Phosphine-containing TADF compound as well as preparation method and application thereof

Abstract

The invention relates to the technical field of organic electroluminescence, in particular to a phosphine-containing TADF compound and a preparation method and application thereof, and the general formula structure of the phosphine-containing TADF compound is shown in the specification. Ar is phenyl, deuterated phenyl, biphenyl, partially deuterated biphenyl, terphenyl, partially deuterated terphenyl, naphthyl, 9-phenyl anthryl, pyrenyl, phenanthryl, phenyl, benzanthryl, dibenzofuranyl, dibenzothienyl, 9, 9-dimethyl fluorenyl, 9, 9-dimethylfluorenyl, 9, 9-dimethylfluorenyl, 9, 9-dimethylfluorenyl, 9, 9-dimethylfluorenyl, 9, 9-dimethylfluorenyl, 9, 9-dimethylfluorenyl, 9, 9-dimethylfluorenyl, 9, 9 the structural formula is selected from any one of 9-phenyl fluorenyl, 9-diphenyl fluorenyl, 9-phenyl dibenzo carbazolyl and partially deuterated 9-phenyl dibenzo carbazolyl, or partially deuterated 9-phenyl dibenzo carbazolyl. The phosphine-containing TADF compound is high in molecular rigidity, has the advantages of high glass transition temperature and good thermal stability, is high in fluorescence quantum efficiency, and remarkably improves the luminous efficiency of a device. The organic electroluminescent element using the compound as a host luminescent material has higher luminous efficiency and longer service life.

Description

Technical Field

[0001] This invention relates to a phosphine-containing TADF compound, its preparation method and application, belonging to the field of organic electroluminescence technology. Background Technology

[0002] The core advantage of Organic Light Emitting Diodes (OLEDs) is their self-emissive nature, eliminating the need for a backlight module and enabling pixel-level independent control. They possess advantages such as high resolution, high brightness, wide viewing angle, wide color gamut, and low power consumption. OLED development has progressed from fluorescent materials and phosphorescent materials to thermally activated delayed fluorescence (TADF) materials. The unique donor-acceptor structure of TADF materials results in minimal spatial overlap between the highest occupied orbitals and the lowest unoccupied orbitals. This structural advantage leads to a very small energy level difference between the singlet and triplet excited states. Due to this small energy level difference, the exciton in the triplet state absorbs thermal energy from the environment, causing it to backflip back to the singlet state. The exciton then radiatively transitions from the singlet state back to the ground state, emitting light. This light emitted from the singlet state is delayed fluorescence. Thanks to this characteristic, TADF materials exhibit high luminous efficiency.

[0003] Currently, OLED devices generally suffer from low luminous efficiency and short lifespan. Therefore, developing OLED devices with high luminous efficiency and long lifespan remains a hot topic. Boron-containing aromatic compounds are a type of TADF material with a theoretical fluorescence quantum efficiency approaching 100%, effectively solving the luminous efficiency problem of OLED devices. These OLED devices also have the advantages of high vapor deposition decomposition temperature and high glass transition temperature, significantly improving device lifespan. Furthermore, devices fabricated from this material offer advantages such as low cost and tunable color. Therefore, for the current OLED industry, TADF materials are a new type of organic light-emitting material with enormous application prospects in organic light-emitting diodes, lighting, and displays. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a phosphine-containing TADF compound, its preparation method, and its applications. The phosphine-containing TADF compound exhibits high molecular rigidity, a high glass transition temperature, and good thermal stability. Furthermore, this type of compound demonstrates high fluorescence quantum efficiency, significantly improving the luminous efficiency of devices. Therefore, organic electroluminescent devices using the compound of this invention as the primary luminescent material possess higher luminous efficiency and a longer lifespan.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a phosphine-containing TADF compound, wherein the general formula structure of the phosphine-containing TADF compound is as follows: ; Ar is any one of phenyl, deuterated phenyl, biphenyl, partially deuterated biphenyl, terphenyl, partially deuterated terphenyl, naphthyl, 9-phenylanthrayl, pyrene, phenanthryl, thionyl, benzoanthrayl, dibenzofuranyl, dibenzothiophene, 9,9-dimethylfluorenyl, 9,9-diphenylfluorenyl, 9-phenyldibenzocarbazoyl, and partially deuterated 9-phenyldibenzocarbazoyl.

[0006] Furthermore, the Ar is selected from any one of the following group structures: .

[0007] Furthermore, the phosphine-containing TADF compound is selected from the following compound structures: .

[0008] This invention also discloses a method for preparing a phosphine-containing TADF compound, wherein the preparation method is as follows: ; Preparation of intermediate M: Intermediate L, intermediate G, potassium carbonate, water, tetra(triphenylphosphine)palladium, and tetrahydrofuran were added to a reactor, and the mixture was stirred and heated to carry out the reaction. After the reaction was completed, intermediate M was obtained by post-treatment and purification. Preparation of intermediate N: Aluminum trichloride and toluene were added to a reactor, and the temperature was controlled. A mixed solution of intermediate M, triethylamine and toluene was added dropwise. After the addition was complete, the temperature was maintained to carry out the reaction. After the reaction was completed, intermediate N was obtained. Preparation of phosphine-containing TADF compound: Intermediate N, Ar-B(OH)2, potassium carbonate, palladium acetate, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, water, and solvent were added to a reactor, stirred and heated to carry out the reaction. After the reaction was completed, the compound O was obtained by post-treatment purification. The compound O is a phosphine-containing TADF compound.

[0009] Furthermore, the preparation method of the intermediate G is as follows: ; Preparation of intermediate A: 1-bromo-2,5-dichloro-3-fluorobenzene, 4-tert-butylaniline, sodium tert-butoxide, (tris(dibenzylacetone))dipalladium(O), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl and toluene were added to a reactor and heated to carry out the reaction. After the reaction was completed, intermediate A was obtained by hydrolysis and post-treatment purification. Preparation of intermediate B: Methyl magnesium chloride solution and tetrahydrofuran were added to a reactor, and the temperature was controlled at ≤-5.0℃. Dimethyl phosphite was added dropwise. After the addition was completed, the temperature was maintained at -5.0~0℃ for reaction. After the reaction was completed, intermediate B was obtained by hydrolysis and post-treatment purification. The preparation of intermediate C involves adding intermediate B, m-bromoiodobenzene, triethylamine, tetra(triphenylphosphine)palladium, and dioxane to a reactor, and heating the reactor under stirring conditions. After the reaction is completed, intermediate C is obtained by post-treatment and purification. Preparation of intermediate D: Intermediate A, intermediate C, sodium tert-butoxide, (tris(dibenzylacetone))dipalladium(O), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl and toluene were added to a reactor and heated to carry out the reaction. After the reaction was completed, intermediate D was obtained by post-treatment and purification. Preparation of intermediate E: Intermediate B, m-bromophenol, triethylamine, tetra(triphenylphosphine)palladium, and dioxane were added to a reactor and heated under stirring conditions. After the reaction was completed, intermediate E was obtained by post-treatment and purification. Preparation of intermediate F: Intermediate D, intermediate E, potassium carbonate and DMF were added to the reactor, stirred and heated to carry out the reaction. After the reaction was completed, intermediate F was obtained by hydrolysis and post-treatment purification. Preparation of intermediate G: Intermediate F, pinacol diborate, potassium acetate, palladium acetate, 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl, and xylene were added to a reactor, stirred and heated to carry out the reaction. After the reaction was completed, intermediate G was obtained by hydrolysis and post-treatment purification.

