Boron-nitrogen compound with naphtho-carbazole structure and organic electroluminescent device thereof

Abstract

The invention belongs to the technical field of organic electroluminescent materials, and particularly relates to a boron-nitrogen compound with a naphtho-carbazole structure and an organic electroluminescent device.According to the boron-nitrogen compound with the naphtho-carbazole structure, on the basis of multiple resonance nuclei of boron and nitrogen, novel conjugate extension is constructed, and the structure of the boron-nitrogen compound with the naphtho-carbazole structure is improved; the whole conjugation degree of the structure is increased, so that the structure has a relatively strong rigid conjugation skeleton, the non-radiative transition of excited state energy can be reduced, the relaxation of the excited state structure is inhibited, and the fluorescence quantum efficiency is improved; more importantly, due to the introduced naphtho-carbazole unit, the organic electroluminescent material has better electron and hole double injection capability, so that a host material and a sensitizer material can be better matched, and an OLED device prepared from the organic electroluminescent material has lower driving voltage, higher current efficiency and longer service life.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescent materials technology, specifically relating to a boron nitrogen compound with a naphthocarbazole structure and its organic electroluminescent device. Background Technology

[0002] Organic optoelectronic materials are a class of organic materials that possess properties such as the generation, conversion, and transmission of photons and electrons. Currently, the controllable optoelectronic properties of organic optoelectronic materials have been applied to organic light-emitting diodes (OLEDs), organic solar cells (OPVs), organic field-effect transistors (OFETs), and even organic lasers. In recent years, OLEDs have become a very popular new type of flat panel display product both domestically and internationally. OLED displays are characterized by self-emissiveness, wide viewing angle, short response time, high luminous efficiency, wide color gamut, low operating voltage, thin panels, the ability to manufacture large-size flexible panels, and low cost, earning them the reputation as the star flat panel display product of the 21st century.

[0003] In the evolution of organic optoelectronic materials, first-generation fluorescent materials were limited to an exciton utilization rate of 25%. Second-generation phosphorescent materials, while achieving full exciton capture through the spin-orbit coupling effect of heavy metal atoms, suffered from severe efficiency roll-off and strong dependence on precious metals, and the core technology was long monopolized by Japanese and South Korean companies. Third-generation thermally activated delayed fluorescence (TADF) materials reduce the singlet-triplet energy level difference (ΔE) through intramolecular charge transfer state design. ST By utilizing reverse intersystem crossing to achieve exciton upconversion, theoretically, efficiency limitations can be overcome. However, traditional donor-acceptor (DA) type TADF materials suffer from spectral broadening due to molecular relaxation effects, making it difficult to meet the requirements for high color purity.

[0004] The emergence of luminescent materials exhibiting multiple resonance thermally activated delayed fluorescence (MR-TADF) provides a new direction for overcoming the aforementioned bottlenecks. By constructing a rigid conjugated framework using multiple resonance nuclei such as boron / nitrogen, MR-TADF materials achieve high radiative transition rates (>10⁶ s⁻¹). -1 At the same time, the full width at half maximum (FWHM) can be compressed to below 20 nm, significantly improving color purity and device efficiency. Stable and efficient luminescent materials with the MR-TADF effect remain a development goal for the industry. Summary of the Invention

[0005] To address the problems existing in the background art, the present invention provides a boron nitrogen compound having a naphthocarbazole structure, having a structure as shown in any one of general formulas (1), (2), and (3): ; X represents the presence or absence of a bonding relationship; when the bonding relationship is present, X is each independently selected from a single bond, O, S, Se, CR4R4, R4 is methyl or phenyl, when R4 is phenyl, two R4 are not connected or connected by a single bond to form a ring; R1 is each independently selected from hydrogen, deuterium, cyano, C1-C6 alkyl, substituted or unsubstituted C6-C10 aryl, or C3-C10 heteroaryl; 20 20 10 substituted or unsubstituted C3-C6 cycloalkyl, C6-C10 aryl, or C3-C10 heteroaryl; 12 12 ; R2 and R3 are each independently selected from hydrogen, deuterium, cyano, C1-C6 alkyl, substituted or unsubstituted C6-C10 aryl, or C3-C10 heteroaryl; 12 12 ; any two adjacent substituents are not bonded or are bonded to form a saturated or unsaturated C3-C6 cycloalkyl ring; 12 when substitution is present, the substituents are each independently selected from deuterium, cyano, C1-C6 alkyl, C6-C10 aryl, or C3-C10 heteroaryl, n is 1 to the maximum number of substitution sites of the ring, and the heteroatom is N, O, S, or Se. 12

[0006] As a preferred embodiment of the present application, X is selected from a single bond or CR4R4.

