A thermally activated delayed fluorescence material based on intramolecular self-sensitization and a preparation method and application thereof

Abstract

The application discloses a kind of heat-activated delayed fluorescence material based on intramolecular self-sensitization and its preparation method and application.The heat-activated delayed fluorescence material in the application includes at least one of the complex as shown in formula I or formula II: wherein, A unit includes several saturated or unsaturated polycyclic ring conjugated fused structure, each polycyclic ring is independently selected from five-membered ring or six-membered ring, wherein, at least two polycyclic rings are N and B-containing heterocyclic ring, and at least three polycyclic rings are aromatic ring;M is independently selected from Pt (II) or Pd (II) for each occurrence;The application has higher reverse intersystem crossing (RISC) rate, and application prospect is good.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent materials technology, specifically relating to a thermally activated delayed fluorescence material based on intramolecular self-sensitization, its preparation method, and its application. Background Technology

[0002] In recent years, high-quality displays have evolved from simple "output devices" into crucial bridges connecting digital content and real-world experiences. Thermally activated delayed fluorescence (TADF) captures triplet excitons through thermally driven reverse system crossing (RISC), thereby generating delayed fluorescence and providing high-performance luminescent materials for high-quality displays. However, its efficiency is often limited by a fundamental challenge: the reverse system crossing rate (kΩ). RISC The reverse intersystem crossing rate (RIR) of TADF luminescent materials is inherently low. Multiple resonance (MR) is one of the effective ways to improve the RIR of TADF luminescent materials, enabling a shift and upgrade from "passively relying on intrinsic material properties" to "actively designing and manipulating exciton fate." However, the RIR of current thermally activated delayed fluorescence materials is increasingly unable to meet the demands of higher-quality displays, making the development of TADF materials with higher RIR rates imperative. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a thermally activated delayed fluorescence material that can achieve a higher reverse intersystem crossing rate and has good application prospects.

[0004] This invention also proposes a method for preparing thermally activated delayed fluorescence materials.

[0005] The present invention also proposes a light-emitting device.

[0006] In a first aspect, the present invention provides a thermally activated delayed fluorescence material comprising at least one of the complexes shown in Formula I or Formula II: Unit A comprises a conjugated fused structure containing a plurality of saturated or unsaturated multi-membered rings, each of the multi-membered rings being independently selected from five-membered or six-membered rings, wherein at least two of the multi-membered rings are heterocycles containing N and B, and at least three of the multi-membered rings are aromatic rings; Each occurrence of M is independently selected from either Pt(II) or Pd(II); Each occurrence of R' is independently selected from hydrogen, deuterium, hydroxyl, mercapto, halogen group, cyano, acyl, substituted or unsubstituted amino, substituted or unsubstituted hydrocarbon, substituted or unsubstituted alkoxy, substituted or unsubstituted alkylthio, substituted or unsubstituted silyl, substituted or unsubstituted aryl. m is an integer, and each occurrence of m is independently selected from 1 to 10.

[0007] The thermally activated delayed fluorescence material according to embodiments of the present invention has at least the following beneficial effects: The thermally activated delayed fluorescence material of this invention, by connecting the A unit to a Pt(II) phosphorescent complex or a Pd(II) phosphorescent complex (e.g., through a coupling reaction), not only enhances the reverse intersystem crossing rate (k) of its hybrid molecules through intramolecular energy transfer, but also... RISC Furthermore, it can effectively reduce its roll-off rate, making it suitable for use in organic light-emitting devices. For example, it has promising applications in high-efficiency organic light-emitting diodes (OLEDs). In some embodiments of this invention, OLEDs were fabricated using thermally activated delayed fluorescence materials as emitters. It is evident that the introduction of thermally activated delayed fluorescence materials overcomes the limitations of the thermal activation mechanism, opening up a new intramolecular pathway for achieving triplet-singlet exciton conversion. Its synergistic effect significantly improves the utilization efficiency of triplet excitons, especially exhibiting excellent performance under high brightness conditions.

[0008] In some embodiments of the present invention, each occurrence of R' is independently selected from hydrogen, deuterium, hydroxyl, mercapto, halogen group, cyano, ester group, amide group, substituted or unsubstituted amino group, substituted or unsubstituted C1-C1 groups. 10 Alkyl, substituted or unsubstituted C1~C 10 alkenyl, substituted or unsubstituted C1~C 10 alkynyl, substituted or unsubstituted C1~C 10 alkoxy, substituted or unsubstituted C1~C 10 Silyl, substituted or unsubstituted C1~C 10 The substituted amino group may be alkylthioyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted pyridyl, substituted or unsubstituted furanyl, or substituted or unsubstituted indolyl. Optionally, the substituted amino group may include monosubstituted or disubstituted amino groups. Optionally, the substituted alkyl group may be selected from fluoroalkyl groups, such as trifluoromethyl, difluoromethyl, etc.

[0009] In some embodiments of the present invention, when R' is a substituted amino group, a substituted hydrocarbon group, a substituted alkoxy group, a substituted alkathio group, a substituted silyl group, or a substituted aryl group, the substituent group is selected from hydroxyl, mercapto, halogen group, cyano, ester group, amide group, amino, C1~C1. 10 Alkyl, C1~C 10 alkenyl, C1~C 10 alkynyl group, C1~C 10 alkoxy groups, C1~C 10 Silyl groups, C1~C 10 The alkylthio, phenyl, naphthyl, pyridyl, furanyl, or indoleyl groups.

[0010] In some embodiments of the present invention, the formula I complex is: .

[0011] In some embodiments of the present invention, the formula II complex is: .

[0012] In some embodiments of the present invention, the A unit includes at least one of the following structures:

[0013] Each time the group R appears, it is independently selected from hydrogen, deuterium, hydroxyl, mercapto, halogen group, cyano, acyl, substituted or unsubstituted amino, substituted or unsubstituted hydrocarbon, substituted or unsubstituted alkoxy, substituted or unsubstituted alkylthio, substituted or unsubstituted silyl, substituted or unsubstituted aryl. The r is an integer, and each occurrence of r is independently selected from 0 to 10; when r is 0, it indicates that unit A does not contain the group L; Each occurrence of the group L is independently selected from O, S, N, and -(CH2). n -or At least one of the following, where n is an integer and each occurrence of n is independently selected from 1 to 10.

[0014] Through the above implementation methods, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) on the rigid π-conjugated framework are localized to different atoms (such as boron and nitrogen), and the extremely narrow band gap allows excitons to efficiently migrate from the triplet state (T1) to the singlet state (S1) via thermal energy. Based on the multiple resonance thermally activated delayed fluorescence (MR-TADF) framework, both expanding the conjugation range of the MR framework and the strong SOC effect induced by the twisted structure can promote the RISC process. Moreover, the synthesis method of thermally activated delayed fluorescence materials is simple, and different structures based on the pre-defined thermally activated delayed fluorescence materials can be rapidly synthesized, showing broad development potential. In some embodiments of the present invention, when the group R is a substituted amino group, a substituted hydrocarbon group, a substituted alkoxy group, a substituted alkathio group, a substituted silyl group, or a substituted aryl group, the substituted group is selected from hydroxyl, mercapto, halogen group, cyano, ester group, amide group, amino, C1~C1. 10 Alkyl, C1~C 10 alkenyl, C1~C 10 alkynyl group, C1~C 10 alkoxy groups, C1~C 10 Silyl groups, C1~C 10 The alkylthio, phenyl, naphthyl, pyridyl, furanyl, or indoleyl groups.

[0015] In some embodiments of the present invention, each occurrence of the group R is independently selected from hydrogen, deuterium, hydroxyl, mercapto, halogen group, cyano, ester, amide, substituted or unsubstituted amino group, substituted or unsubstituted C1-C1 group. 10 Alkyl, substituted or unsubstituted C1~C 10 alkenyl, substituted or unsubstituted C1~C 10 alkynyl, substituted or unsubstituted C1~C 10 alkoxy, substituted or unsubstituted C1~C 10 Silyl, substituted or unsubstituted C1~C 10 The substituted amino group may be an alkylthio group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted pyridyl group, a substituted or unsubstituted furanyl group, or a substituted or unsubstituted indolyl group. Optionally, the substituted amino group may include a monosubstituted or disubstituted amino group. Optionally, the substituted alkyl group may be a fluoroalkyl group, such as a trifluoromethyl group, a difluoromethyl group, etc.

[0016] In some embodiments of the present invention, each occurrence of the group R is independently selected from hydrogen, deuterium, hydroxyl, mercapto, halogen group, cyano, substituted or unsubstituted C1-C. 10 Alkyl, substituted or unsubstituted C1~C 10 alkenyl, substituted or unsubstituted C1~C 10 alkynyl, substituted or unsubstituted C1~C 10 alkoxy groups.

[0017] In some embodiments of the present invention, each occurrence of the group R is independently selected from hydrogen, deuterium, hydroxyl, mercapto, halogen group, cyano, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy.

[0018] In some embodiments of the present invention, each occurrence of the group R is independently selected from hydrogen or tert-butyl.

[0019] In some embodiments of the present invention, the Formula I complex includes at least one of a meridional structure or a planar structure. The Formula II complex includes at least one of a meridional structure or a planar structure.

[0020] In some embodiments of the present invention, the Formula I complex includes at least one of the following complexes:

[0021]

[0022]

[0023]

[0024]

[0025]

[0026] .

