic acid pinacol ester.

[0076] (18) Synthesis of compound 18: Compound 18 was synthesized in the same manner as compound 8. The synthesis of intermediate B-2 was similar to that of intermediate B-1. The only difference was that the starting material 2,8-dibromodibenzothiophene was replaced with 2-bromo-7-chlorodibenzoselenide.

[0077] (19) Synthesis of compound 19: Compound 19 was synthesized in the same manner as compound 9. The only difference was that the raw material dibenzothiophene-2-boronic acid was replaced with dibenzoselenophene-3-boronic acid pinacol ester.

[0078] (20) Synthesis of compound 20: Compound 20 was synthesized in the same manner as compound 10, except that the raw material dibenzothiophene-3-boronic acid was replaced with dibenzoselenophene-2-boronic acid pinacol ester.

[0079] Synthesis of Compounds 21-30: Compounds 21-30 were synthesized similarly to Compounds 1-10, except that: 2,8-dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]thiophene (Compound 21); 2,8-dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]thiophene (Compound 22); 2,8-dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]thiophene (Compound 23); 2,8-dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]thiophene (Compound 24); 2,8-dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]thiophene. 8-Dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]thiophene (compound 25); the raw material dibenzothiophene-2-boric acid was replaced with benzo[b]thiophene-3-boric acid (compound 26); the raw material dibenzothiophene-2-boric acid was replaced with benzo[b]thiophene-6-boric acid (compound 27); the raw material 2,8-dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]thiophene (compound 28); the raw material dibenzothiophene-2-boric acid was replaced with benzo[b]thiophene-6-boric acid (compound 29); the raw material dibenzothiophene-3-boric acid was replaced with benzo[b]thiophene-3-boric acid (compound 30).

[0080] Synthesis of Compounds 31-40: Compounds 31-40 were synthesized similarly to Compounds 1-10, except that the following steps were taken: 2,8-dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]selenophene (Compound 31); 2,8-dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]selenophene (Compound 32); 2,8-dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]selenophene (Compound 33); 2,8-dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]selenophene (Compound 34); 2,8-dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]selenophene. 8-Dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]selenophene (compound 35); the raw material dibenzothiophene-2-boric acid was replaced with benzo[b]selenophene-3-boric acid (compound 36); the raw material dibenzothiophene-2-boric acid was replaced with benzo[b]selenophene-6-boric acid (compound 37); the raw material 2,8-dibromodibenzothiophene was replaced with 3-bromo-6-chlorobenzo[b]selenophene (compound 38); the raw material dibenzothiophene-2-boric acid was replaced with benzo[b]selenophene-6-boric acid (compound 39); the raw material dibenzothiophene-3-boric acid was replaced with benzo[b]selenophene-3-boric acid (compound 40).

[0081] Synthesis of Compounds 41-50: Compounds 41-50 were synthesized similarly to Compounds 1-10, except that the following steps were taken: 2,8-dibromodibenzothiophene was replaced with 2,7-dibromo-phenoxathiophene (Compound 41); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromo-phenoxathiophene (Compound 42); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromo-phenoxathiophene (Compound 43); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromo-phenoxathiophene (Compound 44); ,8-Dibromodibenzothiophene was replaced with 2,7-dibromo-phenoxthiophene (compound 45); the raw material dibenzothiophene-2-boric acid was replaced with phenoxthiophene-2-boric acid (compound 46); the raw material dibenzothiophene-2-boric acid was replaced with phenoxthiophene-2-boric acid (compound 47); the raw material 2,8-dibromodibenzothiophene was replaced with 2,7-dibromo-phenoxthiophene (compound 48); the raw material dibenzothiophene-2-boric acid was replaced with phenoxthiophene-3-boric acid (compound 49); the raw material dibenzothiophene-3-boric acid was replaced with phenoxthiophene-2-boric acid (compound 50).