[0007] As a preferred embodiment of the present application, R1 is each independently selected from hydrogen, deuterium, cyano, C1-C6 alkyl, substituted or unsubstituted C6-C10 aryl, or C3-C10 heteroaryl. 12 12 As a preferred embodiment of the present application, when substitution is present, the substituents are each independently selected from deuterium, cyano, methyl, t-butyl, phenyl, or pyridyl.

[0008] As a preferred embodiment of the present application, R2 and R3 are each independently selected from hydrogen, deuterium, cyano, methyl, t-butyl, or phenyl.

[0009] As a preferred embodiment of the present application, the specific structure of the boron-nitrogen compound having a naphthocarbazole structure is as follows:

[0010] ; ; ; ; ; ; ; ;​​​​​​​ ; ; ; .

[0011] The application also provides an organic electroluminescent device, comprising an anode, a cathode and an organic thin film layer arranged between the anode and the cathode, wherein the organic thin film layer comprises the boron-nitrogen compound with naphthocarbazole structure.

[0012] As a preferred embodiment of the application, the organic thin film layer comprises a light-emitting layer, and the light-emitting layer comprises the boron-nitrogen compound with naphthocarbazole structure.

[0013] As a preferred embodiment of the application, the organic electroluminescent device is used for manufacturing display devices, lighting sources, signal lights and indicator boards, wherein the display devices include mobile phone display screens, computer display screens, television display screens, smart watch display screens, smart car display panels, VR or AR helmet display screens.

[0014] The application has the following advantages: The boron-nitrogen compound with naphthocarbazole structure provided by the application has a new type of conjugate extension based on the multiple resonance nucleus of boron-nitrogen, increases the overall conjugation degree of the structure, makes the structure have a strong rigid conjugate skeleton, reduces the non-radiative transition of the excited state energy, suppresses the relaxation of the excited state structure, and improves the fluorescence quantum efficiency; more importantly, the introduction of the 4H-naphtho[1,2,3,4-def]carbazole unit makes it have good electron and hole double injection capacity, so as to better match the host material and sensitizer material, and the OLED device prepared therefrom has a lower driving voltage, higher current efficiency and longer service life. DETAILED DESCRIPTION

[0015] The technical solutions of the application will be described clearly and completely below in combination with the preparation examples and device examples. Obviously, the described examples are only some of the examples of the application, rather than all. Based on the examples in the application, all other examples obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0016] Preparation examples