[0010] Furthermore, the preparation method of the intermediate L is as follows: ; Preparation of intermediate H: 5-bromo-2-iodophenylacetic acid, concentrated sulfuric acid, and methanol were added to a reactor, stirred and heated to carry out the reaction. After the reaction was completed, intermediate H was obtained by hydrolysis and post-treatment purification. Preparation of intermediate I: p-chlorophenylboronic acid, intermediate H, potassium carbonate, water, tetra(triphenylphosphine)palladium, and tetrahydrofuran were added to a reactor, stirred and heated to carry out the reaction. After the reaction was completed, intermediate I was obtained by post-treatment and purification. Preparation of intermediate J: Intermediate I and tetrahydrofuran were added to the reactor. Under controlled temperature conditions, lithium bis(trimethylsilyl)amino was added dropwise. After the addition was completed, the temperature was controlled at 10-20℃ and the reaction was maintained. Iodomethane was added dropwise. After the addition was completed, the temperature was controlled at 10-20℃ and the reaction was carried out. After the reaction was completed, intermediate J was obtained by hydrolysis and post-treatment purification. Preparation of intermediate K: Intermediate J and tetrahydrofuran were added to the reactor, and methyl magnesium chloride tetrahydrofuran solution was added dropwise under controlled temperature. After the addition was completed, the reaction was carried out under controlled temperature. After the reaction was completed, intermediate K was obtained by hydrolysis and post-treatment purification. Preparation of intermediate L: Intermediate K, concentrated sulfuric acid, and toluene were added to a reactor, stirred and heated to carry out the reaction. After the reaction was completed, intermediate L was obtained by hydrolysis and post-treatment purification.

[0011] The present invention also discloses an application of a phosphine-containing TADF compound, wherein the phosphine-containing TADF compound is used in an organic electroluminescent device.

[0012] Furthermore, the organic electroluminescent device includes a cathode, an anode, and an organic thin film layer sandwiched between the cathode and the anode, wherein the organic thin film layer contains a light-emitting layer, and at least one layer of the organic thin film layer contains at least one of the phosphine-containing TADF compounds.

[0013] Furthermore, the number of light-emitting layers in the organic thin film layer is ≥1, and the light-emitting layer contains the phosphine-containing TADF compound.

[0014] Furthermore, the phosphine-containing TADF compound is the main material of the light-emitting layer.

[0015] The beneficial effects of this invention are: The phosphine-containing TADF compound of this invention utilizes the electron-deficient nature of boron atoms to form spatially separated HOMO-LUMO orbitals with the donor group, significantly reducing the singlet-triple energy level difference. This ensures that triplet excitons can be converted into singlet excitons via anti-intersystem crossing, significantly improving exciton utilization and external quantum efficiency. Furthermore, thanks to the resonance structure of boron, molecular rigidity is increased, non-radiative transitions are reduced, and fluorescence quantum yield is improved. Additionally, the phosphoxy group is a strong electron-withdrawing group, which polarizes the molecular, improving electrical properties and thus enhancing luminescence efficiency.

[0016] The phosphine-containing TADF compound of this invention, through structural design, has prepared a compound with a high molecular rigidity, which increases the distillation decomposition temperature and glass transition temperature, effectively improving the thermal stability of the compound, thereby significantly improving the service life of organic electroluminescent devices using this phosphine-containing TADF compound. Attached Figure Description

[0017] Figure 1 This is a structural diagram of an organic electroluminescent device in an application example of the present invention. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in detail below. The present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used is for describing particular embodiments only and is not intended to limit the invention.

[0020] I. Compound Preparation Examples Example 1 The main raw materials were 4-tert-butylaniline (CAS: 769-92-6), 1-bromo-2,5-dichloro-3-fluorobenzene (CAS: 202865-57-4), dimethyl phosphite (CAS: 868-85-9), m-bromoiodobenzene (CAS: 591-18-4), m-bromophenol (CAS: 591-20-8), 5-bromo-2-iodophenylacetic acid (CAS: 702641-01-8), and p-chlorophenylboronic acid (CAS: 1679-18-1), all of which were purchased. The synthetic intermediates were designated A, B, C, D, E, F, G, H, I, J, K, L, M, and N. The final product was designated compound O, which is a phosphine-containing TADF compound. The specific synthetic method is as follows: 1. Synthetic route of intermediate A: ; Preparation of Intermediate A: Using 4-tert-butylaniline (CAS: 769-92-6) and 1-bromo-2,5-dichloro-3-fluorobenzene (CAS: 202865-57-4) as main raw materials, 10.0 g (41.0 mmol) of 1-bromo-2,5-dichloro-3-fluorobenzene, 6.1 g (41.0 mmol) of 4-tert-butylaniline, 5.9 g (61.5 mmol) of sodium tert-butoxide, and Pd2(dba)3(tris(dibenzylacetone)dipalladium(0) 1.92 g (2.1 mmol) of X-PHOS (2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl; CAS:564483-18-7) and 100.0 g of toluene were added. The mixture was heated to 85 °C and reacted for 6 hours. TLC showed no residual 4-tert-butylaniline. After the reaction was deemed satisfactory, the mixture was hydrolyzed, washed with water, dissolved in toluene and passed through a silica gel column, recrystallized in toluene / petroleum ether, and dried to obtain intermediate A 10.7 g. HPLC: 99.55%, yield 83.6%.

[0021] 1H NMR: δ 7.41 (s, 1H), 7.29-7.23 (m, 2H), 7.18 (dd, J = 8.0, 1.5 Hz,1H), 7.10 (d, J = 1.6 Hz, 1H), 7.09-7.03 (m, 2H), 1.35 (s, 7H).

[0022] Elemental analysis of the structure: The molecular formula is C 16 H 16 Cl2FN; LC-MS product molecular weight: 311.06.

[0023] 2. Synthetic route of intermediate B: ; Preparation of intermediate B: Using dimethyl phosphite (CAS: 868-85-9) as the main raw material, 37.8 ml of methyl magnesium chloride solution (CAS: 676-58-4; 3.0M) and 50.0 g of tetrahydrofuran were added to a 250 ml three-necked flask. The temperature was controlled below -5.0℃, and 5.0 g (45.4 mmol) of dimethyl phosphite was added dropwise. After the addition was complete, the mixture was kept at -5.0℃ for 3 hours. A sample was taken for GC monitoring, and no dimethyl phosphite remained. After the reaction was qualified, 2.4 g of intermediate B was obtained after hydrolysis, dichloromethane extraction, and solvent removal, with a yield of 69.1% and a GC value of 99.15%.