[0082] Synthesis of Compounds 51-60: Compounds 51-60 were synthesized similarly to Compounds 1-10, except that the following steps were taken: 2,8-dibromodibenzothiophene was replaced with 2,7-dibromo-selenoxthiophene (Compound 51); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromo-selenoxthiophene (Compound 52); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromo-selenoxthiophene (Compound 53); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromo-selenoxthiophene (Compound 54); ,8-Dibromodibenzothiophene was replaced with 2,7-dibromo-selenoxthiophene (compound 55); the raw material dibenzothiophene-2-boric acid was replaced with selenoxthiophene-2-boric acid (compound 56); the raw material dibenzothiophene-2-boric acid was replaced with selenoxthiophene-3-boric acid (compound 57); the raw material 2,8-dibromodibenzothiophene was replaced with 2,7-dibromo-selenoxthiophene (compound 58); the raw material dibenzothiophene-2-boric acid was replaced with phenoxthiophene-3-boric acid (compound 59); the raw material dibenzothiophene-3-boric acid was replaced with selenoxthiophene-2-boric acid (compound 60).

[0083] Synthesis of Compounds 61-70: Compounds 61-70 were synthesized similarly to Compounds 1-10, except that the following steps were taken: 2,8-dibromodibenzothiophene was replaced with 2,7-dibromothiathracene (Compound 61); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromothiathracene (Compound 62); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromothiathracene (Compound 63); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromothiathracene (Compound 64); ,8-Dibromodibenzothiophene was replaced with 2,7-dibromothianthracene (compound 65); the raw material dibenzothiophene-2-boric acid was replaced with thianthracene-2-boric acid (compound 66); the raw material dibenzothiophene-2-boric acid was replaced with thianthracene-2-boric acid (compound 67); the raw material 2,8-dibromodibenzothiophene was replaced with 2,7-dibromothianthracene (compound 68); the raw material dibenzothiophene-2-boric acid was replaced with thianthracene-2-boric acid (compound 69); the raw material dibenzothiophene-3-boric acid was replaced with thianthracene-2-boric acid (compound 70).

[0084] Synthesis of Compounds 71-80: Compounds 71-80 were synthesized similarly to Compounds 1-10, except that the following steps were taken: 2,8-dibromodibenzothiophene was replaced with 2,7-dibromodibenzo[b,e][1,4]thiaselenoline (Compound 71); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromodibenzo[b,e][1,4]thiaselenoline (Compound 72); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromodibenzo[b,e][1,4]thiaselenoline (Compound 73); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromodibenzo[b,e][1,4]thiaselenoline (Compound 74); 2,8-dibromodibenzothiophene was replaced with... The following compounds were used: 2,7-dibromodibenzo[b,e][1,4]thioselenoline (compound 75); dibenzothiophene-2-boric acid was replaced with dibenzo[b,e][1,4]thioselen-3-boric acid (compound 76); dibenzothiophene-2-boric acid was replaced with dibenzo[b,e][1,4]thioselen-2-boric acid (compound 77); 2,8-dibromodibenzothiophene was replaced with 2,7-dibromodibenzo[b,e][1,4]thioselenoline (compound 78); dibenzothiophene-2-boric acid was replaced with dibenzo[b,e][1,4]thioselen-3-boric acid (compound 79); dibenzothiophene-3-boric acid was replaced with dibenzo[b,e][1,4]thioselen-2-boric acid (compound 80).

[0085] Synthesis of Compounds 81-90: Compounds 81-90 were synthesized similarly to Compounds 1-10, except that the following steps were taken: 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9-thioxanthone (Compound 81); 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9-thioxanthone (Compound 82); 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9-thioxanthone (Compound 83); 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9-thioxanthone (Compound 84); 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9-thioxanthone. - Dibromodibenzothiophene is replaced with 3,6-dibromo-9-thioxanone (compound 85); the raw material dibenzothiophene-2-boric acid is replaced with 9-thioxanone-3-boric acid (compound 86); the raw material dibenzothiophene-2-boric acid is replaced with 9-thioxanone-3-boric acid (compound 87); the raw material 2,8-dibromodibenzothiophene is replaced with 3,6-dibromo-9-thioxanone (compound 88); the raw material dibenzothiophene-2-boric acid is replaced with 9-thioxanone-3-boric acid (compound 89); the raw material dibenzothiophene-3-boric acid is replaced with 9-thioxanone-3-boric acid (compound 90).

