A six-membered and seven-membered boron-nitrogen heterocyclic derivative based on heavy atom fusion donors, its preparation method and application

Abstract

This invention belongs to the field of organic optoelectronic material preparation and application, specifically a six- or seven-membered boron-nitrogen heterocyclic derivative based on a heavy atom fusion donor, its preparation method, and its application. It possesses a structure as described in at least one of the general formulas A-1, A-2, B-1, and B-2. This invention significantly enhances the reverse intersystem crossing rate of the material based on the heavy atom effect. The unique fusion donor effect provides finely tunable electron-donating capability, enabling wide-range control of the emission wavelength and narrowing of the half-peak width of the heavy atom material. Applying such organic light-emitting molecules as luminescent materials or sensitizers in the luminescent layer structure of organic light-emitting diode (OLED) devices allows for controllable adjustment of the wavelength range from 450 nm to 490 nm, resulting in deep blue and blue-green OLED devices with high device efficiency and color purity.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic material preparation technology, specifically relating to a six-membered and seven-membered boron-nitrogen heterocyclic derivative based on a heavy atom fusion donor, its preparation method, and its application. Background Technology

[0002] With the continuous development of display technology, organic light-emitting diode (OLED) technology has gradually gained attention due to its outstanding advantages such as self-emission, fast response speed, and flexibility. Meanwhile, with the continuous development of OLED-related technologies and the increasing demands of consumers for light and color purity, thermally activated delayed fluorescence (TADF) emitter design strategies based on multiple resonance (MR) framework peripheral modification and fusion framework extension have been widely developed. In addition, in device structure design, TADF or phosphorescent materials are often used as sensitizers to increase exciton utilization channels, thereby reducing the annihilation process of triplet excitons and achieving efficient exciton utilization.

[0003] With the continuous development of OLED technology, the OLED display industry now places higher demands on resolution, color purity, device power consumption, and device lifespan. However, compared to conventional TADF emitters, MR-TADF emitters typically exhibit a relatively small reverse gap cross-pass velocity (k). RISC ), usually around 10 2 ~10 4 s -1 This results in a generally longer delayed fluorescence lifetime, and at high concentrations, triplet exciton annihilation is prone to occur, leading to a severe efficiency roll-off and poor luminescence performance in narrow-band light-emitting devices. Although adding heavy atoms (oxygen, sulfur, selenium, tellurium, etc.) to MR-TADF can effectively increase its kJ / kJ / kE ratio... RISC However, the introduction of heavy atoms inevitably causes MR-TADF materials to lose their narrow emission characteristics and result in a redshift in light color. To date, heavy-atom blue MR-TADF materials with narrow half-maximum width at half-maximum (WHM) characteristics remain extremely rare. Furthermore, almost all boron-nitrogen-based MR-TADF materials inherit the initial trigonene structure, greatly limiting the diversity of molecular design strategies. Therefore, OLED heavy-atom blue emitting materials and sensitizers require further development and expansion. Summary of the Invention

[0004] The purpose of this invention is to provide a hexa- and hexa-boron-nitrogen heterocyclic derivative based on a heavy atom fusion donor, its preparation method, and its application. Based on the heavy atom effect, the reverse intersystem crossing rate of the material can be significantly improved. The unique fusion donor effect has a finely tunable electron-donating capability, which can achieve a wide range of control over the emission wavelength and narrowing of the half-peak width of the heavy atom material.

[0005] To achieve the above objectives, according to one aspect of the present invention, a six-membered and seven-membered boron-nitrogen heterocyclic derivative based on a heavy atom fusion donor is provided, the general structural formula of which is shown in formulas A-1, A-2, B-1, and B-2:

[0006]

[0007] R1, R2, and R3 are each independently selected from hydrogen, deuterium, methyl, tert-butyl, aromatic amine groups with 6-24 carbon atoms or their derivatives, and aromatic amine heterocyclic groups with 12-24 carbon atoms or their derivatives.

[0008] Ar is selected from any one of hydrogen, deuterium, methyl, monophenyl groups, biphenyl groups, naphthyl groups, anthracene groups, carbazole groups, phenylamino groups, acridine groups, phenoxazine groups, phenothiazine groups, and aziridine groups;

[0009] X is selected from any one of carbon, oxygen, sulfur, selenium, and tellurium atoms.

[0010] Preferably, R1, R2, and R3 are each independently selected from any one of hydrogen, deuterium, methyl, tert-butyl, diphenylamino, carbazole, phenthiazinyl, phenoxazinyl, 9,10-dihydroacridinyl, 9,9-diphenylacridinyl, 9,9-dimethylacridinyl, diphenylamino derivatives, carbazole derivatives, 9,10-dihydroacridinyl derivatives, 9,9-diphenylacridinyl derivatives, or 9,9-dimethylacridinyl derivatives.

[0011] Preferably, Ar is selected from any one of hydrogen, deuterium, methyl, monobenzene groups or their derivatives, biphenyl groups or their derivatives, naphthyl groups or their derivatives, anthracene groups or their derivatives, carbazole groups or their derivatives, phenylamino groups or their derivatives, acridine groups or their derivatives, phenoxazine groups or their derivatives, phenothiazine groups or their derivatives, and azine groups or their derivatives.

[0012] More preferably, the structure of the boron-nitrogen heterocyclic derivative is selected from one of the following structural formulas, wherein general formula A-1 includes a-1 to a-20, general formula A-2 includes a-21 to a-40, general formula B-1 includes b-1 to b-16, and general formula B-2 includes b-17 to b-84:

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019] According to another aspect of the present invention, the present invention provides a method for preparing compounds referred to by general formula A-1, the preparation process of which is as follows:

[0020]

[0021] The preparation steps are as follows:

[0022] (1) Compound 1, Compound 2, benzylacetone dipalladium (Pd2(dba)3), tri-tert-butylphosphine tetrafluoroborate (t-Bu3PHBF4), sodium tert-butoxide (tBuONa) and dry toluene were added to a container and heated to 110-130℃ under nitrogen atmosphere and stirred for 8-20 h. After the reaction was complete, the mixture was cooled to room temperature. The organic layer was collected by washing with dichloromethane and water, dried and concentrated, and then purified by column chromatography. The crude product was further recrystallized with dichloromethane and methanol to obtain Compound 3.

[0023] The molar ratio of compound 1, compound 2, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, and sodium tert-butoxide is (45-47):(49-51):(0.9-1):(1.7-1.9):(130-140); the mass-to-volume ratio of compound 1 to toluene is 1 g:(9-11) mL.