[0024] 1 H NMR: δ 1.49 (d, J = 13.0 Hz, 1H).

[0025] Elemental analysis: molecular formula is C2H7OP; molecular weight of product detected by GC-MS: 78.02.

[0026] 3. Synthetic route of intermediate C: ; Preparation of intermediate C: Using intermediate B and m-bromoiodobenzene (CAS: 591-18-4) as the main raw materials, 10.0 g (128.1 mmol) of intermediate B, 36.1 g (128.1 mmol) of m-bromoiodobenzene, 25.9 g (256.2 mmol) of triethylamine (CAS: 121-44-8), 1.48 g (1.28 mmol) of tetra(triphenylphosphine)palladium (CAS: 14221-01-3), and 150.0 g of dioxane were added to a 250 ml three-necked flask. The mixture was stirred and heated to 60-70 °C and kept at this temperature for 5 h. TLC showed no residual intermediate B. After the reaction was deemed satisfactory, the intermediate was extracted with toluene, washed with water, desolventized, dissolved in toluene, passed through a silica gel column, desolventized again, recrystallized, and dried to obtain 25.0 g of intermediate C. GC: 99.03%, yield: 84.1%.

[0027] 1 H NMR: δ 7.56 (dt, J = 7.5, 1.5 Hz, 1H), 7.51 (dt, J = 13.2, 1.5 Hz, 1H), 7.39 (ddt, J = 13.4, 7.5, 1.6 Hz, 1H), 7.27 (td, J = 7.5, 4.2 Hz, 1H),2.01 (d, J = 13.0 Hz, 5H).

[0028] Elemental analysis of the structure: The molecular formula is C8H. 10 BrOP; GC-MS product molecular weight: 231.97.

[0029] 4. Synthetic route of intermediate D: ; Preparation of intermediate D: Using intermediates A and C as main raw materials, 10.0 g (32.1 mmol) of intermediate A, 7.4 g (32.1 mmol) of intermediate C, 4.6 g (48.2 mmol) of sodium tert-butoxide, 0.29 g (0.32 mmol) of (tris(dibenzylacetone))dipalladium(O), 0.31 g (0.64 mmol) of 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, and 150.0 g of toluene were added to a 250 ml three-necked flask. After the addition was complete, the mixture was heated to 85 °C and reacted. After 6 h of reaction, TLC was performed and no intermediate C remained. After the reaction was deemed satisfactory, the intermediate D was obtained by hydrolysis, washing with water, dissolving in toluene and passing through a silica gel column, recrystallizing in toluene / petroleum ether, and drying. The yield was 13.0 g of intermediate D. HPLC: 99.56%, yield 87.5%.

[0030] 1 H NMR: δ 7.45 (d, J = 1.6 Hz, 1H), 7.38 (ddt, J = 13.2, 7.3, 1.5 Hz,1H), 7.31 (td, J = 7.5, 4.2 Hz, 1H), 7.28-7.23 (m, 2H), 7.23-7.15 (m, 2H),7.06-7.00 (m, 2H), 6.91 (dt, J = 13.5, 1.6 Hz, 1H), 2.02 (d, J = 13.0 Hz,5H), 1.35 (s, 7H).

[0031] Elemental analysis of the structure: The molecular formula is C 24 H 25 Cl2FNOP; LC-MS product molecular weight: 463.10.

[0032] 5. Synthetic route of intermediate E: ; Preparation of intermediate E: Using intermediate B and m-bromophenol as the main raw materials, 10.0 g (128.1 mmol) of intermediate B, 22.0 g (128.1 mmol) of m-bromophenol (CAS: 591-20-8), 25.9 g (256.2 mmol) of triethylamine, 1.48 g (1.28 mmol) of tetra(triphenylphosphine)palladium, and 150.0 g of dioxane were added to a 250 ml three-necked flask. The mixture was stirred and heated to 70-80 °C and kept at this temperature for 5 hours. TLC was then performed to check for any remaining intermediate B. After the reaction was deemed satisfactory, the intermediate was extracted with toluene, washed with water, desolventized, dissolved in toluene, passed through a silica gel column, desolventized again, recrystallized, and dried to obtain 18.6 g of intermediate E. GC: 99.66%, yield: 85.2%.

[0033] 1 H NMR: δ 8.70 (s, 1H), 7.21 (td, J = 7.5, 4.1 Hz, 1H), 7.03-6.94 (m,2H), 6.87 (dt, J=13.2, 1.5 Hz, 1H), 1.98 (d, J=13.0 Hz, 5H).

[0034] Elemental analysis of the structure: The molecular formula is C8H. 11 O2P; GC-MS product molecular weight: 170.05.

[0035] 6. Synthetic route of intermediate F: ; Preparation of intermediate F: Using intermediates D and E as main raw materials, 10.0 g (58.8 mmol) of intermediate E, 27.2 g (58.8 mmol) of intermediate D, 16.3 g (117.6 mmol) of potassium carbonate, and 150.0 g of DMF were added to a 250 ml three-necked flask. The mixture was stirred and heated to 90–100 °C and kept at this temperature for 10 h. TLC showed no residual intermediate E. After the reaction was deemed satisfactory, the intermediate was hydrolyzed, extracted with toluene, washed with water, desolventized, dissolved in toluene and passed through a silica gel column, desolventized again, recrystallized, and dried to obtain 31.8 g of intermediate F. HPLC: 99.48%, yield 88.3%.

[0036] 1 H NMR: δ 7.35-7.17 (m, 2H), 7.13-7.02 (m, 1H), 6.97-6.86 (m, 1H), 2.12-2.01 (m, 3H), 1.35 (s, 2H).

[0037] Elemental analysis of the structure: The molecular formula is C 32 H 35 Cl2NO3P2; LC-MS product molecular weight: 613.15.

[0038] 7. Synthetic route of intermediate G: ; Preparation of intermediate G: Using intermediate F and pinacol diborate as the main raw materials, 10.0 g (16.3 mmol) of intermediate F, 10.4 g (40.8 mmol) of pinacol diborate, 8.0 g (81.5 mmol) of potassium acetate, 0.036 g (0.16 mmol) of palladium acetate, 0.13 g (0.32 mmol) of 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl (CAS: 657408-07-6) and 150.0 g of xylene were added to a 250 ml three-necked flask. The mixture was stirred and heated to 100-110 °C and kept at this temperature for 10 h. TLC showed no residual intermediate F. After the reaction was deemed satisfactory, the intermediate was hydrolyzed, washed with water, dissolved in xylene, passed through a silica gel column, recrystallized from toluene, and dried to obtain 11.0 g of intermediate G. HPLC: 99.66%, yield 84.9%.

[0039] 1 H NMR: δ 7.42-7.28 (m, 1H), 7.31-7.24 (m, 1H), 7.26-7.11 (m, 1H), 7.06-7.01 (m, 1H), 7.00-6.87 (m, 1H), 2.11-2.01 (m, 3H), 1.36 (s, 2H), 1.24 (d,J = 4.0 Hz, 7H).