[0027] In some embodiments of the present invention, the formula II complex includes at least one of the following complexes:

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039] .

[0040] In some embodiments of the present invention, the thermally activated delayed fluorescence material is selected from at least one of the following complexes: .

[0041] A second aspect of the present invention provides a method for preparing a thermally activated delayed fluorescence material, comprising the following steps: S2, the raw materials containing the metal M precursor and ligand are mixed and heated to obtain the thermally activated delayed fluorescence material, wherein the ligand includes at least one of the complexes shown in Formula I' or Formula II': .

[0042] In some embodiments of the present invention, the metal element M is selected from platinum or palladium.

[0043] In some embodiments of the present invention, the metal M precursor includes at least one of (1,5-cyclooctadiene)platinum dichloride (Pt(COD)Cl2), platinum chloride (PtCl2), potassium tetrachloroplatinate(II) (K2PtCl4), platinum acetate (PtOAc)2, (1,5-cyclooctadiene)palladium dichloride (Pd(COD)Cl2), palladium chloride (PdCl2), potassium tetrachloropalladium(II) (K2PdCl4), or palladium acetate (PdOAc)2.

[0044] In this invention, the M precursor is integrated into the multiple resonance thermally activated delayed fluorescence (MR-TADF) framework. Because the emission wavelength of the M precursor overlaps with the absorption wavelength of the MR-TADF component, energy can be transferred to the emission state of the MR-TADF component in the excited state via a platinum (II) or Pd (II) medium. Furthermore, the synthesis method of the thermally activated delayed fluorescence material is simple, and thermally activated delayed fluorescence materials based on a pre-defined structure can be rapidly synthesized, indicating broad development potential. In some embodiments of the present invention, the heating temperature is 80~200℃, such as 100~180℃.

[0045] In some embodiments of the present invention, the heating reaction time is 24~100h, or optionally 24~72h.

[0046] In some embodiments of the present invention, the heating reaction in step S2 is carried out under a protective atmosphere. Unless otherwise specified herein, the protective atmosphere includes at least one of nitrogen or an inert gas.

[0047] In some embodiments of the present invention, the molar ratio of the metal M precursor to the ligand is (1~10):1.

[0048] In some embodiments of the present invention, the raw materials for preparation further include solvent I.

[0049] In some embodiments of the present invention, solvent I includes at least one of acetic acid, formic acid, propionic acid, or oxalic acid.

[0050] In some embodiments of the present invention, the ratio of the amount of the metal M precursor to the amount of solvent I is (0.01~2) mol:1 L, such as (0.02~2) mol:1 L.

[0051] In some embodiments of the present invention, in step S2, the raw materials for preparation further include tetrabutylammonium bromide, and optionally, the molar ratio of the tetrabutylammonium bromide to the ligand is 1:(5~50).

[0052] In some embodiments of the present invention, in step S2, the raw material is heated and then purified to obtain the thermally activated delayed fluorescence material. Optionally, the purification method includes, but is not limited to, washing, extraction, recrystallization, and column chromatography, or one or more of these. Optionally, the extraction solvent used in the extraction includes at least one of dichloromethane, ethyl acetate, and water; the recrystallization solvent used in the recrystallization includes methanol; and the eluent used in the column chromatography includes petroleum ether / dichloromethane or dichloromethane / a small amount of polar solvent.

[0053] In some embodiments of the present invention, the preparation method further includes preparing the ligand, specifically including: S1, the raw materials containing compound A and compound B are mixed and subjected to a Suzuki coupling reaction to obtain the ligand, wherein compound B includes at least one of the compounds shown in formula B-1 or formula B-2: Each time X appears, it is independently selected from F, Cl, Br, or I.

[0054] In some embodiments of the present invention, the molar ratio of compound B to compound A is 1:(0.5~3).

[0055] In some embodiments of the present invention, in step S1, the raw materials for preparation include catalyst I and an alkaline substance.

[0056] In some embodiments of the present invention, the catalyst I comprises at least one of tris(dibenzylacetone)palladium, tetra(triphenylphosphine)palladium, bis(benzylacetone)palladium, palladium acetate, bis(triphenylphosphine)palladium dichloride, or 1,1'-bis(diphenylphosphine)ferrocene palladium dichloride.

[0057] In some embodiments of the present invention, the molar ratio of compound B to catalyst I is 1:(0.001~0.2), or optionally 1:(0.001~0.1).

[0058] In some embodiments of the present invention, the alkaline substance includes at least one of potassium carbonate, sodium carbonate, lithium carbonate, cesium carbonate, potassium acetate, sodium acetate, lithium acetate, cesium acetate, potassium tert-butoxide, sodium tert-butoxide, lithium tert-butoxide, cesium tert-butoxide, triethylamine, trimethylamine, DBU, TBD, MTBD, or diisopropylethylenediamine.

[0059] Among them, DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene; TBD: 1,5,7-triazabicyclo[4.4.0]dec-5-ene; MTBD: 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene.

[0060] In some embodiments of the present invention, the molar ratio of compound B to the alkaline substance is 1:(2~20), or optionally 1:(3~10).

[0061] In some embodiments of the present invention, in step S1, the raw materials for preparation further include 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl. Optionally, the molar ratio of compound A to 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl is 1:(0.1~0.5).

[0062] In some embodiments of the present invention, in step S1, the raw material for preparation includes solvent II. Optionally, the boiling point of solvent II is 80~200℃.

[0063] In some embodiments of the present invention, solvent II comprises at least one selected from ethanol, water, 1,4-dioxane, chlorobenzene, dichlorobenzene, or alkyl-substituted benzene. Optionally, the alkyl-substituted benzene comprises at least one selected from toluene, xylene, ethylbenzene, diethylbenzene, propylbenzene, butadiene, or pentamene.

[0064] In some embodiments of the present invention, the ratio of compound B to solvent II is 1 mol:(3~50) L.

[0065] In some embodiments of the present invention, in step S1, the reaction temperature of the Suzuki coupling reaction is 80~160°C, or optionally 80~120°C.

[0066] In some embodiments of the present invention, in step S1, the reaction time of the Suzuki coupling reaction is 4 to 80 hours, or optionally 12 to 40 hours.

[0067] In some embodiments of the invention, in step S1, the Suzuki coupling reaction is carried out in a protective atmosphere. Optionally, the gas in the protective atmosphere includes nitrogen.

[0068] In some embodiments of the present invention, in step S1, the raw materials are purified after undergoing a Suzuki coupling reaction to obtain the thermally activated delayed fluorescence material. Optionally, the purification method includes, but is not limited to, one or more of washing, extraction, recrystallization, and column chromatography. In some embodiments of the present invention, in step S1, the mixture obtained after the Suzuki coupling reaction is diluted with ethyl acetate, filtered through diatomaceous earth to remove inorganic salts and catalyst I residue, and the filter cake is washed with ethyl acetate. The filtrates are combined and washed with water, the organic phase is dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product obtained is purified by silica gel column chromatography to obtain the ligand.

[0069] In some embodiments of the present invention, compound A is selected from at least one of compound A-1 or compound A-2: .

[0070] In some embodiments of the present invention, the preparation method further includes a preparation step of compound A, specifically including: Sa-1, reacting the raw materials containing compound A' and pinacol diboronic acid ester under a protective atmosphere by heating, yields compound A, wherein compound A' is: ; X is selected from H, F, Cl, Br or I.

[0071] In some embodiments of the present invention, the molar ratio of compound A' to pinacol diboronate is 1:(0.5~20), or optionally 1:(1~20).

[0072] In some embodiments of the present invention, in step Sa-1, the raw materials for preparation further include catalyst II.

[0073] In some embodiments of the present invention, the catalyst II comprises at least one selected from 1,1'-bis(diphenylphosphine)ferrocene palladium(II) chloride, bis(1,5-cyclooctadiene)dimethoxyiridium, or bis(1,5-cyclooctadiene)iridium(II) chloride. Specifically, 1,1'-bis(diphenylphosphine)ferrocene palladium(II) chloride: Pd(dppf)Cl2.

[0074] In some embodiments of the present invention, the molar ratio of compound A' to catalyst II is 1:(0.001~0.1).

[0075] In some embodiments of the present invention, in step Sa-1, the raw materials for preparation further include KOAc. In some embodiments of the present invention, the molar ratio of catalyst II to KOAc is 1:(100~600).

[0076] In some embodiments of the present invention, in step Sa-1, the raw materials for preparation further include at least one of 4,4'-di-tert-butyl-2,2'-dipyridine, 4,7-diphenyl-1,10-phenanthroline, 4,7-dimethyl-1,10-phenanthroline, or 3,4,7,8-tetramethyl-1,10-phenanthroline.

[0077] In some embodiments of the present invention, the molar ratio of compound A' to 4,4'-di-tert-butyl-2,2'-dipyridine is 1:(0.005~0.5).

[0078] In some embodiments of the present invention, in step Sa-1, the raw materials for preparation further include solvent III.

[0079] In some embodiments of the present invention, solvent III comprises at least one of tetrahydrofuran, dioxane, dimethyl sulfoxide, N,N-dimethylformamide, or N,N-dimethylacetamide.

[0080] In some embodiments of the present invention, the ratio of compound A' to solvent III is (0.02~2) mol: 1 L.

[0081] In some embodiments of the present invention, in step Sa-1, the protective gas in the protective atmosphere includes nitrogen.

[0082] In some embodiments of the present invention, in step Sa-1, the temperature of the heating reaction is 60~150°C, or optionally 65~100°C.