[0086] Synthesis of Compounds 91-100: Compounds 91-100 were synthesized similarly to Compounds 1-10, except that: 2,8-dibromodibenzothiophene was replaced with 2,6-dibromo-9-selenoxanthophene (Compound 91); 3,9'-bicarbazole was replaced with 3,6-(dicarbazole)tricarbazole, and 2,8-dibromodibenzothiophene was replaced with 2,7-dibromo-9-selenoxanthophene (Compound 92); 3,9'-bicarbazole was replaced with 3,6-(dicarbazole)tricarbazole, and 2,8-dibromodibenzothiophene was replaced with 2,6-dibromo-9-selenoxanthophene (Compound 93); 2,8-dibromodibenzothiophene was replaced with... 2,6-Dibromo-9-selenoxone (Compound 94); 2,8-Dibromodibenzothiophene was replaced with 2,6-dibromo-9-selenoxone (Compound 95); dibenzothiophene-2-boric acid was replaced with 9-selenoxone-3-boric acid (Compound 96); dibenzothiophene-2-boric acid was replaced with 9-selenoxone-2-boric acid (Compound 97); 2,8-Dibromodibenzothiophene was replaced with 2,6-dibromo-9-selenoxone (Compound 98); dibenzothiophene-2-boric acid was replaced with 9-selenoxone-2-boric acid (Compound 99); dibenzothiophene-3-boric acid was replaced with 9-selenoxone-3-boric acid (Compound 100).

[0087] Synthesis of Compounds 101-110: Compounds 101-110 were synthesized similarly to Compounds 1-10, except that the following steps were taken: 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9,9-dimethylthiophene (Compound 101); 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9,9-dimethylthiophene (Compound 102); 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9,9-dimethylthiophene (Compound 103); 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9,9-dimethylthiophene (Compound 104 ...5); 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9,9-dimethylthiophene (Compound 106); 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9,9-dimethylthiophene (Compound 104); 2,8-dibromodibenzothiophene was replaced with 3,6-dibromodibenzothiophene (Compound 105); 2,8-dibromodibenzothiophene was replaced with 3,6-dibromodibenzothiophene (Compound 106); 2,8-dibromodibenzothiophene was replaced with 3,6-dibromodibenzothiophene (Comp Dibenzothiophene was replaced with 3,6-dibromo-9,9-dimethylthioxanthate (compound 105); the raw material dibenzothiophene-2-boric acid was replaced with 9,9-dimethylthioxanth-3-boric acid (compound 106); the raw material dibenzothiophene-2-boric acid was replaced with 9,9-dimethylthioxanth-3-boric acid (compound 107); the raw material 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9,9-dimethylthioxanthate (compound 108); the raw material dibenzothiophene-2-boric acid was replaced with 9,9-dimethylthioxanth-3-boric acid (compound 109); the raw material dibenzothiophene-3-boric acid was replaced with 9,9-dimethylthioxanth-3-boric acid (compound 110).

[0088] Synthesis of Compounds 111-120: Compounds 111-120 were synthesized similarly to Compounds 1-10, except that: 2,8-dibromodibenzothiophene was replaced with 2,6-dibromo-9,9-dimethylselenoxane (Compound 111); 3,9'-bicarbazole was replaced with 3,6-(dicarbazole)tricarbazole, and 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9,9-dimethylselenoxane (Compound 112); 3,9'-bicarbazole was replaced with 3,6-(dicarbazole)tricarbazole, and 2,8-dibromodibenzothiophene was replaced with 3,6-dibromo-9,9-dimethylselenoxane (Compound 113); 2,8-dibromodibenzothiophene was replaced with 2,6-dibromo-9,9-dimethylselenoxane (Compound 113); 1,9-Dimethylselenoxane (Compound 114); 2,8-dibromodibenzothiophene was replaced with 2,6-dibromo-9,9-dimethylselenoxane (Compound 115); dibenzothiophene-2-boric acid was replaced with 9,9-dimethylselenoxane-3-boric acid (Compound 116); dibenzothiophene-2-boric acid was replaced with 9,9-dimethylselenoxane-3-boric acid (Compound 117); 2,8-dibromodibenzothiophene was replaced with 2,6-dibromo-9,9-dimethylselenoxane (Compound 118); dibenzothiophene-2-boric acid was replaced with 9,9-dimethylselenoxane-3-boric acid (Compound 119); dibenzothiophene-3-boric acid was replaced with 9,9-dimethylselenoxane-3-boric acid (Compound 120).