[0040] Elemental analysis of the structure: The molecular formula is C 44 H 59 B2NO7P2; LC-MS product molecular weight: 797.40.

[0041] 8. Synthetic route of intermediate H: ; Preparation of intermediate H: Using 5-bromo-2-iodophenylacetic acid (CAS: 702641-01-8) as the main raw material, 10.0 g (29.3 mmol) of 5-bromo-2-iodophenylacetic acid, 3.2 g (29.3 mmol) of concentrated sulfuric acid, and 100.0 g of methanol were added sequentially to a 250 ml three-necked flask. The mixture was stirred and heated to 60-70 °C and kept at this temperature for 4 hours. TLC showed no remaining 5-bromo-2-iodophenylacetic acid. After the reaction was deemed satisfactory, intermediate H was obtained by hydrolysis, toluene extraction, water washing, dissolution in toluene, silica gel column chromatography, and solvent removal. The yield was 10.1 g of intermediate H. HPLC: 98.63%, yield 97.3%.

[0042] 1 H NMR: δ 7.68 (d, J = 7.5 Hz, 1H), 7.44 (q, J = 1.1 Hz, 1H), 7.31 (dd, J = 7.5, 1.5 Hz, 1H), 3.71 (d, J = 0.9 Hz, 2H), 3.66 (s, 2H).

[0043] Elemental analysis: molecular formula is C9H8BrIO2; molecular weight of product determined by LC-MS: 353.88.

[0044] 9. Synthetic route of intermediate I: ; Preparation of Intermediate I: Using Intermediate H and p-chlorophenylboronic acid (CAS: 1679-18-1) as the main raw materials, 10.0 g (64.1 mmol) of p-chlorophenylboronic acid, 23.8 g (67.3 mmol) of Intermediate H, 22.2 g (160.3 mmol) of potassium carbonate, 51.8 g of water, 3.70 g (3.2 mmol) of tetra(triphenylphosphine)palladium, and 100.0 g of tetrahydrofuran were added sequentially to a 250 ml three-necked flask. The mixture was stirred and heated to 60-70 °C and kept at this temperature for 5 h. TLC showed no remaining p-chlorophenylboronic acid. After the reaction was deemed satisfactory, the mixture was extracted with toluene, washed with water, desolventized, dissolved in petroleum ether, passed through a silica gel column, and desolventized again to obtain 20.8 g of Intermediate I. GC: 96.6%, yield 95.6%.

[0045] 1 H NMR: δ 7.55-7.49 (m, 3H), 7.49 (dd, J = 7.5, 1.4 Hz, 1H), 7.44 (d,J = 7.5 Hz, 1H), 7.38-7.32 (m, 2H), 3.75 (d, J = 1.1 Hz, 2H), 3.65 (s, 2H).

[0046] Elemental analysis of the structure: The molecular formula is C15 H 12 BrClO2; GC-MS analysis of the product molecular weight: 339.97.

[0047] 10. Synthetic route of intermediate J: ; Preparation of intermediate J: Using intermediate I as the main raw material, 10.0 g (29.4 mmol) of intermediate I and 100.0 g of tetrahydrofuran were added sequentially to a 250 ml three-necked flask. 32.3 ml of lithium bis(trimethylsilyl)amino (CAS: 4039-32-1; 2M) of LiHMDS was added dropwise at 10–20 °C. After the addition was complete, the temperature was maintained at 10–20 °C for 4 h. Then, 8.4 g (58.8 mmol) of iodomethane was added dropwise. After the addition was complete, the temperature was maintained at 10–20 °C for 5 h. TLC analysis showed no remaining intermediate I. After the reaction was deemed satisfactory, intermediate J was obtained by hydrolysis, toluene extraction, water washing, solvent removal, dissolution in petroleum ether, column chromatography, and solvent removal to yield 10.4 g of intermediate J. GC: 94.3%, yield 96.4%.

[0048] 1 H NMR: δ 7.58 (d, J = 1.5 Hz, 1H), 7.53 (td, J = 7.5, 1.4 Hz, 3H), 7.43 (d, J = 7.5 Hz, 1H), 7.38-7.32 (m, 2H), 3.71 (s, 2H), 1.58 (s, 4H).

[0049] Elemental analysis of the structure: The molecular formula is C 17 H 16 BrClO2; GC-MS analysis of the product molecular weight: 368.00.

[0050] 11. Synthetic route of intermediate K: ; Preparation of intermediate K: Using intermediate J as the main raw material, 10.0 g (27.2 mmol) of intermediate J and 100.0 g of tetrahydrofuran were added sequentially to a 250 ml three-necked flask. 18.1 ml of methyl magnesium chloride tetrahydrofuran solution (CAS: 676-58-4; 3M) was added dropwise while maintaining the temperature at 10–20 °C. After the addition was complete, the temperature was maintained at 10–20 °C for 2 h. TLC analysis showed no remaining intermediate J. After the reaction was deemed satisfactory, the intermediate K was obtained by hydrolysis, ethyl acetate extraction, washing with water, solvent removal, dissolution in toluene, silica gel column chromatography, and solvent removal. 9.3 g of intermediate K was obtained, with a GC content of 98.2% and a yield of 93.3%.

[0051] 1H NMR: δ 7.56-7.42 (m, 1H), 7.40-7.34 (m, 0H), 1.43 (s, 1H), 1.31 (s, 1H).

[0052] Elemental analysis of the structure: The molecular formula is C 18 H 20 BrClO; GC-MS analysis of the product molecular weight: 368.04.

[0053] 12. Synthetic route of intermediate L: ; Preparation of intermediate L: Using intermediate K as the main raw material, 10.0 g (27.2 mmol) of intermediate K, 11.6 g (108.8 mmol) of concentrated sulfuric acid, and 100.0 g of toluene were added sequentially to a 250 ml three-necked flask. The mixture was stirred and heated to 80-90 °C and kept at this temperature for 2 h. TLC was then performed to check that no intermediate K remained. After the reaction was deemed satisfactory, the intermediate L was obtained by hydrolysis, toluene extraction, water washing, solvent removal, dissolution in n-hexane, silica gel column chromatography, solvent removal, recrystallization in n-hexane, and drying. 7.7 g of intermediate L was obtained. GC: 99.55%, yield: 80.9%.

[0054] 1 H NMR: δ 7.69 (d, J = 1.5 Hz, 1H), 7.61 (d, J = 7.5 Hz, 1H), 7.57(d, J = 7.5 Hz, 1H), 7.57-7.51 (m, 2H), 7.24 (dd, J = 7.5, 1.5 Hz, 1H), 1.39 (s, 12H).

[0055] Elemental analysis of the structure: The molecular formula is C 18 H 18 BrCl; GC-MS analysis of the product molecular weight: 350.03.