[0024] (2) Compound 4, compound 5, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide, and dried toluene were added to a container and heated to 110-130°C under nitrogen atmosphere and stirred for 8-20 hours. After the reaction was complete, the mixture was cooled to room temperature. The organic layer was then collected by washing with dichloromethane and water, dried, concentrated, and preliminarily purified by column chromatography. The crude product was further recrystallized from dichloromethane and methanol to obtain compound 6. (The reaction ratio in step 2 is the same as in step (1), except that compounds 1 and 2 are replaced with compounds 4 and 5, respectively.)

[0025] (3) Compound 3, Compound 6, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide, and dried toluene were added to a container and heated to 85-95℃ under nitrogen atmosphere and stirred for 8-20 hours. After the reaction was complete, the mixture was cooled to room temperature. The organic layer was then collected by washing with dichloromethane and water, dried, concentrated, and preliminarily purified by column chromatography. The crude product was further recrystallized with dichloromethane and methanol to obtain Compound 7. The amount of benzylacetone dipalladium was 3-6% of the molar amount of Compound 6. The molar ratio of Compound 6, tri-tert-butylphosphine tetrafluoroborate, and sodium tert-butoxide was (45-47):(1.7-1.9):(130-140).

[0026] (4) After pre-drying compound 7 under vacuum, dissolve it in o-dichlorobenzene, remove the air, and then add boron tribromide dropwise in a nitrogen atmosphere. Heat the mixture to 170-190℃ and stir under reflux for 20-30 hours. After the reaction is complete, cool it to -5 to 5℃ (preferably 0℃), add N,N-diisopropylethylamine (DIPEA), and then stir the mixture at -5 to 5℃ for 1-3 hours. After the reaction is complete, remove o-dichlorobenzene by vacuum distillation, collect the concentrated mother liquor, and perform preliminary purification by column chromatography (using cyclohexane as the eluent). The crude product is further recrystallized from toluene and methanol to obtain a pale yellow solid powder, which is the compound referred to by general formula A-1.

[0027] The ratio of compound 7, boron tribromide, and N,N-diisopropylethylamine is 10 g: (3-4.5) mL: (48-55) mL.

[0028] The preparation steps of the compound referred to by general formula A-2 differ from those of A-1 in that the changes in reaction temperature and catalyst equivalent in step (3) will produce different compounds 7. Specifically, the reaction temperature is changed to 105-115℃, and the catalyst equivalent is 18-22% of the molar amount of compound 6.

[0029] The preparation steps of the compound referred to by general formula B-1 differ from those of A-1 in that compound 5 introduces a heavy atom group X (O, S, Se, Te):

[0030] The preparation steps of the compound referred to by general formula B-2 differ from those of A-2 in that heavy atomic groups X (O, S, Se, Te) are introduced into compound 5.

[0031] According to another aspect of the invention, the invention provides the application of the boron-nitrogen heterocyclic compounds based on heavy atom fusion donors in organic electroluminescent devices.

[0032] As a further preferred embodiment of the present invention, the hexa- and heptagonal boron-nitrogen heterocyclic derivatives based on heavy atom fusion donors are mainly used as guest light-emitting materials and sensitizer light-emitting materials in organic electroluminescent devices.

[0033] As a further preferred embodiment of the present invention, the organic electroluminescent device comprises, from top to bottom, an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode; the light-emitting layer comprises the hexa- and hexa-boron-nitrogen heterocyclic derivative.

[0034] Preferably, an exciton blocking layer is further provided between the hole transport layer and the light-emitting layer, and between the light-emitting layer and the electron transport layer.

[0035] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0036] 1. The hexa- and hexa-boron-nitrogen heterocyclic derivatives based on heavy atom fusion donors provided by this invention involve fusing different types of single donor groups with heavy atom-containing groups to form novel fused heavy atom donors with large volume, large steric hindrance, and strong rigidity. These fused heavy atom donors are then introduced into the resonance core of MR-TADF luminescent molecules, thereby obtaining hexa- and hexa-boron-nitrogen heterocyclic derivatives based on heavy atom fusion donors. This invention leverages the heavy atom effect to significantly enhance the reverse intersystem crossing rate of materials. The unique fusion donor effect provides finely tunable electron-donating capabilities, enabling wide-range control of emission wavelength and narrowing of the half-peak width of heavy atom materials. Applying such organic luminescent molecules as luminescent materials or sensitizers in the luminescent layer structure of organic light-emitting diode (OLED) devices allows for controllable adjustment of the wavelength range from 450nm to 490nm, resulting in deep blue and blue-green OLED devices with high device efficiency and color purity.

[0037] 2. This invention preferably uses a hexa- and heptagonal fused donor type boron-nitrogen heterocyclic MR-TADF emitter, breaking the initial trigonelline structure and further expanding the existing blue light boron-nitrogen MR-TADF system. It has a significant advantage in maintaining blue light emission. At the same time, based on the different electron-donating capabilities and different numbers of heavy atoms of the fused donor, a wide range of emission wavelengths can be controlled, covering the blue light field. This greatly enriches the diversity of molecular design strategies, which will be conducive to the further development of blue light materials and has great scientific and technological value and commercial application prospects.

[0038] 3. The hexa- and heptagonal boron-nitrogen heterocyclic derivatives based on heavy atom fusion donors described in this invention have heavy atoms incorporated into the donor rather than directly fused into the parent nucleus. This helps reduce molecular vibrational relaxation and ensures narrow emission of heavy atom MR-TADF. The half-width at half-maximum (WHM) is generally below 50 nm, making it a very rare narrow WHM heavy atom MR-TADF blue light material.

[0039] 4. In addition, the introduction of heavy atoms such as O, S, Se, and Te into the MR framework can enhance the spin-orbit coupling (SOC) between T1 and S1, increase the reverse intersystem crossing rate of triplet excitons, and reduce the annihilation process associated with triplet excitons. Therefore, the heavy atom effect in hexa- and hexa-boron-nitrogen heterocyclic derivatives can be gradually enhanced, and they can be used as light-emitting guests in OLED devices, which will help improve the efficiency and stability of the devices.

[0040] 5. The introduction of heavy atoms enhances the state of charge (SOC). In device structures, this will be beneficial as a sensitizer for blue OLED light-emitting materials, enabling high efficiency. Energy transfer allows for full utilization of triplet excitons, giving it an advantage in the development of novel MR-TADF sensitizer materials. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of an electroluminescent device;

[0042] Figure 2 Thermogravimetric analysis curves for synthesis examples a-1, a-41, b-33, and b-45;

[0043] Figure 3 The brightness-external quantum efficiency curves for device embodiments 1, 2, 19, and 20 are shown.