[0089] Mass spectra of the above intermediates [M] + The values ​​are listed in Table 1.

[0090] Table 1

[0091] Mass spectra of the above compounds [M] + The values ​​are listed in Table 2.

[0092] Table 2

[0093] Example 2: Fabrication of electroluminescent devices using the compounds of the present invention as the host material. The compounds in this invention are sublimated and purified, and then electroluminescent devices are prepared by the following method.

[0094] (1) Fabrication of device 2-1 A glass substrate coated with 130 nm thick indium tin oxide (ITO) was sequentially ultrasonically cleaned for 10 minutes each with acetone, isopropanol, and ethanol. Next, the ITO substrate was ultrasonically cleaned for 10 minutes each with deionized hot water (60 °C) containing a cleaning agent. The ultrasonic cleaning process was then repeated twice with deionized water for 10 minutes each time. Finally, the ITO substrate was ultrasonically cleaned for 5 minutes with anhydrous ethanol and dried under an infrared lamp in a clean bench. Before device fabrication, the ITO substrate was transferred to a UV ozone cleaner and cleaned with UV ozone for 15 minutes, then transferred to a high-vacuum evaporation chamber.

[0095]

[0096] First, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene (HATCN, chemical formula as above) was vacuum thermally vaporized and deposited on the above ITO substrate with a deposition thickness of 8 nm as a hole injection layer.

[0097] Using 4,4-cyclohexyldi[ N,N [-Di(4-methylphenyl)aniline] (TAPC, chemical formula as above) was vacuum thermally vaporized and deposited on the hole injection layer to a thickness of 30 nm, serving as a hole transport layer.

[0098] Next, 4,4',4''-tris(carbazole-9-yl)triphenylamine (TCTA, chemical formula as above) was vacuum thermally vaporized and deposited on the hole transport layer to a thickness of 10 nm as an exciton / electron blocking layer.

[0099]

[0100] Subsequently, compound 1 was used as the host material and the common TADF dye DtBuCzB (chemical formula as above) as the luminescent dye. A mixture of compound 1 and DtBuCzB in a mass ratio of 98:2 was vacuum thermally evaporated and co-deposited on the exciton / electron blocking layer to a thickness of 20 nm, thereby forming the luminescent layer.

[0101] Then, 1,3,5-tris[(3-pyridyl)-3-phenyl]benzene (TmPyPB, chemical formula as above) was vacuum thermally vaporized and deposited on the above-mentioned light-emitting layer with a deposition thickness of 30 nm as an electron transport layer.

[0102] Finally, lithium fluoride (1 nm deposition thickness) and aluminum (120 nm deposition thickness) were sequentially deposited on the electron transport layer, serving as the electron injection layer and cathode, respectively.

[0103] During the thermal evaporation process of the above materials, the deposition rate of the hole injection layer material HATCN, the hole transport layer material TAPC, the exciton / electron blocking layer material TATC, the light-emitting layer and the electron transport layer material TmPyPB is maintained at 1. The deposition rate of lithium fluoride, the electron injection layer material, remained at 0.1 Å / s. The deposition rate of the electrode material, metallic aluminum, remained at 0.2 Å / s. 5 Å / s. During the thermal evaporation deposition process of all materials, the vacuum in the evaporation chamber was maintained at 5 × 10⁻⁶ Å / s. -4 Below Pa, electroluminescent devices can be manufactured.

[0104] (2) Fabrication of devices 2-2 to 2-48 The fabrication of devices 2-2 to 2-48 is the same as that of device 2-1, except that compound 1 in the light-emitting layer is replaced with other compounds in Table 3.

[0105] (3) Fabrication of contrast devices R1 and R2 The fabrication of devices R1 and R2 is the same as that of device 2-1, except that compound 1 in the light-emitting layer is replaced with mCBP or SF3-TRZ (chemical formulas are as follows).