[0056] 13. Synthetic route of intermediate M: ; Preparation of intermediate M: Using intermediates G and L as main raw materials, 10.0 g (28.6 mmol) of intermediate L, 22.8 g (28.6 mmol) of intermediate G, 9.9 g (71.5 mmol) of potassium carbonate, 23.1 g of water, 0.34 g (0.29 mmol) of tetra(triphenylphosphine)palladium, and 150.0 g of tetrahydrofuran were added to a 250 ml three-necked flask. The mixture was stirred and heated to 60-70 °C and kept at this temperature for 10 h. TLC showed no residual intermediate L. After the reaction was deemed satisfactory, the intermediate was extracted with toluene, washed with water, desolventized, dissolved in toluene and passed through a silica gel column, desolventized again, recrystallized from toluene, and dried to obtain 23.5 g of intermediate M. HPLC: 99.18%, yield 87.3%.

[0057] 1 H NMR: δ 7.42-7.28 (m, 2H), 7.28-7.15 (m, 1H), 7.06-6.95 (m, 1H), 6.91 (ddt, J = 13.3, 4.7, 1.5 Hz, 1H), 2.11-2.01 (m, 3H), 1.38 (d, J = 16.7Hz, 5H), 1.23 (s, 3H).

[0058] Elemental analysis of the structure: The molecular formula is C 56 H 65 BClNO5P2; LC-MS analysis of the product molecular weight: 939.41.

[0059] 14. Synthetic route of intermediate N: ; Preparation of intermediate N: Using intermediate M as the main raw material, 20.0 g (150.0 mmol) of aluminum trichloride and 20.0 g of toluene were added sequentially to a 250 ml three-necked flask. A mixed solution of intermediate M / triethylamine / toluene (compound M (17.7 g, 18.8 mmol); triethylamine (1.9 g, 18.8 mmol); toluene 94.0 g) was added dropwise at 60–70 °C. After the addition was complete, the temperature was maintained at 60–70 °C for 10 h. TLC was then performed to check for any remaining intermediate M. After the reaction was deemed satisfactory, the intermediate N was obtained by hydrolysis, washing with water, solvent removal, dissolution in toluene, silica gel column chromatography, solvent removal, recrystallization in toluene, and drying. 13.8 g of intermediate N was obtained. HPLC: 99.18%, yield 89.3%.

[0060] 1H NMR: δ 7.71 (t, J = 0.8 Hz, 1H), 7.59 (d, J = 7.5 Hz, 1H), 7.52(d, J = 1.5 Hz, 1H), 7.48 (dd, J = 7.5, 4.1 Hz, 1H), 7.43-7.37 (m, 3H), 7.31(dd, J = 7.4, 1.5 Hz, 1H), 7.26-7.21 (m, 2H), 7.14 (dd, J = 13.3, 1.5 Hz,1H), 7.14-7.08 (m, 2H), 7.00 (dtd, J = 13.2, 7.6, 1.6 Hz, 2H), 6.96-6.90 (m, 2H), 6.78 (d, J = 1.4 Hz, 1H), 2.05 (dd, J = 13.0, 0.9 Hz, 10H), 1.39 (s, 9H), 1.36 (s, 7H).

[0061] Elemental analysis of the structure: The molecular formula is C 50 H 51 BClNO3P2; LC-MS analysis of the product molecular weight: 821.31.

[0062] Synthetic route of compound 2: ; The specific preparation steps are as follows: Preparation of Compound 2: Using intermediate N and deuterated phenylboronic acid (CAS: 215527-70-1) as the main raw materials, under nitrogen protection, 30 g (36.5 mmol) of intermediate N, 4.6 g (36.5 mmol) of deuterated phenylboronic acid, 12.6 g (91.3 mmol) of potassium carbonate, 29.4 g of water, 0.40 g (1.8 mmol) of palladium acetate, and 1.72 g (3.6 mmol) of X-PHOS were added sequentially to a 1 L three-necked flask. 450 g of tetrahydrofuran was added and stirred. The mixture was heated to 50–60 °C and maintained at this temperature. The reaction was monitored by TLC. After approximately 6 hours, the reaction was completely complete with no intermediate N remaining. The mixture was then allowed to stand and separate into layers. The organic phase was extracted with toluene, washed with water, desolventized, dissolved in toluene and passed through an alkaline alumina column, recrystallized from tetrahydrofuran / industrial ethanol, and dried to obtain 26.0 g of compound 2 as a white solid. HPLC: 99.98%, yield 81.9%.

[0063] Elemental analysis of the structure: The molecular formula is C 56 H 51 D5BNO3P2; LC-MS analysis of the product molecular weight: 868.41.

[0064] 1 H NMR: δ 7.71 (dd, J = 8.8, 1.4 Hz, 2H), 7.48 (dd, J = 7.5, 4.1 Hz, 1H), 7.43-7.35 (m, 4H), 7.31 (dd, J = 7.5, 1.5 Hz, 1H), 7.26-7.21 (m, 2H),7.14 (dd, J = 13.3, 1.5 Hz, 1H), 7.12-7.07 (m, 2H), 7.00 (dtd, J = 13.2, 7.6,1.6 Hz, 2H), 6.96-6.90 (m, 2H), 6.78 (d, J = 1.4 Hz, 1H), 2.05 (dd, J = 13.0,0.9 Hz, 10H), 1.39 (s, 12H), 1.36 (s, 7H).

[0065] Example 2 Synthetic route of compound 3: ; The specific preparation steps are as follows: Preparation of Compound 3: Using intermediate N and 4-biphenylboronic acid (CAS: 5122-94-1) as the main raw materials, under nitrogen protection, 30 g (36.5 mmol) of intermediate N, 7.2 g (36.5 mmol) of 4-biphenylboronic acid, 12.6 g (91.3 mmol) of potassium carbonate, 29.4 g of water, 0.40 g (1.8 mmol) of palladium acetate, and 1.72 g (3.6 mmol) of X-PHOS were added sequentially to a 1 L three-necked flask. 450 g of tetrahydrofuran was added and stirred. The mixture was heated to 50–60 °C and maintained at this temperature. The reaction was monitored by TLC. After approximately 8 hours, the reaction was complete, with no intermediate N remaining. The mixture was then allowed to stand and separate into layers. The organic phase was extracted with toluene, washed with water, desolventized, dissolved in toluene and passed through an alkaline alumina column, recrystallized from tetrahydrofuran / industrial ethanol, and dried to obtain 28.7 g of compound 3 as a white solid. HPLC: 99.97%, yield 83.6%.

[0066] Elemental analysis of the structure: The molecular formula is C 62 H 60 BNO3P2.

[0067] LC-MS analysis of the product molecular weight: 939.41; 1H NMR: δ 7.63 (d, J = 0.7 Hz, 1H), 7.64-7.55 (m, 1H), 7.44-7.37 (m, 1H), 7.41-7.31 (m, 1H), 7.26-7.20 (m, 1H), 7.17-7.08 (m, 1H), 7.05-6.90 (m, 1H), 2.05 (dd, J = 13.0, 0.9 Hz, 3H), 1.39 (s, 3H), 1.36 (s, 2H).