[0044] Figure 4 This is the general structural formula of the hexa- and hexa-boron-nitrogen heterocyclic derivatives based on heavy atom fusion donors in this invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0046] The following is an example:

[0047] Synthesis Example 1: The above-mentioned compound a-1 of the present invention conforms to the general formula A-1 and can be synthesized by the following method:

[0048]

[0049] (1) 1-Chloro-10H-phenoxazine (10 g, 45.94 mmol), aniline (4.66 g, 50.00 mmol), benzylacetone dipalladium (0.85 g, 0.919 mmol), tri-tert-butylphosphine tetrafluoroborate (0.54 g, 1.838 mmol), sodium tert-butoxide (13.24 g, 137.82 mmol), and dry toluene (100 ml) were added to a 500 ml three-necked flask. The mixture was bubbled with nitrogen for 15 minutes, and then heated to 120 °C under nitrogen and stirred for 12 hours. After the reaction was complete, it was cooled to room temperature. The organic layer was collected by washing with dichloromethane and water, dried and concentrated, and preliminarily purified by column chromatography. The crude product was further recrystallized from dichloromethane and methanol to obtain a white solid powder, 9.18 g, with a yield of 90.99%.

[0050] (2) Same as step (1), except that the reaction raw materials are changed to m-bromochlorobenzene (10g, 52.23mmol) and diphenylamine (9.31g, 55mmol). The catalyst, ligand and base are added in the proportions in (1) (all refer to the same molar ratio relative to m-bromochlorobenzene as the same molar ratio relative to 1-chloro-10H-phenoxazine in step 1). The product is initially purified by column chromatography. The crude product is further recrystallized from dichloromethane and methanol to obtain a white solid powder, 11.82g, with a yield of 82.64%.

[0051] (3) In the same step (1), the product of (1) (9g, 32.80mmol), the product of (2) (7.30g, 32mmol), the catalyst benzylacetone dipalladium (1.6mmol), the ligand tri-tert-butylphosphine tetrafluoroborate (1.28mmol), and the base sodium tert-butoxide (96mmol) were added to a flask. The reflux temperature was 90℃. The mixture was initially purified by column chromatography and recrystallized to obtain 14.17g of white solid powder compound, with a yield of 83.49%.

[0052] (4) The white solid powder compound (10 g, 19.32 mmol) was dried under vacuum and dissolved in 200 ml of o-dichlorobenzene. It was sonicated to dissolve completely, and the air was repeatedly evacuated by an oil pump. Then, in a nitrogen atmosphere, 3.72 ml of boron tribromide was slowly added dropwise below 25 °C. The mixture was heated to 180 °C and stirred under reflux for 24 hours. After the reaction was complete, it was cooled to 0 °C, and 50.47 ml of N,N-diisopropylethylamine (DIPEA) was added. The mixture was then stirred at 0 °C for 2 hours. After the reaction was complete, o-dichlorobenzene was removed by vacuum distillation. The concentrated mother liquor was collected and preliminarily purified by column chromatography (the eluent was cyclohexane). The crude product was further recrystallized from toluene and methanol to obtain 4.21 g of pale yellow solid powder, with a yield of 41.52%.

[0053] High-resolution mass spectrometry (APCI-MS) (m / z): Theoretical molecular weight: 525.42; Measured value: 525.37. Elemental analysis results: Theoretical values: C: 82.30%; H: 4.60%; B: 2.06%; N: 8.00%; O: 3.05%. Experimental values: C: 82.35%; H: 4.61%; B: 2.01%; N: 8.01%; O: 3.03. NMR... 1 H NMR(500MHz,Chloroform-d)δ7.44-7.30(m,4H),7.34-7.23(m,1H),7.18(td,J=7.9,1 .5Hz,1H),7.14-6.96(m,5H),6.86(d,J=7.0Hz,1H),6.71(ddd,J=8.4,4.0,1.3Hz,1H).

[0054] Synthesis Example 2: The above-mentioned compound a-21 of the present invention, conforming to general formula A-2, can be synthesized by the following method:

[0055]

[0056] This embodiment is basically the same as the first three steps of the synthesis embodiment 1. The difference is that the changes in reaction temperature (reflux temperature is adjusted to 110°C) and catalyst equivalent (6.4 mmol) in step (3) have different tendencies to produce the two products in the third step of embodiment 1 and 2.

[0057] High-resolution mass spectrometry (APCI-MS) (m / z): Theoretical molecular weight: 525.42; Measured value: 525.37. Elemental analysis results: Theoretical values: C: 82.30%; H: 4.60%; B: 2.06%; N: 8.00%; O: 3.05%. Experimental values: C: 82.35%; H: 4.61%; B: 2.01%; N: 8.01%; O: 3.03. NMR... 1¹H NMR (500MHz, Chloroform-d) δ 7.45 (dd, J = 8.0, 1.4Hz, 1H), 7.37–7.22 (m, 6H), 7.22–7.05 (m, 10H), 7.05–6.97 (m, 1H), 6.88 (dddd, J = 7.5, 2.3, 1.2Hz, 3H), 6.83 (dd, J = 7.1, 1.1Hz, 1H), 6.75 (dd, J = 8.4, 1.1Hz, 1H). The mass spectrometry, elemental analysis, and ¹H NMR results confirm that the product structure is correct and is the target compound a-21.

[0058] Synthesis Example 3: The above-mentioned compound a-33 of the present invention conforms to general formula A-2 and can be synthesized by the following method:

[0059]

[0060] This example is basically the same as Synthesis Example 2, except that diphenylamine is replaced with an equal amount of bis(4-(tert-butyl)phenyl)amine, while all other conditions remain unchanged. High-resolution mass spectrometry (APCI-MS) (m / z): Theoretical molecular weight is 637.63, measured value: 637.57. Elemental analysis results: Theoretical values: C: 82.88%; H: 6.32%; B: 1.70%; N: 6.59%; O: 2.51%. Experimental values: C: 82.85%; H: 6.34%; B: 1.71%; N: 6.57%; O: 2.49. NMR... 1 ¹H NMR (500MHz, Chloroform-d) δ 7.35–7.26 (m, 6H), 7.26–7.13 (m, 5H), 7.13–7.06 (m, 3H), 7.06–6.93 (m, 4H), 6.91–6.81 (m, 4H), 1.34 (d, J = 0.7 Hz, 18H). Mass spectrometry, elemental analysis, and ¹H NMR results confirm that the product structure is correct and is the target compound a-33.