[0106]

[0107] The device performance data obtained after applying current to the light-emitting device are detailed in Table 3.

[0108] Table 3

[0109] As shown in Table 3, compared to the comparative devices R1 and R2 prepared using common commercial host materials mCBP or SF3-TRZ that do not contain S and Se heavy atoms, the devices prepared using the compounds obtained in this invention as host materials exhibit high luminous efficiency and low efficiency roll-off (devices 2-1 to 2-48). It can be determined that the compounds defined by the general formula of this invention possess excellent host material properties, and the light-emitting devices prepared based on the host materials of this invention have superior properties such as high luminous efficiency and low efficiency roll-off.

[0110] Example 3: Fabrication of light-emitting devices using the compounds of the present invention as the host material. The compounds in this invention are sublimated and purified, and then electroluminescent devices are prepared using the compounds of this invention as the main material by the following method.

[0111] (1) Fabrication of device 3-1 The fabrication of device 3-1 is similar to that of device 2-1 in Example 2, except that the fabrication of the light-emitting layer is changed as follows: Compound 1 was used as the main material and the common TADF dye DtBuCzB-mFPh (chemical formula below) was used as the luminescent dye. A mixture of compound 1 and DtBuCzB-mFPh in a mass ratio of 98:2 was vacuum thermally evaporated and co-deposited on an exciton / electron blocking layer with a deposition thickness of 20 nm, thereby forming the luminescent layer.

[0112]

[0113] (2) Fabrication of devices 3-2 to 3-12 The fabrication of devices 3-2 to 3-12 is the same as that of device 3-1, except that compound 1 in the light-emitting layer is replaced with other compounds in Table 4.

[0114] (3) Fabrication of contrast devices R3 and R4 The fabrication of devices R3 and R4 is the same as that of device 3-1, except that compound 1 in the light-emitting layer is replaced with mCBP or SF3-TRZ.

[0115] The device performance data obtained after applying current to the light-emitting device are detailed in Table 4.

[0116] Table 4

[0117] As shown in Table 4, light-emitting devices were prepared using the compounds described in this invention as the host material and DtBuCzB-mFPh as the TADF luminescent dye. Compared to light-emitting devices R3 and R4 prepared using common commercial mCBP or SF3-TRZ host materials that do not contain S or Se heavy atoms, the resulting light-emitting devices 3-1 to 3-12 exhibit superior performance such as high device efficiency and low efficiency roll-off. Therefore, it can be further determined that the compounds defined by the general formula of this invention have excellent host material properties, and the light-emitting devices prepared based on the host materials of this invention have superior performance such as high luminous efficiency and low efficiency roll-off.

[0118] Example 4: Fabrication of light-emitting devices using the compounds of the present invention as the host material. (1) Fabrication of device 4-1 The fabrication of device 4-1 is similar to that of device 2-1 in Example 2, except that the fabrication of the light-emitting layer is changed as follows: Compound 4 was used as the host material and the common TADF dye 4CzIPN (chemical formula below) was used as the luminescent dye. A mixture of compound 4 and 4CzIPN in a mass ratio of 95:5 was vacuum thermally evaporated and co-deposited on an exciton / electron blocking layer with a deposition thickness of 20 nm, thereby forming the luminescent layer.

[0119] (2) Fabrication of devices 4-2 and 4-3 The fabrication of devices 4-2 and 4-3 is similar to that of device 4-1, except that the main material in the light-emitting layer is replaced with compounds 19 and 12, respectively, and the TADF dye is replaced with BN2 and DACT-II (chemical formulas as follows).

[0120]

[0121] (3) Fabrication of contrast devices R5-R10 The fabrication of devices R5-R10 is similar to that of devices 4-1, 4-2, and 4-3, except that compounds 4, 19, and 12 in the luminescent layer are replaced with mCBP or SF3-TRZ.

[0122] The device performance data obtained after applying current to the light-emitting device are detailed in Table 5.