[0083] In some embodiments of the present invention, in step Sa-1, the heating reaction time is 4 to 80 hours, or optionally 12 to 40 hours.

[0084] In some embodiments of the present invention, in step Sa-1, the mixture obtained after heating reaction is extracted with dichloromethane and deionized water, the combined organic phases are dried with anhydrous Na2SO4, filtered, and the solvent is removed by rotary evaporation under reduced pressure. The crude product obtained is purified by column chromatography to obtain compound A.

[0085] In some embodiments of the present invention, in step Sa-1, the mixture obtained after heating reaction is filtered through diatomaceous earth, the filter cake is washed with ethyl acetate, the solvent is collected and rotary evaporated to obtain crude product, which is then purified by silica gel column chromatography to obtain compound A.

[0086] In some embodiments of the present invention, compound A is compound A-2, and compound A' is prepared by a method comprising the following steps: The raw materials containing 1,4-dibromo-2,6-difluorobenzene, 3,6-di-tert-butylcarbazole, t-BuOK and DMF were stirred and reacted at 120~150℃ for 20~30h under nitrogen protection, and then separated and purified to obtain the brominated intermediate. The brominated intermediate was mixed with an n-BuLi hexane solution at -70℃ to -80℃, and the temperature was raised to 40 to 60℃; BBr3 was added at -25℃ to -35℃, and the temperature was raised to room temperature; DIPEA was added, and the temperature was raised to 120 to 140℃ to obtain compound A'.

[0087] In some embodiments of the present invention, the compound of formula B-1 is compound B-1-1, and the compound of formula B-2 is compound B-2-1: .

[0088] In some embodiments of the present invention, the preparation method further includes a preparation step of compound B-1-1, specifically including: S-b1-1-1, the raw materials containing 3-halophenol and 1-(3-halophenyl)-1H-pyrazole are heated and reacted under a protective atmosphere to obtain 1-[3-(3-halophenoxy)phenyl]-1H-pyrazole; S-b1-1-2, the preparation raw materials containing 1-[3-(3-halophenoxy)phenyl]-1H-pyrazole and 4-halopyrazole are heated and reacted under a protective atmosphere to obtain the compound B-1-1.

[0089] The structural formulas of 3-halophenol, 1-(3-halophenyl)-1H-pyrazole, and 1-[3-(3-halophenoxy)phenyl]-1H-pyrazole are as follows:

[0090] In some embodiments of the present invention, in step S-b1-1-1, the molar ratio of 3-halophenol to 1-(3-halophenyl)-1H-pyrazole is 1:(0.5~2.5).

[0091] In some embodiments of the present invention, the 3-halophenol includes at least one of 3-fluorophenol, 3-chlorophenol, 3-bromophenol, or 3-iodophenol.

[0092] In some embodiments of the present invention, the 1-(3-halophenyl)-1H-pyrazole includes at least one of 1-(3-fluorophenyl)-1H-pyrazole, 1-(3-chlorophenyl)-1H-pyrazole, 1-(3-bromophenyl)-1H-pyrazole or 1-(3-iodophenyl)-1H-pyrazole.

[0093] In some embodiments of the present invention, the 1-[3-(3-halophenoxy)phenyl]-1H-pyrazole includes at least one of 1-[3-(3-fluorophenoxy)phenyl]-1H-pyrazole, 1-[3-(3-chlorophenoxy)phenyl]-1H-pyrazole, 1-[3-(3-bromophenoxy)phenyl]-1H-pyrazole or 1-[3-(3-iodophenoxy)phenyl]-1H-pyrazole.

[0094] In some embodiments of the present invention, in step S-b1-1-1, the raw materials for preparation further include cuprous iodide, pyridinecarboxylic acid, potassium phosphate, and dimethyl sulfoxide.

[0095] In some embodiments of the present invention, in step S-b1-1-1, the ratio of the amounts of 3-halophenol, 1-(3-halophenyl)-1H-pyrazole, cuprous iodide, pyridinecarboxylic acid, potassium phosphate and dimethyl sulfoxide is 10 mmol:(5~25) mmol:(0.2~0.8) mmol:(0.5~2.5) mmol:(5~15) mmol:(10~30) mL.

[0096] In some embodiments of the present invention, in step S-b1-1-1, the temperature of the heating reaction is 70~160℃, or optionally 80~120℃.

[0097] In some embodiments of the present invention, in step S-b1-1-1, the heating reaction time is 10-80 hours, or optionally 36-60 hours.

[0098] In some embodiments of the present invention, in step S-b1-1-2, the molar ratio of 1-[3-(3-halophenoxy)phenyl]-1H-pyrazole to 4-halopyrazole is 1:(0.5~2.5).

[0099] In some embodiments of the present invention, in step S-b1-1-2, the raw materials for preparation further include cuprous iodide, L-proline, potassium carbonate, and dimethyl sulfoxide.

[0100] In some embodiments of the present invention, in step S-b1-1-2, the ratio of the amounts of 4-halopyrazole, 1-[3-(3-halophenoxy)phenyl]-1H-pyrazole, cuprous iodide, L-proline, potassium carbonate and dimethyl sulfoxide is 10 mmol:(5~25) mmol:(0.2~2) mmol:(1~3) mmol:(15~30) mmol:(10~30) mL.

[0101] In some embodiments of the present invention, in step S-b1-1-2, the temperature of the heating reaction is 70~160℃, or optionally 80~120℃.

[0102] In some embodiments of the present invention, in step S-b1-1-2, the heating reaction time is 10-80 h, or optionally 36-60 h.

[0103] In some embodiments of the present invention, the preparation method further includes a preparation step of compound B-1-1, specifically including: S-b1-2-1, the raw materials containing 4-halopyrazole and 3-halopyrphenol are heated and reacted under a protective atmosphere to obtain 3-(4-halopyrazole-1-yl)phenol; S-b1-2-2, the preparation raw materials containing 3-(4-halopyrazol-1-yl)phenol and 1-(3-halopyridine)-1H-pyrazole are heated and reacted under a protective atmosphere to obtain the compound B-1-1.

[0104] In some embodiments of the present invention, the 4-halopyrazole includes at least one of 4-fluopyrazole, 4-chloropyrazole, 4-bromopyrazole, or 4-iodopyrazole.

[0105] In some embodiments of the present invention, the 3-(4-halopyrazole-1-yl)phenol includes at least one of 3-(4-fluoropyrazole-1-yl)phenol, 3-(4-chloropyrazole-1-yl)phenol, 3-(4-bromopyrazole-1-yl)phenol, or 3-(4-iodopyrazole-1-yl)phenol.

[0106] In some embodiments of the present invention, the 1-(3-halophenyl)-1H-pyrazole includes at least one of 1-(3-fluorophenyl)-1H-pyrazole, 1-(3-chlorophenyl)-1H-pyrazole, 1-(3-bromophenyl)-1H-pyrazole, or 1-(3-iodophenyl)-1H-pyrazole.

[0107] In some embodiments of the present invention, in step S-b1-2-1, the molar ratio of 3-halophenol to 4-halopyrazole is 1:(0.5~2.5).

[0108] In some embodiments of the present invention, in step S-b1-2-1, the raw materials for preparation further include Cs2CO3, CuO, and solvent IV. Optionally, solvent IV includes at least one of N,N-dimethylformamide or dimethyl sulfoxide.

[0109] In some embodiments of the present invention, in step S-b1-2-1, the molar ratio of 3-halophenol, 4-halopyrazole, Cs2CO3 and CuO is 1:(0.5~2.5):(1~5):(0.02~0.5).

[0110] In some embodiments of the present invention, in step S-b1-2-1, the ratio of the amount of 3-halophenol to solvent IV is (0.02~2) mol: 1 L.

[0111] In some embodiments of the present invention, in step S-b1-2-1, the temperature of the heating reaction is 70~160℃, or optionally 80~120℃.

[0112] In some embodiments of the present invention, in step S-b1-2-1, the heating reaction time is 10~80h, or optionally 12~48h.

[0113] In some embodiments of the present invention, in step S-b1-2-2, the molar ratio of 3-(4-halopyrazole-1-yl)phenol to 1-(3-halopyridine)-1H-pyrazole is 1:(0.5~2.5).

[0114] In some embodiments of the present invention, in step S-b1-2-2, the raw materials for preparation further include 2-pyridinecarboxylic acid, potassium phosphate, cuprous iodide, and solvent V. Optionally, solvent V includes at least one of N,N-dimethylformamide or dimethyl sulfoxide.

[0115] In some embodiments of the present invention, in step S-b1-2-2, the molar ratio of 3-(4-halopyrazole-1-yl)phenol, 1-(3-halophenyl)-1H-pyrazole, 2-pyridinecarboxylic acid, potassium phosphate and cuprous iodide is 1:(0.5~3.5):(0.8~3.5):(0.5~5):(0.1~0.8).

[0116] In some embodiments of the present invention, in step S-b1-2-2, the ratio of the amount of 3-(4-halopyrazole-1-yl)phenol to solvent V is (0.02~2) mol: 1 L.

[0117] In some embodiments of the present invention, in step S-b1-2-2, the temperature of the heating reaction is 70~180℃, or optionally 100~160℃.

[0118] In some embodiments of the present invention, in step S-b1-2-2, the heating reaction time is 4~80h, or optionally 12~60h.