[0061] Synthesis Example 4: The above-mentioned compound b-1 of the present invention conforms to the general formula B-1 and can be synthesized by the following method:

[0062]

[0063] This example is essentially the same as Synthesis Example 1, except that diphenylamine is replaced with an equal amount of phenoxazine, while all other conditions remain unchanged. A final yield of 4.46 g of yellow solid was obtained. APCI-MS (m / z): 539.38, theoretical molecular weight 539.40. Elemental analysis results: Theoretical values: C: 80.16%; H: 4.11%; B: 2.00%; N: 7.79%; O: 5.93%. Experimental values: C: 80.18%; H: 4.13%; B: 2.00%; N: 7.77%; O: 5.91%. NMR... 1 ¹H NMR (500MHz, Chloroform-d) δ 7.50 (dd, J = 7.1, 1.5Hz, 1H), 7.44–7.34 (m, 4H), 7.37–7.30 (m, 2H), 7.25–7.18 (m, 3H), 7.20–7.14 (m, 1H), 7.14–7.07 (m, 3H), 7.02–6.94 (m, 3H), 6.94 (dd, J = 7.0, 1.2Hz, 1H), 6.84 (ddd, J = 18.7, 7.0, 1.5Hz, 2H), 6.71 (ddd, J = 8.4, 4.0, 1.3Hz, 2H). The mass spectrometry, elemental analysis, and ¹H NMR results confirm that the product structure is correct and is the target compound b-1.

[0064] Synthesis Example 5: The above-mentioned compound b-17 of the present invention conforms to the general formula B-2 and can be synthesized by the following method:

[0065]

[0066] This example is basically the same as Synthesis Example 2, except that diphenylamine is replaced with an equal amount of phenoxazine, while other conditions remain unchanged. A final yield of 4.62 g of yellow solid was obtained. APCI-MS (m / z): 539.38, theoretical molecular weight 539.40. Elemental analysis results: Theoretical values: C: 80.16%; H: 4.11%; B: 2.00%; N: 7.79%; O: 5.93%. Experimental values: C: 80.18%; H: 4.13%; B: 2.00%; N: 7.77%; O: 5.91%. NMR... 1¹H NMR (500MHz, Chloroform-d) δ 7.41 (dd, J=7.1, 1.5Hz, 1H), 7.33–7.22 (m, 5H), 7.22–7.06 (m, 8H), 7.01 (tt, J=7.4, 1.5Hz, 1H), 6.91–6.88 (m, 3H), 6.88–6.82 (m, 2H), 6.77–6.69 (m, 2H). Mass spectrometry, elemental analysis, and ¹H NMR results confirm that the product structure is correct and is the target compound b-17.

[0067] Synthesis Example 6: The above-mentioned compound b-25 of the present invention conforms to the general formula B-2 and can be synthesized by the following method:

[0068]

[0069] This example is basically the same as Synthesis Example 3, except that the phenoxazine is replaced with an equal amount of phenselenazine, while the other conditions remain unchanged. A final yield of 3.28 g of yellow solid was obtained, with a yield of 32.43%. APCI-MS (m / z): 602.45, theoretical molecular weight 602.37. Elemental analysis results: Theoretical values: C: 71.78%; H: 3.68%; B: 1.79%; N: 6.98%; O: 2.66%; Se: 13.11. Experimental values: C: 71.75%; H: 3.66%; B: 1.78%; N: 6.96%; O: 2.67%; Se: 13.12. NMR... 1 ¹H NMR (500MHz, Chloroform-d) δ 7.82–7.73 (m, 2H), 7.44 (dd, J = 7.3, 1.1 Hz, 1H), 7.39–7.34 (m, 2H), 7.31 (t, J = 7.1 Hz, 1H), 7.27–7.22 (m, 2H), 7.22–7.06 (m, 7H), 7.05–6.97 (m, 2H), 6.89–6.86 (m, 3H), 6.86–6.82 (m, 1H), 6.72 (dd, J = 8.4, 1.3 Hz, 1H). The mass spectrometry, elemental analysis, and ¹H NMR results confirm that the product structure is correct and is the target compound b-25.

[0070] Synthesis Example 7: The above-mentioned compound b-65 of the present invention conforms to the general formula B-2 and can be synthesized by the following method:

[0071]

[0072] (1) Same as step (1) of Example 2;

[0073] (2) 1,3-Dibromo-5-chlorobenzene (10 g, 36.99 mmol), phenselenidine (9.85 g, 40 mmol), tris(dibenzylacetone)palladium (0.68 g, 0.74 mmol), DPEphos (0.43 g, 1.48 mmol), sodium tert-butoxide (10.65 g, 111 mmol), and dry toluene (200 ml) were added to a 500 ml three-necked flask. The mixture was bubbled with nitrogen for 15 minutes, and then heated to 120 °C under nitrogen and stirred for 12 hours. After the reaction was complete, it was cooled to room temperature. The organic layer was collected by washing with dichloromethane and water, dried and concentrated, and preliminarily purified by column chromatography. The crude product was further recrystallized from dichloromethane and methanol to obtain a white solid powder, 12.14 g, with a yield of 75.36%.

[0074] (3) Same as step (2), except that the reactants are replaced with the product of (1) (9g, 32.80mmol) and the product of (2) (13.94g, 32mmol), and the catalyst, ligand and base are added in the same proportion as in step (2). After preliminary purification by column chromatography and recrystallization, 14.08g of white solid powder compound is obtained, with a yield of 69.98%.

[0075] (4) Same as step (3), except that the reactants are replaced with the product of (3) (10g, 15.89mmol) and diphenylamine (2.71g, 16mmol), and added with catalyst, ligand and base in the same proportion as in step (2). After preliminary purification by column chromatography and recrystallization, 11.55g of white solid powder compound is obtained, with a yield of 95.42%.

[0076] (5) Same as step (4) of Example 2, except that the compound in step (4) of Example 2 is replaced with the product (10g, 36.45mmol) in step (4) of this Example, and all other conditions remain unchanged. A yellow solid of 4.01g was finally obtained, with a yield of 39.72%.

[0077] APCI-MS (m / z): 769.58, theoretical molecular weight 769.49. Elemental analysis results: Theoretical values: C: 74.91%; H: 4.06%; B: 1.40%; N: 7.28%; O: 2.08%; Se: 10.26%. Experimental values: C: 74.90%; H: 4.08%; B: 1.37%; N: 7.26%; O: 2.09%; Se: 10.29%. NMR. 1¹H NMR (500MHz, Chloroform-d) δ 7.82–7.73 (m, 2H), 7.44 (dd, J = 7.3, 1.1 Hz, 1H), 7.39–7.32 (m, 2H), 7.32–7.22 (m, 6H), 7.22–7.18 (m, 2H), 7.18–7.07 (m, 10H), 7.07–6.97 (m, 4H), 6.86 (ddd, J = 13.6, 7.5, 1.0 Hz, 2H), 6.72 (dd, J = 8.4, 1.3 Hz, 1H), 6.68–6.62 (m, 2H). The mass spectrometry and elemental analysis results confirm that the product structure is correct and is the target compound b-65.