[0068] Example 3 Synthetic route of compound 16: ; The specific preparation steps are as follows: Preparation of Compound 16: Using intermediate N and 2-naphthoboric acid (CAS: 32316-92-0) as the main raw materials, under nitrogen protection, 30 g (36.5 mmol) of intermediate N, 6.3 g (36.5 mmol) of 2-naphthoboric acid, 12.6 g (91.3 mmol) of potassium carbonate, 29.4 g of water, 0.40 g (1.8 mmol) of palladium acetate, and 1.72 g (3.6 mmol) of X-PHOS were added sequentially to a 1 L three-necked flask. 450 g of tetrahydrofuran was added and stirred. The mixture was heated to 50–60 °C and maintained at this temperature. The reaction was monitored by TLC. After approximately 10 hours, the reaction was completely complete, with no intermediate N remaining. The mixture was then allowed to stand and separate into layers. The organic phase was extracted with toluene, washed with water, desolventized, dissolved in toluene, passed through a silica gel column, recrystallized in toluene / petroleum ether, and dried to obtain 28.5 g of compound 16 as a white solid. HPLC: 99.98%, yield 85.5%.

[0069] Elemental analysis of the structure: The molecular formula is C 60 H 58 BNO3P2; LC-MS analysis of the product molecular weight: 913.40.

[0070] 1H NMR: δ 8.02-7.94 (m, 2H), 7.92-7.86 (m, 1H), 7.78 (d, J = 1.6 Hz,1H), 7.73-7.66 (m, 2H), 7.59-7.48 (m, 2H), 7.51-7.45 (m, 2H), 7.43-7.35 (m,4H), 7.26-7.20 (m, 3H), 7.17-7.10 (m, 1H), 7.13-7.08 (m, 2H), 7.00 (dtd, J =13.2, 7.6, 1.6 Hz, 2H), 6.96-6.90 (m, 2H), 6.78 (d, J = 1.4 Hz, 1H), 2.05(dd,J = 13.0, 0.9 Hz, 10H), 1.39 (s, 12H), 1.36 (s, 7H).

[0071] Example 4 Synthetic route of compound 18: ; The specific preparation steps are as follows: Preparation of Compound 18: Using intermediate N and 1-pyreneboronic acid (CAS: 164461-18-1) as the main raw materials, under nitrogen protection, 30 g (36.5 mmol) of intermediate N, 9.0 g (36.5 mmol) of 1-pyreneboronic acid, 12.6 g (91.3 mmol) of potassium carbonate, 29.4 g of water, 0.40 g (1.8 mmol) of palladium acetate, and 1.72 g (3.6 mmol) of X-PHOS were added sequentially to a 1 L three-necked flask. The mixture was stirred with 450 g of dioxane and heated to 70–80 °C. The reaction was monitored by TLC. After about 6 hours, the reaction was completely completed and no intermediate N remained. The mixture was then allowed to stand and separate into layers. The organic phase was extracted with toluene, washed with water, desolventized, dissolved in toluene and passed through a silica gel column, recrystallized from toluene / industrial ethanol, and dried to obtain 30.5 g of compound 18 as a white solid. HPLC: 99.99%, yield 84.5%.

[0072] Elemental analysis of the structure: The molecular formula is C 66 H 60 BNO3P2; LC-MS analysis of the product molecular weight: 987.41.

[0073] 1H NMR: δ 8.26 (dt, J = 7.3, 1.8 Hz, 1H), 8.17 (dd, J = 7.6, 1.6 Hz, 1H), 8.05 (dq, J = 7.5, 1.4 Hz, 2H), 8.02-7.94 (m, 2H), 7.80 (d, J = 1.4Hz,1H), 7.74 (d, J = 7.3 Hz, 1H), 7.69 (d, J = 1.5 Hz, 1H), 7.65 (d, J = 7.5 Hz,1H), 7.56 (ddd, J = 14.8, 7.5, 1.6 Hz, 2H), 7.48 (dd, J = 7.5, 4.1 Hz, 1H),7.43-7.37 (m, 2H), 7.37 (d, J = 7.5 Hz, 1H), 7.26-7.20 (m, 3H), 7.17-7.10 (m,1H), 7.13-7.08 (m, 2H), 7.04-6.90 (m, 4H), 6.78 (d, J = 1.4 Hz, 1H), 2.05 (dd, J = 13.0, 0.9 Hz, 10H), 1.39 (s, 12H), 1.36 (s, 7H).

[0074] Example 5 Synthetic route of compound 42: ; The specific preparation steps are as follows: Preparation of Compound 42: Using intermediate N and 4-dibenzofuranboronic acid (CAS: 100124-06-9) as the main raw materials, under nitrogen protection, 30 g (36.5 mmol) of intermediate N, 7.7 g (36.5 mmol) of 4-dibenzofuranboronic acid, 12.6 g (91.3 mmol) of potassium carbonate, 29.4 g of water, 0.40 g (1.8 mmol) of palladium acetate, and 1.72 g (3.6 mmol) of X-PHOS were added sequentially to a 1 L three-necked flask. 300 g of toluene and 150 g of industrial ethanol were added and stirred. The mixture was heated to 60–70 °C and maintained at this temperature. The reaction was monitored by TLC. After about 8 hours, the reaction was completely completed with no intermediate N remaining. The mixture was then allowed to stand and separate into layers. The organic phase was washed with water, desolventized, dissolved in toluene, passed through a silica gel column, recrystallized from tetrahydrofuran / industrial ethanol, and dried to obtain 30.8 g of compound 42 as a white solid. HPLC: 99.99%, yield 88.6%.

[0075] Elemental analysis of the structure: The molecular formula is C 62 H 58BNO4P2; LC-MS analysis of the product molecular weight: 953.39.

[0076] 1 H NMR: δ 8.02 (ddd, J = 11.7, 7.5, 1.5 Hz, 1H), 7.71 (dd, J = 6.6,1.4 Hz, 1H), 7.52-7.34 (m, 3H), 7.26-7.20 (m, 1H), 7.17-7.08 (m, 1H), 7.05-6.90 (m, 2H), 2.05 (dd, J = 13.0, 0.9 Hz, 4H), 1.39 (s, 4H), 1.36 (s, 3H).

[0077] Example 6 Synthetic route of compound 50: ; The specific preparation steps are as follows: Preparation of Compound 50: Using intermediate N and 9,9-dimethylfluorene-1-boronic acid (CAS: 1251825-71-4) as the main raw materials, intermediate N was added sequentially to a 1L three-necked flask under nitrogen protection. 30 g (36.5 mmol), 8.7 g (36.5 mmol) of 9,9-dimethylfluorene-1-boric acid, 12.6 g (91.3 mmol) of potassium carbonate, 29.4 g of water, 0.40 g (1.8 mmol) of palladium acetate, and 1.72 g (3.6 mmol) of X-PHOS were mixed with 300 g of toluene and 150 g of industrial ethanol and heated to 60–70 °C. The reaction was monitored by TLC. The reaction was completely completed in about 8 hours with no intermediate N remaining. The mixture was then allowed to stand and separate into layers. The organic phase was washed with water, desolventized, dissolved in toluene, passed through a silica gel column, recrystallized from tetrahydrofuran / industrial ethanol, and dried to obtain 31.2 g of compound 50 as a white solid. HPLC: 99.98%, yield 87.3%.