[0119] In some embodiments of the present invention, the preparation method further includes a preparation step of compound B-2-1, specifically including: S-b2-1, the raw materials containing 3-halophenol and 2-(3-halophenyl)pyridine are heated and reacted under a protective atmosphere to obtain 2-[3-(3-halophenoxy)phenyl]pyridine; S-b2-2, the raw materials containing 2-[3-(3-halophenoxy)phenyl]pyridine and pinacol ester of borate are heated and reacted under a protective atmosphere to obtain the aromatic ring-Bpin borate intermediate; S-b2-3, the preparation raw materials containing the aromatic ring-Bpin borate intermediate and 2,4-dihalopyridine are heated and reacted under a protective atmosphere to obtain compound B-2-1.

[0120] The structural formulas of 2-(3-halophenyl)pyridine, 2-[3-(3-halophenoxy)phenyl]pyridine, aromatic ring-Bpin borate intermediate, and 2,4-dihalopyridine are as follows: .

[0121] In some embodiments of the present invention, the 2-(3-halophenyl)pyridine includes at least one of 2-(3-fluorophenyl)pyridine, 2-(3-chlorophenyl)pyridine, 2-(3-bromophenyl)pyridine or 2-(3-iodophenyl)pyridine.

[0122] In some embodiments of the present invention, the 2-[3-(3-halophenoxy)phenyl]pyridine includes at least one of 2-[3-(3-fluorophenoxy)phenyl]pyridine, 2-[3-(3-chlorophenoxy)phenyl]pyridine, 2-[3-(3-bromophenoxy)phenyl]pyridine or 2-[3-(3-iodophenoxy)phenyl]pyridine.

[0123] In some embodiments of the present invention, the 2,4-dihalopyridine includes at least one of 2,4-difluoropyridine, 2,4-dichloropyridine, 2,4-dibromopyridine, or 2,4-diiodopyridine.

[0124] In some embodiments of the present invention, in step S-b2-1, the molar ratio of 3-halophenol to 2-(3-halophenyl)pyridine is 1:(0.5~2.5).

[0125] In some embodiments of the present invention, in step S-b2-1, the raw materials for preparation further include potassium phosphate, pyridinecarboxylic acid, cuprous iodide, and solvent VI. Optionally, solvent VI includes at least one of N,N-dimethylformamide or dimethyl sulfoxide.

[0126] In some embodiments of the present invention, in step S-b2-1, the ratio of the amounts of 3-halophenol, 2-(3-bromophenyl)pyridine, potassium phosphate, pyridinecarboxylic acid, cuprous iodide and solvent VI is 10 mmol:(5~25) mmol:(20~50) mmol:(1~3) mmol:(0.5~3) mmol:(10~30) mL.

[0127] In some embodiments of the present invention, in step S-b2-1, the temperature of the heating reaction is 80~160℃, or optionally 90~110℃.

[0128] In some embodiments of the present invention, in step S-b2-1, the heating reaction time is 4~80h, or optionally 12~40h.

[0129] In some embodiments of the present invention, in step S-b2-2, the molar ratio of 2-[3-(3-halophenoxy)phenyl]pyridine to pinacol diboronic acid ester is 1:(1~10).

[0130] In some embodiments of the present invention, in step S-b2-2, the raw materials for preparation further include Pd(dppf)Cl2, KOAc, and solvent VII. Optionally, solvent VII comprises 1,4-dioxane.

[0131] In some embodiments of the present invention, in step S-b2-2, the ratio of the amounts of 2-[3-(3-halophenoxy)phenyl]pyridine, pinacol diboronic acid ester, Pd(dppf)Cl2, KOAc and solvent VII is 10 mmol:(10~100) mmol:(0.1~1) mmol:(10~30) mmol:(5~50) mL.

[0132] In some embodiments of the present invention, in step S-b2-2, the temperature of the heating reaction is 60~130°C, or optionally 70~110°C.

[0133] In some embodiments of the present invention, in step S-b2-2, the heating reaction time is 4~80h, or optionally 12~40h.

[0134] In some embodiments of the present invention, in step S-b2-3, the molar ratio of the aromatic ring-Bpin borate intermediate to 2,4-dihalopyridine is 1:(1~10).

[0135] In some embodiments of the present invention, in steps S-b2-3, the raw materials for preparation further include Pd(PPh3)4, K2CO3, and solvent VIII. Optionally, solvent VIII includes at least one of water, benzene, toluene, or ethylbenzene.

[0136] In some embodiments of the present invention, in step S-b2-3, the ratio of the amount of the aromatic ring-Bpin borate intermediate, 2,4-dihalopyridine, Pd(PPh3)4, K2CO3 and solvent VIII is 10 mmol:(10~100) mmol:(0.1~1) mmol:(10~50) mmol:(5~50) mL.

[0137] In some embodiments of the present invention, in step S-b2-3, the temperature of the heating reaction is 60~150℃, or optionally 80~120℃.

[0138] In some embodiments of the present invention, in step S-b2-3, the heating reaction time is 4~80h, or optionally 12~40h.

[0139] In a third aspect, the present invention provides a light-emitting device comprising the thermally activated delayed fluorescence material described above.

[0140] In some embodiments of the present invention, the light-emitting device includes an electroluminescent device.

[0141] In some embodiments of the present invention, the light-emitting device includes an organic light-emitting diode. Attached Figure Description

[0142] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 The above is the 1H NMR spectrum of compound 3 in Example 1 of this invention; Figure 2 The image shows the carbon NMR spectrum of compound 3 in Example 1 of this invention. Figure 3 The 1H NMR spectrum of the complex DtBuCzB-Pt in Example 1 of this invention; Figure 4 The above is the 1H NMR spectrum of compound 6 in Example 2 of this invention; Figure 5 The image shows the carbon NMR spectrum of compound 6 in Example 2 of this invention. Figure 6 This is a schematic diagram of the single-crystal structure of the complex DABNA-Pt in Example 2 of the present invention; Figure 7 The 1H NMR spectrum of the complex DABNA-Pt in Example 2 of this invention; Figure 8 The image shows the carbon NMR spectrum of the complex DABNA-Pt in Example 2 of this invention. Figure 9 The 1H NMR spectrum of compound 11 in Example 3 of this invention; Figure 10 The image shows the carbon NMR spectrum of compound 11 in Example 3 of this invention. Figure 11 The 1H NMR spectrum of the complex DtBuCzB-Pd in ​​Example 3 of this invention; Figure 12The image shows the carbon NMR spectrum of the complex DtBuCzB-Pd in ​​Example 3 of this invention. Figure 13 The UV-Vis absorption and emission spectra of the DtBuCzB-Pt molecular fragment and the whole complex in Example 1 of this invention are shown. Figure 14 The UV-Vis absorption and emission spectra of the DABNA-Pt molecular fragment and the whole complex in Example 2 of this invention are shown. Figure 15 The UV-Vis absorption and emission spectra of the DtBuCzB-Pd molecular fragment and the whole complex in Example 3 of this invention are shown. Figure 16 This is a schematic diagram of the electroluminescent device in Embodiment 1 of the present invention; Figure 17 The figure shows the performance test results of the electroluminescent device prepared in Example 1 of the present invention. Detailed Implementation The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0143] Unless otherwise specified, the experimental methods described in the following examples are generally performed under conventional conditions in the art or as recommended by the manufacturer; the raw materials and reagents used are all commercially available from the conventional market unless otherwise specified.

[0144] Example 1 This embodiment discloses a thermally activated delayed fluorescence material, which is a platinum complex (DtBuCzB-Pt) with a di-tert-butylcarbazole boron backbone. Its preparation method includes the following steps: (I) The synthesis of the MR-TADF skeleton derivative (compound 3) includes the following steps:

[0145] Under a nitrogen atmosphere, compound 1, 1-(3-(3-(1H-pyrazol-1-yl)phenoxy)phenyl)-4-chloro-1H-pyrazole (0.51 g, 1.5 mmol, 1.0 equivalent), and compound 2, DtBuCzB-Bpin (1.15 g, 1.5 mmol, 1.0 equivalent), were added to 20 mL of a mixed solvent of toluene, ethanol, and water (volume ratio 7:1:2). Subsequently, tetrakis(triphenylphosphine)palladium (0.09 g, 0.075 mmol, 0.05 equivalent) and potassium carbonate (0.62 g, 4.5 mmol, 3.0 equivalent) were added to the reaction system. The system was heated from room temperature to 100 °C at a heating rate of 5 °C / min, and the reaction was carried out at 100 °C for 24 hours. After cooling to room temperature, the reaction mixture was diluted with 100 mL of ethyl acetate and washed with water. The organic phase was collected, concentrated under reduced pressure to remove the solvent, and then purified by silica gel column chromatography with petroleum ether / ethyl acetate (v / v 5:1) as the eluent to give the coupling product compound 3 (tert-butylcarbazole boron nitrogen-linked phenylpyrazole tetradentate ligand, 0.80 g, yield: 57%).