[0078] These hexa- and hexa-boron-nitrogen heterocyclic derivatives based on heavy atom fusion donors are particularly suitable for use as guest luminescent materials and sensitizers in devices. The device fabrication process can be as follows: an ITO (indium tin oxide) glass substrate is successively ultrasonically cleaned for 60 minutes in ITO cleaning agent, isopropanol, acetone, ethanol, and deionized water. After drying with nitrogen, it is dried in an oven at 120°C for 2 hours. Before device fabrication, the ITO glass substrate was surface-treated with oxygen plasma for 10 minutes, then transferred to an organic vacuum chamber for evaporation of organic functional layer materials. A 10 nm thick hole injection material, HAT-CN (2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene), was prepared by vacuum evaporation. Next, a 50 nm thick hole transport material, TAPC (4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline]), was deposited. Then, a 10 nm thick electron blocking layer, mCBP (3,3-di(carbazolyl)biphenyl), was vacuum-evaporated onto this hole transport layer. Following this, a 20 nm thick light-emitting layer was deposited, and then a 40 nm thick electron transport material, TmPyPB (1,3,5-tris(3-pyridyl-3-phenyl)benzene), was deposited. Finally, a 1 nm thick LiF layer and a 10 nm thick Al layer were deposited. A schematic diagram of the device structure is shown below. Figure 1 As shown, in practical applications, the bandgap (emission color) of the hexa- and hexa-boron-nitrogen heterocyclic derivatives based on heavy atom fusion donors according to the present invention can be used selectively or not. In addition, the transport layer material system can be screened according to the energy level matching principle and the electron-hole carrier balance principle to optimize the film thickness, the luminescent layer thickness and the host-guest doping concentration, etc.

[0079] The specific device structure of this invention embodiment is as follows:

[0080] (1) When a hexa- or hexa- or boron- or nitrogen-based heterocyclic derivative of a heavy atom fusion donor is used as a guest light-emitting material (Dopant), the device structure is as follows:

[0081] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:Dopant(20nm,3wt%) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0082] (2) When the fused donor hexa- and hexa-boron-nitrogen heterocyclic derivative is used as the sensitizer, the device structure is as follows:

[0083] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%PhDMAC-BN(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0084] The following are examples of the device (each organic functional layer has been optimized):

[0085] Device Comparison Example 1:

[0086] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:Dopant(20nm,3wt%) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0087] The guest light-emitting material (Dopant) is a conventional MR-TADF single-boron compound PhDMAC-BN. This device exhibits an electroluminescence peak wavelength of 480 nm, a full width at half maximum (FWHM) of 34 nm, and a maximum external quantum efficiency (EQE). max The efficiency was 21.6%, the drive voltage was 3.4V, and the device lifetime was LT. 95 For 77 hours @ initial brightness 2000 cd / m² 2 .

[0088] Device Example 1:

[0089] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:Dopant(20nm,3wt%) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0090] The guest light-emitting material (Dopant) of the emitting layer is the fused donor compound a-1 described in this invention. The device has an electroluminescence peak wavelength of 471 nm, a full width at half maximum (FWHM) of 27 nm, and a maximum external quantum efficiency (EQE). max The percentage is 29.7%, the drive voltage is 3.4V, and the device lifetime is LT. 95For 91 hours @ initial brightness 2000 cd / m² 2 .

[0091] Device Example 2:

[0092] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:Dopant(20nm,3wt%) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0093] The guest light-emitting material (Dopant) of the emitting layer is the fused donor compound a-5 described in this invention. The device exhibits an electroluminescence peak wavelength of 468 nm, a full width at half maximum (FWHM) of 24 nm, and a maximum external quantum efficiency (EQE). max The efficiency is 30.5%, the drive voltage is 3.4V, and the device lifetime is LT. 95 For 94 hours @ initial brightness 2000 cd / m² 2 .

[0094] Device Example 3:

[0095] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:Dopant(20nm,3wt%) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0096] The guest light-emitting material (Dopant) of the light-emitting layer is the fused donor compound a-17 described in this invention. The device has an electroluminescence peak wavelength of 471 nm, a full width at half maximum (FWHM) of 27 nm, and a maximum external quantum efficiency (EQE). max The efficiency is 31.4%, the drive voltage is 3.5V, and the device lifetime is LT. 95 For 91 hours @ initial brightness 2000 cd / m² 2 .

[0097] Device Example 4:

[0098] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:Dopant(20nm,3wt%) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0099] The guest light-emitting material (Dopant) of the light-emitting layer is the fused donor compound a-25 described in this invention. The device exhibits an electroluminescence peak wavelength of 469 nm, a full width at half maximum (FWHM) of 27 nm, and a maximum external quantum efficiency (EQE). maxThe efficiency is 31.2%, the drive voltage is 3.5V, and the device lifetime is LT. 95 105 hours @ initial brightness 2000 cd / m² 2 .

[0100] Device Example 5:

[0101] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:Dopant(20nm,3wt%) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0102] The guest light-emitting material (Dopant) of the light-emitting layer is the fused donor compound a-33 described in this invention. The device has an electroluminescence peak wavelength of 473 nm, a full width at half maximum (FWHM) of 26 nm, and a maximum external quantum efficiency (EQE). max The efficiency was 32.9%, the drive voltage was 3.4V, and the device lifetime was LT. 95 For 96 hours @ initial brightness 2000 cd / m² 2 .

[0103] Device Example 6:

[0104] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:Dopant(20nm,3wt%) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0105] The guest light-emitting material (Dopant) of the light-emitting layer is the fused donor compound a-40 described in this invention. The device has an electroluminescence peak wavelength of 476 nm, a full width at half maximum (FWHM) of 30 nm, and a maximum external quantum efficiency (EQE). max The efficiency is 32.1%, the drive voltage is 3.4V, and the device lifetime is LT. 95 For 100 hours @ initial brightness 2000 cd / m² 2 .

[0106] Device Example 7:

[0107] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:Dopant(20nm,3wt%) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0108] The guest light-emitting material (Dopant) of the emitting layer is the fused donor compound b-5 described in this invention. The device exhibits an electroluminescence peak wavelength of 497 nm, a full width at half maximum (FWHM) of 35 nm, and a maximum external quantum efficiency (EQE). max The efficiency is 31.5%, the drive voltage is 3.4V, and the device lifetime is LT. 95 For 85 hours @ initial brightness 4000 cd / m² 2 .