[0123] Table 5

[0124] As shown in Table 5, light-emitting devices were prepared using the compounds of this invention as host materials and 4CzIPN, BN2, or DACT-II as TADF luminescent dyes. Compared to light-emitting devices R5-R10 prepared using common commercial mCBP or SF3-TRZ host materials that do not contain S or Se heavy atoms, the resulting light-emitting devices 4-1 to 4-3 exhibit superior performance such as high device efficiency and low efficiency roll-off. Therefore, it can be further determined that the compounds defined by the general formula of this invention have excellent host material properties, and the light-emitting devices prepared based on the host materials of this invention have superior performance such as high luminous efficiency and low efficiency roll-off.

[0125] In summary, the compounds of general formulas (1)-(13) described in this invention can be used as host materials in organic electroluminescent devices, and the prepared devices exhibit excellent performance such as high efficiency and low efficiency roll-off. The compounds of general formulas (1)-(13) of this invention all contain S or Se heavy atoms, and as host materials, they can form excitocomplexes with the corresponding TADF dyes. The triplet state of this excitocomplex can effectively promote inter-system crossing of the TADF dye as an intermediate state, improving the luminous efficiency of the device and significantly suppressing the efficiency roll-off. Using compounds from at least one exemplary embodiment of this specification as host materials and several common TADF dyes, electroluminescent devices with high efficiency and low efficiency roll-off can be realized.

[0126] The compounds having general formulas (1)-(13) described in this specification can be used as materials for hole injection, hole transport, luminescence, electron transport, electron blocking or electron injection.

[0127] The above embodiments are only used to help illustrate the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A host material characterized by: The structural formula is shown in general formula (1) as follows: General formula (1) Wherein, X is S or Se, Y is a direct bond, O, S, C=O or C(CH3)2; R1 and R2 represent an electron-rich group having hole transport ability or an electron-deficient group having electron transport ability.

2. The host material of claim 1, wherein: The general formula (1) includes general formula (2)-(13) as follows: 。 3. The host material according to claim 1 or 2, characterized in that: R1 and R2 are each independently selected from the group consisting of arylamine, alkyl-, alkoxy- or aryl-substituted arylamine, carbazolyl, alkyl-, alkoxy-, aryl- or arylamine-substituted carbazolyl, 9,10-dihydroacridinyl, phenoxazinyl, alkyl-, alkoxy- or aryl-substituted phenoxazinyl, phenothiazinyl, alkyl-, alkoxy- or aryl-substituted phenothiazinyl, pyridyl, aryl-substituted pyridyl, pyrimidyl, aryl-substituted pyrimidyl, triazinyl, aryl-substituted triazinyl, benzophenonyl, aryl-substituted benzophenonyl, xanthonyl, aryl-substituted xanthonyl, spirofluorenyl, aryl-substituted spirofluorenyl.

4. The host material according to claim 1 or 2, characterized in that: R1 and R2 are each independently selected from the group consisting of: ； wherein R3 R 30 each independently is selected from the group consisting of hydrogen, alkyl, cycloalkyl, alkoxy, aryl, alkyl-, cycloalkyl- or alkoxy-substituted aryl, alkyl-, cycloalkyl- or alkoxy-substituted heteroaryl, alkyl-, cycloalkyl- or alkoxy-substituted heterocyclyl.

5. The host material according to claim 1 or 2, characterized by: R1 and R2 are each independently selected from the group consisting of: 。 6. The host material according to claim 1 or 2, characterized by: selected from the group consisting of compounds shown in the structures (1)-(120) as follows: 。 7. Use of the host material according to any one of claims 1-6 in the preparation of an electroluminescent device.

8. Use according to claim 7, characterized in that: The host material according to any one of claims 1-6 is doped with a TADF dye and used in the preparation of a light-emitting functional layer of an electroluminescent device.

9. An electroluminescent device, characterized by: It comprises an anode, a cathode and a hole injection layer, a hole transport layer, an exciton / electron blocking layer, a light-emitting functional layer, an electron transport layer and an electron injection layer between the two electrodes; the light-emitting functional layer comprises the host material according to any one of claims 1-6.

10. The electroluminescent device according to claim 9, characterized in that: It also comprises an organic functional layer.

Images