[0146] The proton and carbon spectra of compound 3 are as follows: Figures 1-2 As shown: 1 H NMR (500 MHz, CDCl3) δ 8.93 (s, 2H), 8.34 (s, 2H), 8.20 (d, J = 8.7Hz, 2H), 8.19 – 8.13 (m, 5H), 8.08 (s, 1H), 7.94 (d, J = 2.3 Hz, 1H), 7.73 (s,1H), 7.62 (dd, J = 6.0, 2.2 Hz, 3H), 7.59 – 7.47 (m, 5H), 7.05 (s, 2H), 6.54 –6.42 (m, 1H), 1.64 (s, 18H), 1.54 (s, 18H). 13C NMR (151 MHz, CDCl3) δ 158.00, 157.97, 145.24, 144.74, 144.49,141.82, 141.68, 141.55, 141.49, 139.55, 138.25, 136.12, 130.91, 130.89,129.69, 127.20, 127.01, 125.70, 124.45, 123.98, 123.54, 122.16, 121.71,120.57, 117.37, 117.09, 116.93, 114.30, 114.28, 114.14, 110.51, 110.34, 108.06, 105.28, 35.23, 34.91, 32.30, 31.98. (II) Synthesis of intramolecular sensitized platinum complex DtBuCzB-Pt (Pt(II) metallization), including the following steps:

[0147] Ligand-compound 3 (0.75 g, 0.8 mmol, 1.0 equivalent), potassium tetrachloroplatin(II) acid (0.42 g, 1.0 mmol, 1.25 equivalent), and tetrabutylammonium bromide (0.03 g, 0.08 mmol, 0.1 equivalent) were added to a two-necked flask equipped with a magnetic stirrer. The flask was then evacuated and purged with nitrogen, repeated three times. Acetic acid (35 mL) was added as a solvent under a nitrogen atmosphere. The mixture was placed in an oil bath and refluxed at 118 °C with stirring for three days (optionally, the temperature could be increased to 118 °C at a rate of 5 °C / min during reflux), then cooled to room temperature. Recrystallization was performed by adding 35 mL of methanol to the reaction mixture. The residue was purified by silica gel column chromatography using petroleum ether / dichloromethane (volume ratio 5:1~2:1) as eluent to obtain the target product complex 4—DtBuCzB-Pt (also known as: tert-butylcarbazole boron nitrogen-linked platinum complex), which was a yellow solid (0.23 g, yield: 25%).

[0148] The proton spectrum of DtBuCzB-Pt is as follows: Figure 3 As shown: 1 H NMR (500 MHz, CDCl3) δ 9.06 – 9.03 (m, 2H), 8.47 (t, J = 4.5 Hz, 4H), 8.45 (d, J = 1.6 Hz, 2H), 8.29 (d, J= 1.9 Hz, 2H), 8.21 (s, 1H), 7.94 (s,1H), 7.83 (s, 1H), 7.79 (d, J = 1.8 Hz, 1H), 7.77 (d, J = 1.8 Hz, 1H), 7.19(dt, J = 14.7, 7.9 Hz, 3H), 7.08 (d, J = 7.5 Hz, 2H), 7.05 – 7.01 (m, 2H), 6.48 (s, 1H), 1.68 (s, 18H), 1.58 (s, 18H). The tetradentate ligand compound 1, 1-(3-(3-(1H-pyrazol-1-yl)phenoxy)phenyl)-4-chloro-1H-pyrazole can be prepared by either of the following two synthetic methods: Method 1: The synthetic route and specific preparation steps are as follows:

[0149] Specifically, its preparation method includes the following steps: 1) Synthesis of 1-[3-(3-bromophenoxy)phenyl]-1H-pyrazole: 3-bromophenol (1.73 g, 10.0 mmol, 1.0 equivalent), 1-(3-bromophenyl)-1H-pyrazole (3.35 g, 15.0 mmol, 1.5 equivalent), cuprous iodide (0.10 mg, 0.5 mmol, 0.05 equivalent), pyridinecarboxylic acid (0.12 mg, 1.0 mmol, 0.1 equivalent), and potassium phosphate (2.12 g, 10.0 mmol, 1.0 equivalent) were sequentially added to a dry three-necked flask equipped with a magnetic stirrer. The flask was evacuated and backfilled with nitrogen; this process was repeated three times. Dimethyl sulfoxide (20 mL) was added under a nitrogen atmosphere, and the reaction system was heated in a 100 °C oil bath with stirring (heating rate of 5 °C / min during the heating phase). The reaction was monitored for completion by thin-layer chromatography after 48 hours. The resulting mixture was cooled to room temperature, diluted with a large amount of ethyl acetate, filtered through a diatomaceous earth filter, and washed with additional ethyl acetate. The filtrate was washed three times with brine, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and purified by silica gel column chromatography (eluent: petroleum ether / ethyl acetate volume ratio = 8:1~6:1) to give 1.73 g of 1-[3-(3-bromophenoxy)phenyl]-1H-pyrazole white solid, yield 55%.

[0150] 2) Synthesis of Compound 1: 1-[3-(3-bromophenoxy)phenyl]-1H-pyrazole (1.58 g, 5.0 mmol, 1.0 equivalent), 4-chloropyrazole (0.51 g, 5.0 mmol, 1.0 equivalent), cuprous iodide (0.10 g, 0.5 mmol, 0.1 equivalent), L-proline (0.12 g, 1.0 mmol, 0.2 equivalent), and potassium carbonate (1.38 g, 10.0 mmol, 2.0 equivalent) were dissolved in dimethyl sulfoxide (20 mL). The mixture was heated to 90 °C at a rate of 5 °C / min under a nitrogen atmosphere and stirred at 90 °C for 48 hours, followed by cooling to room temperature. The reaction mixture was diluted with ethyl acetate, filtered through diatomaceous earth, washed three times with water, dried over sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using n-hexane / ethyl acetate (volume ratio 5:1 to 3:1) as eluent to give 0.64 g of white solid product (compound 1), yield 38%.

[0151] Method 2: The synthesis route and specific steps are as follows:

[0152] 1) Compound A (4-chloropyrazole, 15 mmol), compound C (Cs₂CO₃, 15 mmol), and compound D (CuO, 1 mmol) were added to a sealed tube. The tube was purged three times, and then argon or nitrogen was introduced. 10-50 mL of DMF was added, and the tube was stirred while purging or purging. Argon or nitrogen was introduced again, and finally compound B (3-bromophenol, 10 mmol) was added. The temperature was increased to 110 °C at a rate of 5 °C / min and reacted at 110 °C for 24 hours. After the reaction was completed, the mixture was quenched, extracted with DCM, washed with brine, and evaporated to dryness under reduced pressure. Column chromatography was performed using a mixture of petroleum ether and ethyl acetate in a volume ratio of 6:1 as the eluent to obtain a colorless solid (compound E, 3-(4-chloropyrazole-1-yl)phenol) in 75% yield.

[0153]

[0154] 2) Compound E (3-(4-chloropyrazole-1-yl)phenol, 10 mmol), compound F (1-(3-bromophenyl)-1H-pyrazole, 11 mmol), compound G (2-pyridinecarboxylic acid, 12 mmol), compound H (potassium phosphate, 30 mmol), and compound J (cuprous iodide, 4 mmol) were added to a sealed tube, the gas was purged three times, argon or nitrogen was introduced, and then 10-50 mL of DMSO was added. The mixture was stirred and purged or purged, and then argon or nitrogen was introduced again. The temperature was increased to 140 °C at a rate of 5 °C / min and reacted at 140 °C for 24 hours. After the reaction was completed, the mixture was quenched, extracted with DCM, washed with brine, and dried under reduced pressure. Column chromatography was performed using a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 20:1 as the eluent to obtain a white granular solid (compound 1) with a yield of 18%.

[0155] Compound 2 can be a commercially available product or can be prepared in-house. Specifically, it can be prepared by a method including the following steps, sequentially yielding a brominated intermediate, a brominated MR skeleton intermediate, and the final compound 2:

[0156] 1,4-Dibromo-2,6-difluorobenzene (18 mmol) and 3,6-di-tert-butylcarbazole (36–54 mmol) were added to a reaction flask, followed by t-BuOK (54 mmol). The mixture was stirred at 140 °C for 24 h under nitrogen protection using 50 mL of DMF as solvent. After the reaction was complete, the mixture was cooled to room temperature, quenched with water, extracted with ethyl acetate, and rotary evaporated. The crude product was purified by silica gel column chromatography to obtain a brominated intermediate. The obtained brominated intermediate was then added to 3.4 mL of n-BuLi n-hexane solution (2.5 mol / L) at -78 °C, and the temperature was increased to 50 °C at a rate of 5 °C / min. Subsequently, 2–4 mL of BBr3 was added at -30 °C, and the temperature was increased to room temperature at a rate of 5 °C / min. Then, 1–3 mL of DIPEA was added, and the temperature was increased from room temperature to 130 °C at a rate of 5 °C / min. After the reaction was completed and cooled to room temperature, the solution was quenched with water, extracted with dichloromethane, and rotary evaporated. The crude product was purified by column chromatography to obtain a bromine-containing MR-TADF framework intermediate related to DtBuCzB. The obtained bromine-containing MR framework intermediate was added to a reaction flask with pinacol diboronic acid ester (B2pin2, 10 mmol), Pd(dppf)Cl2 (0.1 mmol) and KOAc (30–50 mmol), and reacted at 90 °C for 24 h under nitrogen protection with 10–50 mL of 1,4-dioxane as solvent (heating rate 5 °C / min during the heating phase). After the reaction was completed and cooled to room temperature, the reaction solution was filtered through diatomaceous earth and the filter cake was washed with ethyl acetate. The solvent was then collected and rotary evaporated to obtain the crude product, which was purified by silica gel column chromatography to obtain the bis-Bpin borate ester derivative (compound 2).