[0109] Device Example 8:

[0110] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:Dopant(20nm,3wt%) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0111] The guest light-emitting material (Dopant) of the light-emitting layer is the fused donor compound b-30 described in this invention. This device has an electroluminescence peak wavelength of 485 nm, a full width at half maximum (FWHM) of 32 nm, and a maximum external quantum efficiency (EQE). max The efficiency is 33.5%, the drive voltage is 3.4V, and the device lifetime is LT. 95 For 91 hours @ initial brightness 2000 cd / m² 2 .

[0112] Device Example 9:

[0113] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:Dopant(20nm,3wt%) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0114] The guest light-emitting material (Dopant) of the emitting layer is the fused donor compound b-37 described in this invention. This device has an electroluminescence peak wavelength of 465 nm, a full width at half maximum (FWHM) of 25 nm, and a maximum external quantum efficiency (EQE). max The efficiency was 33.8%, the drive voltage was 3.3V, and the device lifetime was LT. 95 For 89 hours @ initial brightness 2000 cd / m² 2 .

[0115] Device Example 10:

[0116] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:Dopant(20nm,3wt%) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0117] The guest light-emitting material (Dopant) of the emitting layer is the fused donor compound b-39 described in this invention. This device has an electroluminescence peak wavelength of 470 nm, a full width at half maximum (FWHM) of 27 nm, a maximum external quantum efficiency (EQEmax) of 34.8%, a driving voltage of 3.5 V, and a device lifetime of LT. 95 For 92 hours @ initial brightness 2000 cd / m² 2 .

[0118] Device Example 11:

[0119] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%PhDMAC-BN(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0120] The sensitizer material is the fusion donor compound a-1 described in this invention, and the luminescent guest is PhDMAC-BN. This device has an electroluminescence peak wavelength of 480 nm, a full width at half maximum (FWHM) of 34 nm, and a maximum external quantum efficiency (EQE). max The accuracy rate is 30.9%, the drive voltage is 3.4V, and the device lifetime is LT. 95 For 91 hours @ initial brightness 6000 cd / m² 2 .

[0121] Device Example 12:

[0122] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%PhDMAC-BN(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0123] The sensitizer material is the fusion donor compound a-5 described in this invention, and the luminescent guest is PhDMAC-BN. This device has an electroluminescence peak wavelength of 480 nm, a full width at half maximum (FWHM) of 34 nm, and a maximum external quantum efficiency (EQE). max The efficiency was 31.2%, the drive voltage was 3.4V, and the device lifetime was LT. 95 For 92 hours @ initial brightness 6000 cd / m² 2 .

[0124] Device Example 13:

[0125] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%PhDMAC-BN(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0126] The sensitizer material is the fusion donor compound a-17 described in this invention, and the luminescent guest is PhDMAC-BN. This device has an electroluminescence peak wavelength of 480 nm, a full width at half maximum (FWHM) of 34 nm, and a maximum external quantum efficiency (EQE). max The efficiency was 31.8%, the drive voltage was 3.4V, and the device lifetime was LT. 95 For 94 hours @ initial brightness 6000 cd / m² 2 .

[0127] Device Example 14:

[0128] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%PhDMAC-BN(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0129] The sensitizer material is the fusion donor compound a-25 described in this invention, and the luminescent guest is PhDMAC-BN. This device has an electroluminescence peak wavelength of 480 nm, a full width at half maximum (FWHM) of 34 nm, and a maximum external quantum efficiency (EQE). max The efficiency is 32.4%, the drive voltage is 3.4V, and the device lifetime is LT. 95 For 100 hours @ initial brightness 6000 cd / m² 2 .

[0130] Device Example 15:

[0131] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%PhDMAC-BN(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0132] The sensitizer material is the fusion donor compound a-33 described in this invention, and the luminescent guest is PhDMAC-BN. This device has an electroluminescence peak wavelength of 480 nm, a full width at half maximum (FWHM) of 34 nm, and a maximum external quantum efficiency (EQE). maxThe efficiency is 32.6%, the drive voltage is 3.4V, and the device lifetime is LT. 95 For 99 hours @ initial brightness 6000 cd / m² 2 .

[0133] Device Example 16:

[0134] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%PhDMAC-BN(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0135] The sensitizer material is the fusion donor compound b-1 described in this invention. The device exhibits an electroluminescence peak wavelength of 480 nm, a full width at half maximum (FWHM) of 34 nm, a maximum external quantum efficiency (EQEmax) of 32.4%, a driving voltage of 3.4 V, and a device lifetime of LT. 95 103 hours @ initial brightness 6000 cd / m² 2 .

[0136] Device Example 17:

[0137] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%PhDMAC-BN(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0138] The sensitizer material is the fusion donor compound b-33 described in this invention. The device exhibits an electroluminescence peak wavelength of 480 nm, a full width at half maximum (FWHM) of 34 nm, a maximum external quantum efficiency (EQEmax) of 32.6%, a driving voltage of 3.4 V, and a device lifetime of LT. 95 For 89 hours @ initial brightness 6000 cd / m² 2 .

[0139] Device Example 18:

[0140] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%PhDMAC-BN(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0141] The sensitizer material is the fusion donor compound b-34 described in this invention. The device exhibits an electroluminescence peak wavelength of 480 nm, a full width at half maximum (FWHM) of 34 nm, a maximum external quantum efficiency (EQEmax) of 34.1%, a driving voltage of 3.4 V, and a device lifetime of LT. 95 For 96 hours @ initial brightness 6000 cd / m² 2 .

[0142] Device Example 19:

[0143] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%PhDMAC-BN(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0144] The sensitizer material is the fusion donor compound b-36 described in this invention. The device exhibits an electroluminescence peak wavelength of 480 nm, a full width at half maximum (FWHM) of 34 nm, a maximum external quantum efficiency (EQEmax) of 33.8%, a driving voltage of 3.4 V, and a device lifetime of LT. 95 For 90 hours @ initial brightness 6000 cd / m² 2 .

[0145] Device Example 20:

[0146] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%PhDMAC-BN(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0147] The guest light-emitting material (Dopant) of the light-emitting layer is the fused donor compound b-38 described in this invention. This device has an electroluminescence peak wavelength of 480 nm, a full width at half maximum (FWHM) of 34 nm, a maximum external quantum efficiency (EQEmax) of 34.8%, a driving voltage of 3.4 V, and a device lifetime of LT. 95 For 94 hours @ initial brightness 6000 cd / m² 2 .

[0148] Device Example 21:

[0149] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%Dopant(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0150] The sensitizer material for the luminescent layer is the fusion donor compound b-49 described in this invention, and the dopant material for the luminescent layer is the fusion donor compound a-1 described in this invention. This device has an electroluminescence peak wavelength of 471 nm, a full width at half maximum (FWHM) of 27 nm, and a maximum external quantum efficiency (EQE). max The efficiency is 30.5%, the drive voltage is 3.4V, and the device lifetime is LT. 95 103 hours @ initial brightness 8000 cd / m² 2 .