[0078] Elemental analysis of the structure: The molecular formula is C 65 H 64 BNO3P2; LC-MS analysis of the product molecular weight: 979.45.

[0079] 1H NMR: δ 7.67-7.53 (m, 1H), 7.51-7.32 (m, 3H), 7.26-7.21 (m, 1H), 7.17-7.08 (m, 1H), 7.05-6.90 (m, 1H), 2.05 (dd, J = 13.0, 0.9 Hz, 3H), 1.61 (s, 1H), 1.39 (s, 3H), 1.36 (s, 2H).

[0080] Example 7 Synthetic route of compound 58: ; The specific preparation steps are as follows: Preparation of Compound 58: Using intermediate N and (9-phenyl-9H-carbazole-1-yl)boronic acid (CAS: 1333002-41-7) as the main raw materials, intermediate N was added sequentially to a 1L three-necked flask under nitrogen protection. 30 g (36.5 mmol), 11.1 g (36.5 mmol) of (9-phenyl-9H-carbazole-1-yl)boric acid, 12.6 g (91.3 mmol) of potassium carbonate, 29.4 g of water, 0.40 g (1.8 mmol) of palladium acetate, and 1.72 g (3.6 mmol) of X-PHOS were mixed with 450 g of tetrahydrofuran and heated to 60–70 °C. The reaction was monitored by TLC. The reaction was completely completed in about 12 hours with no intermediate N remaining. The mixture was then allowed to stand and separate into layers. The organic phase was extracted with toluene, washed with water, desolventized, dissolved in toluene and passed through a silica gel column, recrystallized in toluene / petroleum ether, and dried to give 31.1 g of compound 58 as a white solid. HPLC: 99.97%, yield 82.8%.

[0081] Elemental analysis of the structure: The molecular formula is C 68 H 63 BN2O3P2; LC-MS analysis of the product molecular weight: 1028.44.

[0082] 1 H NMR: δ 7.59-7.34 (m, 4H), 7.34-7.20 (m, 2H), 7.17-7.08 (m, 1H), 7.04-6.90 (m, 1H), 2.05 (dd, J = 13.0, 0.9 Hz, 3H), 1.39 (s, 3H), 1.36 (s,2H).

[0083] Example 8 Synthetic route of compound 59: ; The specific preparation steps are as follows: Preparation of Compound 59: Using intermediate N and (9-phenyl-9H-carbazole-2-yl)boric acid (CAS: 1001911-63-2) as the main raw materials, intermediate N was added sequentially to a 1L three-necked flask under nitrogen protection. 30 g (36.5 mmol), 11.1 g (36.5 mmol) of (9-phenyl-9H-carbazole-2-yl)boric acid, 12.6 g (91.3 mmol) of potassium carbonate, 29.4 g of water, 0.40 g (1.8 mmol) of palladium acetate, and 1.72 g (3.6 mmol) of X-PHOS were mixed with 450 g of tetrahydrofuran and stirred. The mixture was heated to 60–70 °C and maintained at this temperature. The reaction was monitored by TLC. After about 12 hours, the reaction was completely completed with no intermediate N remaining. The mixture was then allowed to stand and separate into layers. The organic phase was extracted with toluene, washed with water, desolventized, dissolved in toluene and passed through a silica gel column, recrystallized in toluene / petroleum ether, and dried to obtain 31.8 g of compound 59 as a white solid. HPLC: 99.99%, yield 84.6%.

[0084] Elemental analysis of the structure: The molecular formula is C 68 H 63 BN2O3P2; LC-MS analysis of the product molecular weight: 1028.44.

[0085] 1 H NMR: δ 8.16-8.09 (m, 1H), 8.07 (d, J = 7.5 Hz, 1H), 7.75 (d, J =1.4 Hz, 1H), 7.68 (dd, J = 8.9, 1.5 Hz, 2H), 7.65-7.57 (m, 2H), 7.55-7.43 (m,5H), 7.40 (ddd, J = 7.6, 2.9, 1.3 Hz, 3H), 7.37 (d, J = 7.5 Hz, 1H), 7.34-7.27 (m, 1H), 7.31-7.24 (m, 2H), 7.26-7.19 (m, 3H), 7.17-7.10 (m, 1H), 7.13-7.08 (m,2H), 7.04-6.90 (m, 4H), 6.78 (d, J = 1.4 Hz, 1H), 2.05 (dd, J = 13.0,0.9 Hz, 10H), 1.39 (s, 12H), 1.36 (s, 7H).

[0086] II. Device Application Examples The structure of organic electroluminescent devices is as follows Figure 1As shown, the layers stacked from bottom to top are: substrate, anode, hole injection layer (HIM), hole transport layer 1 (HTL1), hole transport layer 2 (HTL2), light-emitting layer (EML), electron transport layer (ETL), electron injection layer (EIL), and cathode.

[0087] The specific fabrication method of organic electroluminescent devices is as follows: A 130 nm thick indium tin oxide (ITO) film was coated onto a glass substrate and used as the anode, which was then treated with nitrogen plasma for 100 seconds. The substrate was subsequently mounted on a substrate support in a vacuum chamber at 10... -6 -10 -8 At a vacuum pressure of mbar and a rate of 0.2-1.0 Å / sec, the functional layer materials were deposited sequentially onto the ITO substrate using a vapor deposition method.

[0088] The hole injection layer consists of a 10 nm thick layer of 97 wt% HTL1 and 3 wt% HIM. Hole transport layer 1 is an 80 nm thick HTL1, and hole transport layer 2 is a 10 nm thick HTL2. The emitting layer is 25 nm thick and consists of 2 wt% emitting host material and 98 wt% BH1. A 15 nm thick ETL is deposited on top of the emitting layer as an electron transport layer. Finally, a 1 nm thick LiF layer is deposited as an electron injection layer, and a 50 nm thick Al layer is deposited on top of the electron injection layer as a cathode. This forms the organic electroluminescent device.

[0089] The materials used are listed in Table 1 below, and the main light-emitting material is either the compound obtained in Examples 1-8 or CP-1. That is, Examples 1-8 and the comparative examples all adopt the preparation method and design structure of the organic electroluminescent device in the application examples. The difference between the examples and the comparative examples is that the main material used in the comparative examples is CP-1 in Table 1, and its chemical structure is shown below.

[0090] .

[0091] The organic electroluminescent devices prepared in Application Examples 1-8 and the Comparative Example were subjected to performance tests. The specific test results are shown in Table 1 below. The test methods involved are as follows: 1) At 10mA / cm 2 The EQE relative to the comparative example was measured at the current density: EQE = (Absolute EQE Example / Absolute EQE Comparative Example) * 100; 2) At 50mA / cm 2 Device lifetime was measured relative to the comparative example at the specified current density: LT95 = (Absolute LT95 Example / Absolute LT95 Comparative Example) * 100.