[0157] This embodiment also discloses an electroluminescent device, which is an organic light-emitting diode (OLED), comprising the thermally activated delayed fluorescence material prepared in this embodiment. A schematic diagram of the organic light-emitting diode structure is shown below. Figure 16 As shown in Figure a, the schematic diagram of the material energy levels is as follows: Figure 16 As shown in Figure b, specifically, The electroluminescent device includes: ITO glass (containing a glass body approximately 1 mm thick and an indium tin oxide layer), with the indium tin oxide layer serving as the anode (ITO, thickness 120~180 mm). nm); 1,4,5,8,9,11-hexaazatriphenylhexacarbonitrile (HATCN) was used as the hole injection layer; N4,N4,N4',N4'-tetra([1,1'-biphenyl]-4-yl)-[1,1'-biphenyl]-4,4'-diamine (TBBD) and N-([1,1'-biphenyl]-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirodi[fluorene]-2-amine (o-SFAF) were used as the hole transport layer; 9,9'-[5-(triphenylsilyl)-1,3-phenylene]bis-9H-carbazole (SiCzCz) was used as the hole transport and electron blocking layer; an excimer complex formed from SiCzCz and SiTrzCz2TADF materials was used. As the host material for the light-emitting layer (EML), the EML is doped with DtBuCzB-Pt prepared in this embodiment. The host material of the EML is an exciplex formed by SiCzCz and SiTrzCz2. The 9,9'-(6-(3-(triphenylsilyl)phenyl)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole) (SiTrzCz2) layer has both electron transport and hole blocking functions. The 1-[4-(10-([1,1'-biphenyl]-4-yl)anthracene-9-yl)phenyl]-2-ethyl-1H-benzi[d]imidazole (ANT-BIZ) layer is used as the electron transport layer. The 8-hydroxyquinoline lithium (Liq) layer is used as the electron injection layer (thickness of 1~2 nm). Metallic Al is used as the cathode (thickness of 100~150 nm). The molecular structures of the carrier injection and transport layers used in the device are as follows: Figure 16 As shown in Figure b. To optimize the performance of the organic light-emitting diode, a gradient experiment was conducted to increase the doping concentration of DtBuCzB-Pt in the light-emitting layer from 1.0 wt.% to 2.5 wt.%.

[0158] The fabrication steps of an organic light-emitting diode include: sequentially depositing the following on a pre-cleaned ITO glass substrate: Figure 16 The layers shown in Figure a (see Figure a for layer thickness details) Figure 16 (As shown in Figure b), the deposition process occurs at less than 10 -6 The process is carried out under Torr pressure. During OLED fabrication, the thermal evaporation rates of organic materials, LiF, and Al are 0.5–2 Å s⁻¹, respectively. -1 0.1~0.2 Ås -1 and 1~5 Å s -1For each device, four pixel blocks with the same device configuration were fabricated in a batch, with the deposited Al cathode overlapping the pre-coated ITO anode to form an effective area of ​​3 mm × 3 mm for each pixel block.

[0159] Example 2 This embodiment discloses a thermally activated delayed fluorescence material, the preparation method of which includes the following steps: (I) Synthesis (Suzuki coupling) of the MR-TADF skeleton derivative (compound 6, diphenylamine boron nitrogen-linked phenylpyrazole tetradentate ligand) connected with the tetradentate ligand, comprising the following steps:

[0160] Compound 1 (10 mmol) and compound 5 (5–20 mmol) were added to a dry reaction flask. 30–50 mL of toluene and water (3:1 v / v) were added as a mixed solvent. K₂CO₃ (50 mmol) was added, along with Pd₂(dba)₃ (0.1–0.2 mmol) and the ligand 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl (SPhos, 0.2–0.4 mmol). The reaction system was evacuated and backfilled with nitrogen three times. The reaction was then carried out under nitrogen protection at 100 °C with stirring for 24 h (the reaction progress could be monitored by TLC or sampling). After the reaction was complete, the mixture was cooled to room temperature. The reaction solution was diluted with ethyl acetate, filtered through diatomaceous earth to remove inorganic salts and catalyst residue, and the filter cake was washed with ethyl acetate. The combined filtrates were washed with water (and saturated brine if necessary). The organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (elution system can refer to petroleum ether / ethyl acetate gradient) to give compound 6 (6 mmol, 4.3 g, yield 60%).

[0161] The proton and carbon spectra of compound 6 are shown below. Figures 4-5 As shown: 1 H NMR (500 MHz, CDCl3) δ 8.96 (dd, J = 7.8, 1.7 Hz, 2H), 7.90 (d, J =2.5 Hz, 1H), 7.73 (t, J = 7.8 Hz, 5H), 7.68 (s, 1H), 7.66 – 7.59 (m, 2H), 7.55 (s, 1H), 7.50 – 7.27 (m, 14H), 6.94 (t, J = 7.5 Hz, 2H), 6.78 (d, J= 7.8 Hz, 2H), 6.47 (t, J = 2.2 Hz, 1H), 6.27 (s, 2H). 13 C NMR (126 MHz, CDCl3) δ 157.97, 157.76, 147.84, 147.66, 142.30,141.46, 139.63, 135.16, 131.33, 131.09, 130.85, 130.78, 130.66, 128.92,126.96, 126.13, 123.91, 120.20, 117.22, 116.99, 116.86, 114.32, 114.10,110.36, 110.09, 108.04, 102.77. (II) Synthesis of intramolecular sensitized platinum complex DABNA-Pt (complex 7) (Pt(II) metallization), including the following steps:

[0162] Compound 6 (5 mmol) and K₂PtCl₄ (5–10 mmol) were added to 50–300 mL of glacial acetic acid (AcOH) and stirred and heated to 110 °C for 48 h under a nitrogen atmosphere. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was slowly poured into water. The organic product was extracted with dichloromethane or ethyl acetate. The combined organic phases were washed with water (or saturated brine), dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluting with a petroleum ether / dichloromethane solvent system at a volume ratio of 5:1–2:1), or optionally by recrystallization to obtain the target intramolecular sensitized platinum complex (complex 7, DABNA-Pt, 1.5 mmol, 1.37 g, yield 30%).

[0163] A schematic diagram of the single-crystal structure of the intramolecular sensitized platinum complex DABNA-Pt (complex 7, also known as: diphenylamine boron nitrogen-linked platinum complex) is shown below. Figure 6 As shown, the proton spectrum and carbon spectrum are respectively as follows: Figures 7-8 As shown: 1 H NMR (500 MHz, CDCl3) δ 8.98 (dd, J = 7.8, 1.6 Hz, 2H), 8.04 (d, J =2.7 Hz, 1H), 7.83 – 7.76 (m, 5H), 7.69 (t, J= 7.5 Hz, 2H), 7.59 (d, J = 3.6Hz, 2H), 7.48 (d, J = 7.0 Hz, 5H), 7.32 (t, J = 7.3 Hz, 2H), 7.16 (dd, J = 11.3, 7.9 Hz, 3H), 7.04 (t, J = 6.6 Hz, 3H), 6.93 (d, J = 7.6 Hz, 1H), 6.81 (d, J =8.5 Hz, 2H), 6.63 (t, J = 2.4 Hz, 1H), 6.29 (s, 2H). 13 C NMR (126 MHz, CDCl3) δ 152.74, 147.78, 142.33, 139.64, 137.72,135.22, 134.29, 131.58, 131.44, 131.23, 130.74, 129.42, 129.01, 126.58,125.46, 124.58, 124.45, 124.34, 123.29, 123.15, 120.40, 117.29, 114.65,107.36, 105.45, 102.71. The tetradentate ligand 1-(3-(3-(1H-pyrazol-1-yl)phenoxy)phenyl)-4-chloro-1H-pyrazole (compound 1) can be prepared by either of the two synthetic methods described in Example 1.

[0164] Compound 5 can be a commercially available product or can be prepared in-house, specifically by a method including the following steps:

[0165] Under nitrogen protection, bis(1,5-cyclooctadiene)dimethoxyiridium ([Ir(COD)(OCH3)]2, 39.8 mg, 0.06 mmol), 4,4'-di-tert-butyl-2,2'-dipyridine (dtbpy, 32.2 mg, 0.12 mmol), and pinacol diboronate (compound 9, 1.57 g, 6.2 mmol) were sequentially added to an ultra-dry THF solution containing compound 8 (2.50 g, 6.0 mmol). The system was evacuated and backfilled with nitrogen three times, then heated to approximately 70 °C and stirred under reflux for 24 h. After the reaction was complete, the mixture was extracted with dichloromethane and deionized water. The combined organic phases were dried over anhydrous Na2SO4, filtered, and the solvent was removed by rotary evaporation under reduced pressure. The crude product was further purified by column chromatography to give a yellow solid compound 5 (DABNA-Bpin, 2.77 g, 85% yield).