[0151] Device Example 22:

[0152] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%Dopant(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0153] The sensitizer material for the luminescent layer is the fusion donor compound b-49 described in this invention, and the dopant material for the luminescent layer is the fusion donor compound a-41 described in this invention. This device has an electroluminescence peak wavelength of 476 nm, a full width at half maximum (FWHM) of 30 nm, and a maximum external quantum efficiency (EQE). max The efficiency is 34.2%, the drive voltage is 3.4V, and the device lifetime is LT. 95 For 100 hours @ initial brightness 8000 cd / m² 2 .

[0154] Device Example 23:

[0155] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%Dopant(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0156] The sensitizer material for the luminescent layer is the fusion donor compound b-49 described in this invention, and the dopant material for the luminescent layer is the fusion donor compound b-5 described in this invention. This device has an electroluminescence peak wavelength of 497 nm, a full width at half maximum (FWHM) of 35 nm, and a maximum external quantum efficiency (EQE). max The accuracy rate is 33.9%, the drive voltage is 3.4V, and the device lifetime is LT. 95 For 85 hours @ initial brightness 8000 cd / m² 2 .

[0157] Device Example 24:

[0158] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%Dopant(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0159] The sensitizer material for the luminescent layer is the fusion donor compound b-49 described in this invention, and the dopant material for the luminescent layer is the fusion donor compound b-30 described in this invention. This device has an electroluminescence peak wavelength of 485 nm, a full width at half maximum (FWHM) of 32 nm, and a maximum external quantum efficiency (EQE). max The efficiency is 35.5%, the drive voltage is 3.4V, and the device lifetime is LT. 95 For 91 hours @ initial brightness 8000 cd / m² 2 .

[0160] Device Example 25:

[0161] ITO / HAT-CN(10nm) / TAPC(50nm) / mCBP(10nm) / mCBP:20wt%Sensitizer:x wt%Dopant(x=3) / TmPyPB(40nm) / LiF(1nm) / Al(100nm)

[0162] The sensitizer material for the luminescent layer is the fusion donor compound b-49 described in this invention, and the dopant material for the luminescent layer is the fusion donor compound b-39 described in this invention. This device has an electroluminescence peak wavelength of 470 nm, a full width at half maximum (FWHM) of 27 nm, and a maximum external quantum efficiency (EQE). max The efficiency was 36.8%, the drive voltage was 3.5V, and the device lifetime was LT. 95 For 92 hours @ initial brightness 8000 cd / m² 2 .

[0163] The above embodiments have verified that the compounds of the present invention achieve spectral modulation over a wide wavelength range while maintaining a narrow emission full width at half maximum (FWHM). Figure 2 The thermogravimetric curves of some molecules demonstrate that the six- or seven-membered boron-nitrogen heterocyclic derivatives of the heavy atom fusion donor possess excellent thermal stability, meeting industry requirements. Applying the compounds of this invention to OLED devices yielded excellent device performance. Figure 3 The brightness-external quantum efficiency curves of the device embodiment clearly demonstrate that the compound of the present invention possesses excellent electroluminescence performance and has great potential for industrial applications.

[0164] In summary, this invention addresses the problems of the single MR-TADF material system, the scarcity of heavy atom narrow-emission blue light materials, and the low utilization rate of triplet excitons. It provides a hexa- and seven-membered boron-nitrogen heterocyclic derivative based on a heavy atom fusion donor. By fusing different types of single donor groups with heavy atom-containing groups, a novel fused heavy atom donor with large volume, high steric hindrance, and strong rigidity is formed. This donor is then introduced into the resonant core of the MR-TADF luminescent molecule. Applying this type of organic luminescent molecule as a luminescent material or sensitizer in the luminescent layer structure of organic light-emitting diode (OLED) devices enables controllable adjustment of the wavelength range from 450nm to 490nm, resulting in deep blue and blue-green OLED devices with high device efficiency and color purity.

[0165] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A six- or seven-membered boron-nitrogen heterocyclic derivative based on a heavy atom fusion donor, characterized in that, This hexa- and heptagonal boron-nitrogen heterocyclic derivative based on heavy atom fusion donors has a structure as described in at least one of general formulas A-1, A-2, B-1, and B-2: R1, R2, and R3 are each independently selected from hydrogen, deuterium, methyl, tert-butyl, and phenyl. Ar is selected from any one of hydrogen, deuterium, methyl, monophenyl group, biphenyl group, naphthyl group, anthracene group, carbazole group, phenylamino group, acridine group, phenoxazine group, phenothiazine group, and azimine group; X represents a heavy atom, selected from any one of carbon, oxygen, sulfur, selenium, or tellurium atoms.

2. The hexa- and heptagonal boron-nitrogen heterocyclic derivative based on a heavy atom fusion donor as described in claim 1, characterized in that, R1, R2, and R3 are each independently selected from hydrogen, deuterium, methyl, and tert-butyl.

3. The six-membered and seven-membered boron-nitrogen heterocyclic derivative based on heavy atom fusion donors as described in claim 1, characterized in that: The structure of the boron-nitrogen heterocyclic derivative is selected from one of the following structural formulas, wherein general formula A-1 includes one of a-1 to a-20, general formula A-2 includes one of a-21 to a-40, general formula B-1 includes one of b-1 to b-16, and general formula B-2 includes one of b-17 to b-84: 。 4. A method for preparing a six-membered and seven-membered boron-nitrogen heterocyclic derivative based on a heavy atom fusion donor as described in claim 1, characterized in that, When the hexa- or hexa-boron-nitrogen heterocyclic derivative satisfies general formula A-1, the preparation process is as follows: The preparation steps are as follows: (1) Compound 1, Compound 2, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide and dry toluene were added to a container and heated to 110-130 °C under nitrogen atmosphere and stirred under reflux. After the reaction was complete, the mixture was cooled to room temperature, and the organic layer was extracted and collected. Compound 3 was then obtained by purification. (2) Compound 4, compound 5, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide and dry toluene were added to a container and heated to 110-130 °C under nitrogen atmosphere and stirred under reflux. After the reaction was complete, the mixture was cooled to room temperature, and the organic layer was extracted and collected. Compound 6 was then purified. (3) Compound 3, compound 6, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide, and dried toluene were added to a container and heated to 85-95 °C under nitrogen atmosphere with stirring. After the reaction was complete, the mixture was cooled to room temperature, and the organic layer was extracted and collected. The organic layer was then purified to obtain compound 7. The amount of benzylacetone dipalladium used was 3-6% of the molar amount of compound 6. (4) After drying compound 7 under vacuum, dissolve it in o-dichlorobenzene, remove the air, and then add boron tribromide dropwise in a nitrogen atmosphere. Heat the mixture to 170-190 °C and stir under reflux. After the reaction is complete, cool it to -5~5 °C and add N,N-diisopropylethylamine. Then keep the mixture at -5~5 °C and stir under reflux. After the reaction is complete, remove o-dichlorobenzene by vacuum distillation, collect the concentrated mother liquor, and purify it to obtain a pale yellow solid powder, which is the compound referred to by general formula A-1.