[0092] Table 1 Performance test results of organic electroluminescent devices

[0093] As shown in Table 1, the organic electroluminescent element prepared using the phosphine-containing TADF compound of the present invention as the main material of the light-emitting layer has improved in terms of service life and luminous efficiency compared with the prior art.

[0094] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] For those skilled in the art, various modifications and improvements can be made without departing from the concept of the present invention, and these modifications and improvements are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A phosphine-containing TADF compound, characterized in that, The general formula structure of the phosphine-containing TADF compound is as follows: ； Ar is any one of phenyl, deuterated phenyl, biphenyl, partially deuterated biphenyl, terphenyl, partially deuterated terphenyl, naphthyl, 9-phenylanthrayl, pyrene, phenanthryl, thionyl, benzoanthrayl, dibenzofuranyl, dibenzothiophene, 9,9-dimethylfluorenyl, 9,9-diphenylfluorenyl, 9-phenyldibenzocarbazoyl, and partially deuterated 9-phenyldibenzocarbazoyl.

2. The phosphine-containing TADF compound according to claim 1, characterized in that, The Ar is selected from any of the following group structures: 。 3. The phosphine-containing TADF compound according to claim 1, characterized in that, The phosphine-containing TADF compound is selected from the following compound structures: 。 4. A method for preparing a phosphine-containing TADF compound according to any one of claims 1-3, characterized in that, The preparation method is as follows: ； Preparation of intermediate M: Intermediate L, intermediate G, potassium carbonate, water, tetra(triphenylphosphine)palladium, and tetrahydrofuran were added to a reactor, and the mixture was stirred and heated to carry out the reaction. After the reaction was completed, intermediate M was obtained by post-treatment and purification. Preparation of intermediate N: Aluminum trichloride and toluene were added to a reactor, and the temperature was controlled. A mixed solution of intermediate M, triethylamine and toluene was added dropwise. After the addition was complete, the temperature was maintained to carry out the reaction. After the reaction was completed, intermediate N was obtained. Preparation of phosphine-containing TADF compound: Intermediate N, Ar-B(OH)2, potassium carbonate, palladium acetate, 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, water, and solvent were added to a reactor, stirred and heated to carry out the reaction. After the reaction was completed, the compound O was obtained by post-treatment purification. The compound O is a phosphine-containing TADF compound.

5. The method for preparing a phosphine-containing TADF compound according to claim 4, characterized in that, The intermediate G is prepared by: ； Preparation of intermediate A: 1-bromo-2,5-dichloro-3-fluorobenzene, 4-tert-butylaniline, sodium tert-butoxide, (tris(dibenzylacetone))dipalladium(O), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl and toluene were added to a reactor and heated to carry out the reaction. After the reaction was completed, intermediate A was obtained by hydrolysis and post-treatment purification. Preparation of intermediate B: Methyl magnesium chloride solution and tetrahydrofuran were added to a reactor, and the temperature was controlled at ≤-5.0℃. Dimethyl phosphite was added dropwise. After the addition was completed, the temperature was maintained at -5.0~0℃ for reaction. After the reaction was completed, intermediate B was obtained by hydrolysis and post-treatment purification. The preparation of intermediate C involves adding intermediate B, m-bromoiodobenzene, triethylamine, tetra(triphenylphosphine)palladium, and dioxane to a reactor, and heating the reactor under stirring conditions. After the reaction is completed, intermediate C is obtained by post-treatment and purification. Preparation of intermediate D: Intermediate A, intermediate C, sodium tert-butoxide, (tris(dibenzylacetone))dipalladium(O), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl and toluene were added to a reactor and heated to carry out the reaction. After the reaction was completed, intermediate D was obtained by post-treatment and purification. Preparation of intermediate E: Intermediate B, m-bromophenol, triethylamine, tetra(triphenylphosphine)palladium, and dioxane were added to a reactor and heated under stirring conditions. After the reaction was completed, intermediate E was obtained by post-treatment and purification. Preparation of intermediate F: Intermediate D, intermediate E, potassium carbonate and DMF were added to the reactor, stirred and heated to carry out the reaction. After the reaction was completed, intermediate F was obtained by hydrolysis and post-treatment purification. Preparation of intermediate G: Intermediate F, pinacol diborate, potassium acetate, palladium acetate, 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl, and xylene were added to a reactor, stirred and heated to carry out the reaction. After the reaction was completed, intermediate G was obtained by hydrolysis and post-treatment purification.

6. The method for preparing a phosphine-containing TADF compound according to claim 4, characterized in that, The intermediate L is prepared by: ； Preparation of intermediate H: 5-bromo-2-iodophenylacetic acid, concentrated sulfuric acid, and methanol were added to a reactor, stirred and heated to carry out the reaction. After the reaction was completed, intermediate H was obtained by hydrolysis and post-treatment purification. Preparation of intermediate I: p-chlorophenylboronic acid, intermediate H, potassium carbonate, water, tetra(triphenylphosphine)palladium, and tetrahydrofuran were added to a reactor, stirred and heated to carry out the reaction. After the reaction was completed, intermediate I was obtained by post-treatment and purification. Preparation of intermediate J: Intermediate I and tetrahydrofuran were added to the reactor. Under controlled temperature conditions, lithium bis(trimethylsilyl)amino was added dropwise. After the addition was completed, the temperature was controlled at 10-20℃ and the reaction was maintained. Iodomethane was added dropwise. After the addition was completed, the temperature was controlled at 10-20℃ and the reaction was carried out. After the reaction was completed, intermediate J was obtained by hydrolysis and post-treatment purification. Preparation of intermediate K: Intermediate J and tetrahydrofuran were added to the reactor, and methyl magnesium chloride tetrahydrofuran solution was added dropwise under controlled temperature. After the addition was completed, the reaction was carried out under controlled temperature. After the reaction was completed, intermediate K was obtained by hydrolysis and post-treatment purification. Preparation of intermediate L: Intermediate K, concentrated sulfuric acid, and toluene were added to a reactor, stirred and heated to carry out the reaction. After the reaction was completed, intermediate L was obtained by hydrolysis and post-treatment purification.

7. An application of a phosphine-containing TADF compound according to any one of claims 1-3, characterized in that, The phosphine-containing TADF compound is used in organic electroluminescent devices.

8. The application of the phosphine-containing TADF compound according to claim 7, characterized in that, The organic electroluminescent device includes a cathode, an anode, and an organic thin film layer sandwiched between the cathode and the anode. The organic thin film layer contains a light-emitting layer, and at least one layer of the organic thin film layer contains at least one of the phosphine-containing TADF compounds.

9. The application of the phosphine-containing TADF compound according to claim 8, characterized in that, The organic thin film layer has ≥1 light-emitting layer, and the light-emitting layer contains the phosphine-containing TADF compound.

10. The application of the phosphine-containing TADF compound according to claim 8, characterized in that, The phosphine-containing TADF compound is the main material of the light-emitting layer.

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