[0166] This embodiment also discloses a light-emitting device, including the thermally activated delayed fluorescence material prepared in this embodiment. Example 3 This embodiment discloses a thermally activated delayed fluorescence material, which is a palladium complex (DtBuCzB-Pd) with a tert-butylcarbazole boron nitrogen backbone. Its preparation method includes the following steps: (I) The synthesis of the intramolecular sensitized palladium complex DtBuCzB-Pd (complex 12) includes the following steps:

[0167] Compound 10 (10 mmol) and compound 2 (DtBuCzB-Bpin, 5–20 mmol) were added to a reaction flask. 30–50 mL of toluene and water (3:1, volume ratio) was used as a mixed solvent. Potassium carbonate (K₂CO₃) (50 mmol) was added as a base, and tetrakis(triphenylphosphine)palladium [Pd(PPh₃)₄] (0.1–0.2 mmol) was added as a catalyst. The reaction was stirred at 100 °C for 24 h under a nitrogen atmosphere to induce a Suzuki coupling reaction. After the reaction was completed, the mixture was cooled to room temperature, extracted with ethyl acetate, and rotary evaporated to obtain the crude product. The crude product was then purified by silica gel column chromatography to obtain the target coupling intermediate (compound 11, 7 mmol, 6.7 g, 70%). Subsequently, the intermediate compound 11 (5 mmol) was added to 50–300 mL of glacial acetic acid (HOAc), and palladium acetate [Pd(OAc)2] (5–10 mmol) was added. The mixture was stirred at 110 °C for 36 h under a nitrogen atmosphere to allow palladium metallization of ligand compound 11. After the reaction was completed, the mixture was cooled to room temperature and further purified by column chromatography (using petroleum ether / dichloromethane at a volume ratio of 5:1–2:1 as the eluent, or by recrystallization) to obtain the target product: intramolecular sensitized palladium complex (complex 12, DtBuCzB-Pd, 1.5 mmol, 1.6 g, yield 15%).

[0168] The proton and carbon spectra of compound 11 (tert-butylcarbazole boron nitrogen-linked phenylpyridine tetradentate ligand) are shown below. Figures 9-10 As shown: 1 H NMR (500 MHz, CDCl3) δ 9.05 – 8.95 (m, 2H), 8.81 (d, J = 5.0 Hz, 1H), 8.64 (d, J = 4.7 Hz, 1H), 8.41 (d, J = 1.4 Hz, 2H), 8.35 (s, 2H), 8.26 (d, J = 8.8 Hz, 2H), 8.22 (d, J = 1.7 Hz, 2H), 8.03 (s, 1H), 7.92 (s, 1H), 7.87(d, J = 7.8 Hz, 1H), 7.78 (d, J = 1.9 Hz, 1H), 7.75 (d, J = 7.9 Hz, 1H), 7.68 (d, J= 4.8 Hz, 2H), 7.63 (dd, J = 8.7, 1.8 Hz, 2H), 7.60 – 7.53 (m, 2H), 7.47(t, J = 7.9 Hz, 1H), 7.19 (td, J = 7.8, 2.4 Hz, 3H), 1.66 (s, 18H), 1.53 (s, 18H). 13 C NMR (151 MHz, CDCl3) δ 158.07, 157.85, 157.67, 156.79, 150.38,150.06, 149.76, 145.58, 144.83, 144.74, 142.86, 141.72, 141.65, 141.52,138.23, 136.90, 130.41, 130.30, 129.79, 127.25, 124.69, 123.75, 122.50,122.26, 122.14, 121.23, 120.97, 120.80, 119.77, 119.69, 119.38, 118.08, 117.74, 117.52, 114.22, 106.59, 77.37, 77.16, 76.95, 35.28, 34.93, 32.29, 31.94. The proton and carbon spectra of the intramolecular sensitized palladium complex DtBuCzB-Pd (complex 12, also known as: tert-butylcarbazole boron nitrogen-linked palladium complex) are shown below. Figures 11-12 As shown: 1 H NMR (400 MHz, CDCl3) δ 8.99 (s, 2H), 8.72 (d, J = 5.5 Hz, 1H), 8.60(s, 1H), 8.51 (s, 2H), 8.41 (s, 2H), 8.39 – 8.31 (m, 3H), 8.21 (s, 2H), 7.82– 7.72 (m, 4H), 7.66 (d, J = 8.8 Hz, 2H), 7.44 – 7.38 (m, 2H), 7.31 (d, J = 7.7Hz, 1H), 7.21 (s, 1H), 7.17 (d, J= 7.1 Hz, 2H), 1.68 (s, 18H), 1.54 (s, 18H). 13 C NMR (126 MHz, CD2Cl2) δ 152.18, 149.21, 146.30, 145.34, 142.11,138.66, 130.36, 127.72, 126.05, 125.15, 124.22, 122.64, 122.12, 121.62,118.27, 118.13, 114.62, 107.02, 54.43, 54.22, 54.00, 53.78, 53.57, 35.65,35.28, 32.48, 32.11. Compound 2 may be a commercially available product or may be prepared by the preparation method described in Example 1.

[0169] Tetradentate ligand compound 10 can be prepared by the following method: (Aromatic oxygen-linked ppy-Br intermediate) (Aromatic ring-Bpin borate intermediate)

[0170] First, 2-[3-(3-bromophenoxy)phenyl]pyridine was synthesized. 3-bromophenol (10 mmol) and 2-(3-bromophenyl)pyridine (15 mmol) were added to a dry reaction flask, along with K3PO4 (30 mmol), pyridinecarboxylic acid (2 mmol), and CuI (1 mmol). Using 10–30 mL of DMSO as solvent, the mixture was stirred at 100 °C for 24 h under nitrogen protection. After the reaction was complete, the mixture was cooled to room temperature, filtered through diatomaceous earth, and extracted with ethyl acetate and water using a separatory funnel. The crude product was obtained by rotary evaporation of the organic solvent and then purified by silica gel column chromatography to yield the aryloxy-linked ppy-Br intermediate: 2-[3-(3-bromophenoxy)phenyl]pyridine (5 mmol, 1.6 g, 50%).

[0171] The obtained aryloxy-linked ppy-Br intermediate (5 mmol) and B2pin2 (5–10 mmol) were added to a reaction flask, along with Pd(dppf)Cl2 (0.05 mmol) and KOAc (15 mmol). Using 10–30 mL of 1,4-dioxane as solvent, the mixture was stirred at 90 °C for 24 h under nitrogen protection. After the reaction was complete and cooled to room temperature, the reaction solution was filtered through diatomaceous earth, and the filter cake was washed with ethyl acetate. The solvent was then collected and rotary evaporated to obtain the crude product. The crude product was purified by silica gel column chromatography to obtain the aryl-Bpin borate intermediate (3.5 mmol, 1.3 g, 70%).

[0172] The obtained aromatic ring-Bpin borate intermediate (3.5 mmol) and 2,4-dibromopyridine (3.5–7 mmol) were added to a reaction flask, along with Pd(PPh3)4 (0.04 mmol) and K2CO3 (12 mmol). A mixed solvent of 10–30 mL toluene and water (3:1 v / v) was used, and the mixture was stirred at 100 °C for 24 h under nitrogen protection. After the reaction was complete, the mixture was cooled to room temperature, extracted with ethyl acetate, and rotary evaporated to obtain the crude product. The crude product was then purified by silica gel column chromatography to give the target product compound 10 (2.1 mmol, 0.85 g, yield 60%).

[0173] Test case This experimental example demonstrates the performance testing of the thermally activated delayed fluorescence materials and light-emitting devices of each embodiment, specifically including: (1) The photophysical data, electrochemical and thermal stability test results of the complex DtBuCzB-Pt prepared in Example 1 are summarized in Table 1 below: Table 1

[0174] a Measured in toluene solution at room temperature. b Measurements were taken at room temperature in a 1 wt% doped 9,9'-(1,3-phenyl)bis-9-hydro-carbazole thin film (mCP film). c The S1 energy level was estimated based on the maximum fluorescence values ​​in toluene solution and 9,9'-(1,3-phenyl)bis-9-hydro-carbazole films. d The T1 energy level is estimated based on the maximum phosphorescence value in toluene solution and mCP thin film at 77 K. e E ST = E S1 – E T1 . f HOMO level determined by cyclic voltammetry in dichloromethane.g The LUMO level is calculated from the HOMO level and the optical band gap.

[0175] The UV-Vis absorption and emission spectra of the complexes DtBuCzB-Pt, DABNA-Pt, DtBuCzB-Pd and related substances prepared in Examples 1-3 are as follows: Figures 13-15 As shown: Figure 13 Figure a shows the absorption and emission spectra of the following substances, and Figure b shows the absorption and emission spectra of DtBuCzB-Pt: (Emission spectrum); (Absorption spectrum); Figure 14 Figure a shows the absorption and emission spectra of the following molecule, and Figure b shows the absorption and emission spectra of DABNA-Pt: (Emission spectrum); (Absorption spectrum); Figure 15 Figure a shows the absorption and emission spectra of the following molecule, and Figure b shows the absorption and emission spectra of DtBuCzB-Pd: (Emission spectrum); (Absorption spectrum).

[0176] (2) Reverse intersystem crossing rate (k) of the platinum complex (DtBuCzB-Pt) in Example 1 RISC The efficiency was significantly increased to 8.14 × 10⁻⁶. 5 s -1 The method includes the following steps: calculating k RISC The photoluminescence quantum yield (Φ) of the material is obtained by integrating the sphere. PL ) and the lifetime (τ) of instantaneous fluorescence and delayed fluorescence of the material measured by transient fluorescence spectroscopy. p , τ d Based on a three-level (ground state S0, lowest singlet state S1, and lowest triplet state T1) dynamic model, these experimental parameters were substituted into the core formula k. RISC = (k p k d Φ d ) / (k ISC Φ p It was calculated.

[0177]

[0178] (3) The performance test results of the electroluminescent device (organic light-emitting diode) prepared in Example 1 are as follows: Figure 17See Table 2, where the EL spectrum of the device was measured in the normal orientation using an Ocean Optics USB 2000. JVL curves were investigated using a dual-channel Keithley 2614B source measurement unit and a PIN-25D silicon photodiode.