5. A method for preparing a six-membered and seven-membered boron-nitrogen heterocyclic derivative based on a heavy atom fusion donor as described in claim 1, characterized in that, When the hexa- or hexa-boron-nitrogen heterocyclic derivative satisfies general formula A-2, the preparation process is as follows: The preparation steps are as follows: (1) Compound 1, Compound 2, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide and dry toluene were added to a container and heated to 110-130 °C under nitrogen atmosphere and stirred under reflux. After the reaction was complete, the mixture was cooled to room temperature, and the organic layer was extracted and collected. Compound 3 was then obtained by purification. (2) Compound 4, compound 5, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide and dry toluene were added to a container and heated to 110-130 °C under nitrogen atmosphere and stirred under reflux. After the reaction was complete, the mixture was cooled to room temperature, and the organic layer was extracted and collected. Compound 6 was then purified. (3) Compound 3, compound 6, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide, and dried toluene were added to a container and heated to 105-115 °C under nitrogen atmosphere with stirring under reflux. After the reaction was complete, the mixture was cooled to room temperature, and the organic layer was extracted and collected. The organic layer was then purified to obtain compound 7. The amount of benzylacetone dipalladium used was 18-22% of the molar amount of compound 6. (4) After pre-drying compound 7 under vacuum, dissolve it in o-dichlorobenzene, remove the air, and then add boron tribromide dropwise in a nitrogen atmosphere. Heat the mixture to 170-190 °C and stir under reflux. After the reaction is complete, cool it to -5~5 °C, add N,N-diisopropylethylamine, and then stir the mixture at -5~5 °C. After the reaction is complete, remove o-dichlorobenzene by vacuum distillation, collect the concentrated mother liquor, and purify it to obtain a pale yellow solid powder, which is the compound referred to by general formula A-2.

6. A method for preparing a six-membered and seven-membered boron-nitrogen heterocyclic derivative based on a heavy atom fusion donor as described in claim 1, characterized in that, When the hexa- or hexa-boron-nitrogen heterocyclic derivative satisfies general formula B-1, the following steps are included: The preparation process is as follows: The preparation steps are as follows: (1) Compound 1, Compound 2, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide and dry toluene were added to a container and heated to 110-130 °C under nitrogen atmosphere and stirred under reflux. After the reaction was complete, the mixture was cooled to room temperature, and the organic layer was extracted and collected. Compound 3 was then obtained by purification. (2) Compound 4, compound 5, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide and dry toluene were added to a container and heated to 110-130 °C under nitrogen atmosphere and stirred under reflux. After the reaction was complete, the mixture was cooled to room temperature, and the organic layer was extracted and collected. Compound 6 was then purified. (3) Compound 3, compound 6, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide, and dried toluene were added to a container and heated to 85-95 °C under nitrogen atmosphere with stirring. After the reaction was complete, the mixture was cooled to room temperature, and the organic layer was extracted and collected. The organic layer was then purified to obtain compound 7. The amount of benzylacetone dipalladium used was 3-6% of the molar amount of compound 6. (4) After pre-drying compound 7 under vacuum, dissolve it in o-dichlorobenzene, remove the air, and then add boron tribromide dropwise in a nitrogen atmosphere. Heat the mixture to 170-190 °C and stir under reflux. After the reaction is complete, cool it to -5~5 °C, add N,N-diisopropylethylamine, and then stir the mixture at -5~5 °C. After the reaction is complete, remove o-dichlorobenzene by vacuum distillation, collect the concentrated mother liquor, and purify it to obtain a pale yellow solid powder, which is the compound referred to by general formula B-1.

7. A method for preparing a six-membered and seven-membered boron-nitrogen heterocyclic derivative based on a heavy atom fusion donor as described in claim 1, characterized in that, When the hexa- or hexa-boron-nitrogen heterocyclic derivative satisfies general formula B-2, the following steps are included: The preparation process is as follows: The preparation steps are as follows: (1) Compound 1, Compound 2, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide and dry toluene were added to a container and heated to 110-130 °C under nitrogen atmosphere and stirred under reflux. After the reaction was complete, the mixture was cooled to room temperature, and the organic layer was extracted and collected. Compound 3 was then obtained by purification. (2) Compound 4, compound 5, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide and dry toluene were added to a container and heated to 110-130 °C under nitrogen atmosphere and stirred under reflux. After the reaction was complete, the mixture was cooled to room temperature, and the organic layer was extracted and collected. Compound 6 was then purified. (3) Compound 3, compound 6, benzylacetone dipalladium, tri-tert-butylphosphine tetrafluoroborate, sodium tert-butoxide, and dried toluene were added to a container and heated to 105-115 °C under nitrogen atmosphere with stirring under reflux. After the reaction was complete, the mixture was cooled to room temperature, and the organic layer was extracted and collected. The organic layer was then purified to obtain compound 7. The amount of benzylacetone dipalladium used was 18-22% of the molar amount of compound 6. (4) After drying compound 7 under vacuum, dissolve it in o-dichlorobenzene, remove the air, and then add boron tribromide dropwise in a nitrogen atmosphere. Heat the mixture to 170-190 °C and stir under reflux. After the reaction is complete, cool it to -5~5 °C and add N,N-diisopropylethylamine. Then keep the mixture at -5~5 °C and stir under reflux. After the reaction is complete, remove o-dichlorobenzene by vacuum distillation, collect the concentrated mother liquor, and purify it to obtain a pale yellow solid powder, which is the compound referred to by general formula B-2.

8. The application of the hexa- and hexa-boron-nitrogen heterocyclic derivatives based on heavy atom fusion donors as described in any one of claims 1-3 in organic electroluminescent devices; wherein the hexa- and hexa-boron-nitrogen heterocyclic derivatives based on heavy atom fusion donors are specifically used as guest light-emitting materials and / or sensitizer materials in organic electroluminescent devices.

9. The application as described in claim 8, characterized in that, The electroluminescent device comprises, in sequence: an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode; the light-emitting layer contains the hexa- and hexa-boron-nitrogen heterocyclic derivative.

10. The application as described in claim 9, characterized in that, An exciton blocking layer is also provided between the hole transport layer and the light-emitting layer, and between the light-emitting layer and the electron transport layer.

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