[0179] Figure 17 In the figure, D1 to D4 represent the device performance of electroluminescent devices with DtBuCzB-Pt complex doping concentrations of 1.0 wt.%, 1.5 wt.%, 2.0 wt.%, and 2.5 wt.%, respectively. Figure A shows the electroluminescence (EL) spectra of the D1-D4 series electroluminescent devices; Figure b shows the current density-voltage-luminance (JVL) curves of the D1-D4 series electroluminescent devices; Figure c shows the external quantum efficiency-luminance (EQE-L) curves of the D1-D4 series electroluminescent devices; and Figure d shows the current efficiency-luminance-power efficiency (CE-L-PE) curves of the D1-D4 series electroluminescent devices. The performance test results of the electroluminescent devices are summarized in Table 2 below. Table 2 Summary of the performance of blue OLED devices based on DtBuCzB-Pt

[0180] a At 1000 cd m - ²Emission peak wavelength of electroluminescence (EL) spectrum at brightness. b At 1000 cd m - ²Full width at half maximum (FWHM) of electroluminescence (EL) spectrum at brightness. c Maximum external quantum efficiency (EQE) and at 1000 cd m - ² External quantum efficiency value at brightness.

[0181] This invention designs and synthesizes a class of short-wavelength emitting metal complexes (metal: platinum or palladium) bonded to the periphery of an MR-TADF framework. These materials integrate the metal complexes into a multiple resonance thermally activated delayed fluorescence (MR-TADF) framework. This design achieves efficient utilization and directional transport of triplet excitons of the metal complexes through intramolecular energy transfer, transforming them into singlet states of the MR-TADF component. The structure of these metal complexes bonded to the periphery of the MR-TADF framework was confirmed by NMR spectroscopy and single-crystal X-ray diffraction. UV-Vis absorption and fluorescence emission spectroscopy tests show that the emission wavelengths of the metal complexes overlap with the absorption wavelengths of the MR-TADF component, allowing energy to be transferred to the emission state of the MR-TADF component in the excited state via a platinum (II) or palladium (II) medium. These ultimately obtained thermally activated delayed fluorescence materials (hybrid molecules) exhibit good potential, with the reverse intersystem crossing rate (k) of the platinum complex with a di-tert-butylcarbazole boron framework (DtBuCzB-Pt) being particularly high. RISC The efficiency was significantly increased to 8.14 × 10⁻⁶. 5 s -1 Meanwhile, its emission wavelength and full width at half maximum (FWHM) remain almost unchanged compared to the parent core DtBuCzB. OLED devices fabricated based on this coupled emitter DtBuCzB-Pt achieve a maximum external quantum efficiency (EQE) as high as 22.45%. max It is worth noting that the device exhibits almost no efficiency roll-off at a brightness of 1000 cd / m².

[0182] In summary, the coupling of Pt(II) phosphorescent complexes or Pd(II) phosphorescent complexes with the MR-TADF molecule DtBuCzB in this invention results in a thermally activated delayed fluorescence material that not only enhances the reverse intersystem crossing rate (kΩ) of its hybrid molecules through intramolecular energy transfer, but also... RISC Furthermore, it can effectively reduce its roll-off rate. A representative platinum-based complex (DtBuCzB-Pt) based on a di-tert-butylcarbazole boron MR-TADF framework was designed and synthesized. Its photophysical and electroluminescent properties were measured, and OLEDs were fabricated using thermally activated delayed fluorescence materials as emitters. Moreover, the introduction of metal phosphorescent complexes overcomes the limitations of the thermal activation mechanism, opening up a new intramolecular pathway for achieving triplet-singlet exciton conversion. Its synergistic effect significantly improves the utilization efficiency of triplet excitons, especially under high-brightness conditions.

[0183] Unless otherwise specified, the term "about" in this invention actually means that the allowable error is within ±2%, for example, about 100 is actually 100 ± 2% × 100. The terms "room temperature" and "room temperature" in this invention, unless otherwise specified, are approximately 20~30℃. The phrase "between..." in this invention includes the number itself; for example, "between 2 and 3" includes the endpoints 2 and 3.

[0184] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A thermally activated delayed fluorescence material, characterized in that, Includes at least one of the complexes shown in Formula I or Formula II: ； Unit A comprises a conjugated fused structure containing a plurality of saturated or unsaturated multi-membered rings, each of the multi-membered rings being independently selected from five-membered or six-membered rings, wherein at least two of the multi-membered rings are heterocycles containing N and B, and at least three of the multi-membered rings are aromatic rings; Each occurrence of M is independently selected from either Pt(II) or Pd(II); Each occurrence of R' is independently selected from hydrogen, deuterium, hydroxyl, mercapto, halogen group, cyano, acyl, substituted or unsubstituted amino, substituted or unsubstituted hydrocarbon, substituted or unsubstituted alkoxy, substituted or unsubstituted alkylthio, substituted or unsubstituted silyl, substituted or unsubstituted aryl. m is an integer, and each occurrence of m is independently selected from 1 to 10.

2. The thermally activated delayed fluorescence material according to claim 1, characterized in that, When R' is a substituted amino group, a substituted hydrocarbon group, a substituted alkoxy group, a substituted alkathio group, a substituted silyl group, or a substituted aryl group, the substituent group is selected from hydroxyl, mercapto, halogen group, cyano, ester group, amide group, amino, C1~C1. 10 Alkyl, C1~C 10 alkenyl, C1~C 10 alkynyl group, C1~C 10 alkoxy groups, C1~C 10 Silyl groups, C1~C 10 The alkylthio, phenyl, naphthyl, pyridyl, furanyl, or indoleyl groups; And / or, the Formula I complex includes at least one of a meridional structure or a planar structure, and / or, the Formula II complex includes at least one of a meridional structure or a planar structure; And / or, the complex of formula I is: ； And / or, the complex of formula II is: 。 3. The thermally activated delayed fluorescence material according to claim 1, characterized in that, The A unit includes at least one of the following structures: Each time the group R appears, it is independently selected from hydrogen, deuterium, hydroxyl, mercapto, halogen group, cyano, acyl, substituted or unsubstituted amino, substituted or unsubstituted hydrocarbon, substituted or unsubstituted alkoxy, substituted or unsubstituted alkylthio, substituted or unsubstituted silyl, substituted or unsubstituted aryl. The r is an integer, and each occurrence of r is independently selected from 0 to 10; Each occurrence of the group L is independently selected from O, S, N, and -(CH2). n -or At least one of the following, where n is an integer, and each occurrence of n is independently selected from 1 to 10; Preferably, when the group R is a substituted amino group, a substituted hydrocarbon group, a substituted alkoxy group, a substituted alkylthio group, a substituted silyl group, or a substituted aryl group, the substituted group is selected from hydroxyl, mercapto, halogen group, cyano, ester group, amide group, amino, C1~C1. 10 Alkyl, C1~C 10 alkenyl, C1~C 10 alkynyl group, C1~C 10 alkoxy groups, C1~C 10 Silyl groups, C1~C 10 The alkylthio, phenyl, naphthyl, pyridyl, furanyl, or indoleyl groups.

4. The thermally activated delayed fluorescence material according to claim 1, characterized in that, The complex of formula I includes at least one of the following complexes: 。 5. The thermally activated delayed fluorescence material according to claim 1, characterized in that, The complex of formula II includes at least one of the following complexes: 。 6. A method for preparing the thermally activated delayed fluorescence material according to claim 1, characterized in that, Includes the following steps: S2, the raw materials containing the metal M precursor and ligand are mixed and heated to obtain the thermally activated delayed fluorescence material, wherein the ligand includes at least one of the complexes shown in Formula I' or Formula II': 。 7. The method for preparing the thermally activated delayed fluorescence material according to claim 6, characterized in that, The heating temperature is 80~200℃; and / or the heating reaction time is 24~100h; and / or the molar ratio of the metal M precursor to the ligand is (1~10):

1.

8. The method for preparing the thermally activated delayed fluorescence material according to claim 6, characterized in that, The preparation method further includes preparing the ligand, specifically including: S1, the raw materials containing compound A and compound B are mixed and subjected to a Suzuki coupling reaction to obtain the ligand, wherein compound B includes at least one of the compounds shown in formula B-1 or formula B-2: Each time X appears, it is independently selected from F, Cl, Br, or I.

9. The method for preparing the thermally activated delayed fluorescence material according to claim 8, characterized in that, In step S1, the raw materials for preparation include catalyst I and an alkaline substance; Preferably, the catalyst I comprises at least one of tris(dibenzylacetone)palladium, tetra(triphenylphosphine)palladium, bis(benzylacetone)palladium, palladium acetate, bis(triphenylphosphine)palladium dichloride, or 1,1'-bis(diphenylphosphine)ferrocene palladium dichloride; Preferably, the alkaline substance includes at least one of potassium carbonate, sodium carbonate, lithium carbonate, cesium carbonate, potassium acetate, sodium acetate, lithium acetate, cesium acetate, potassium tert-butoxide, sodium tert-butoxide, lithium tert-butoxide, cesium tert-butoxide, triethylamine, trimethylamine, DBU, TBD, MTBD, or diisopropylethylenediamine.

10. A light-emitting device, characterized in that, Includes the thermally activated delayed fluorescence material according to any one of claims 1 to 5 or the thermally activated delayed fluorescence material prepared by the preparation method according to any one of claims 6 to 9.

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