[0017] ; Synthesis of 1-3: 1-1 (5 g, 20.3 mmol), 1-2 (3.2 g, 20.3 mmol), Pd(dppf)Cl2(149 mg, 0.2 mmol), K2CO3(5.6 g, 40.6 mmol) were added into a 250 mL three-neck flask under nitrogen atmosphere, a mixed solution of 102 mL tetrahydrofuran and 34 mL water was added, the reaction was refluxed for 4 hours, after the reaction was completed, it was cooled to room temperature, the organic phase was obtained by filtration, the organic phase was dried over anhydrous magnesium sulfate, then distilled under reduced pressure, the obtained solid was recrystallized with toluene to obtain 1-3 (4.0 g, 71%), the molecular weight determined by mass spectrometry: 277.63 (theoretical value: 277.75); Synthesis of 1-4: 1-3 (4 g, 14.4 mmol), palladium acetate (32 mg, 0.14 mmol), tri-tert-butyl phosphine (58 mg, 0.29 mmol), DBU (4.4 g, 28.8 mmol), 96 mL DMF were added into a 250 mL three-neck flask under nitrogen atmosphere, the reaction was refluxed for 6 hours, after the reaction was completed, water was added to precipitate the product. The crude product was recrystallized with toluene to obtain 1-4 (2.5 g, 70%), the molecular weight determined by mass spectrometry: 241.15 (theoretical value: 241.29); Synthesis of 1-7: 1-5 (9.6 g, 30 mmol), 1-6 (4.0 g, 33 mmol), tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) (0.34 g, 0.3 mmol), potassium carbonate (8.3 g, 60 mmol) were placed into a 250 mL three-neck flask, nitrogen was replaced for three times, under nitrogen atmosphere, toluene / ethanol / water=80 mL / 40 mL / 40 mL was added, the temperature was increased to 60°C, and the reaction was carried out at this temperature for 12 hours, after the reaction system was cooled to room temperature, the organic phase was collected by liquid separation, the organic phase was washed with brine, and the aqueous phase was extracted with ethyl acetate, the organic phases were combined and dried over anhydrous magnesium sulfate, after drying, the solvent was removed by rotary evaporator under reduced pressure to obtain the crude product, the crude product was purified by silica gel column chromatography to obtain 1-7 (7.1 g, 88%), the molecular weight determined by mass spectrometry: 269.21 (theoretical value: 269.09); 1-9: Synthesis: Into a 500 mL three-necked flask, 1-7 (2.7 g, 10 mmol), 1-8 (1.7 g, 10 mmol), cesium carbonate (8.2 g, 25 mmol), N,N-dimethylformamide (100 ml) were added under nitrogen atmosphere. The reaction mixture was heated at 120 °C overnight under nitrogen atmosphere. The heating was stopped and the reaction mixture was allowed to cool to room temperature. 150 ml of water was added and stirred for 10 min. A large amount of white solid was precipitated. The solid was filtered and the cake was washed with ethanol for 2 h. The solid was filtered and dried to give 1-9 (3.0 g, 72%). The molecular weight was determined by mass spectrometry: 418.19 (theoretical value: 418.31). 1-10: Synthesis: Into a 250 mL two-necked flask, 1-9 (4.2 g, 10 mmol), 1-4 (2.4 g, 10 mmol), cesium carbonate (Cs2CO3) (8.2 g, 25 mmol) and N,N-dimethylformamide (DMF) 100 mL were added under nitrogen atmosphere. The reaction mixture was heated at 160 °C for 24 h in an oil bath. The reaction was stopped and the reaction mixture was poured into distilled water. The white solid was filtered and dried. The solid was dissolved in dichloromethane and extracted with dichloromethane / water. The organic layer was dried and concentrated. The residue was purified by column chromatography using dichloromethane and petroleum ether (1:10) as eluent to give 1-10 (4.8 g, 75%). The molecular weight was determined by mass spectrometry: 639.47 (theoretical value: 639.60). Synthesis of compound 1: Into a 250 mL flask, 1-10 (6.4 g, 10 mmol) was dissolved in 250 mL of tert-butyl benzene (TBB). tert-Butyllithium (t-BuLi) (1.6 M) in n-pentane (8 mL) was added slowly at 0 °C under nitrogen atmosphere. The reaction mixture was stirred at 60 °C for 2 h. Boron tribromide (BBr3) (5 g, 20 mmol) was added. The reaction mixture was stirred at room temperature for 1 h. N,N-diisopropylethylamine (DIEA) (2.6 g, 20.2 mmol) was added. The reaction mixture was stirred at 130 °C for 6 h. The reaction mixture was cooled to room temperature. Methanol was added to remove the residual boron tribromide. The mixture was separated and extracted with water and dichloromethane. The combined organic layer was condensed in vacuum and purified by silica gel column chromatography to give compound 1 (1.6 g, 29%). The molecular weight was determined by mass spectrometry: 418.19 (theoretical value: 568.49).

[0018] Example 2: Synthesis of compound 12 ; Synthesis of 12-2 was the same as 1-7 except that 12-1 was used instead of 1-6. The molecular weight was determined by mass spectrometry: 421.12 (theoretical value: 421.28). 12-4 was synthesized in the same manner as 1-9, except that 12-2 was used to replace 1-7 and 12-3 was used to replace 1-8. The molecular weight determined by mass spectrometry: 680.59 (theoretical value: 680.71); 12-5 was synthesized in the same manner as 1-10, except that 12-4 was used to replace 1-9. The molecular weight determined by mass spectrometry: 901.83 (theoretical value: 901.99); Compound 12 was synthesized in the same manner as Compound 1, except that 12-5 was used to replace 1-10. The molecular weight determined by mass spectrometry: 830.75 (theoretical value: 830.88).

[0019] Example 3: Synthesis of Compound 25 ; Synthesis of 25-1: Compound 1-4 (2.5 g, 10.4 mmol) was dissolved in 50 ml of DMF under a nitrogen atmosphere, and then 4.0 g of NBS (22.8 mmol, dissolved in 19 ml of DMF) was added dropwise to the reaction solution at 0°C over 30 minutes. After the reaction was completed, water was added to re-precipitate the product. The crude product was recrystallized from toluene to obtain 25-1 (3.5 g, 85%), and the molecular weight determined by mass spectrometry: 399.17 (theoretical value: 399.09); Synthesis of 25-2: 25-1 (4.0 g, 10 mmol), 1-6 (4.6 g, 24 mmol), Pd(PPh3)4 (0.24 g, 0.2 mmol), and potassium carbonate (8.2 g, 60 mmol) were added to a 250 ml three-necked flask under a nitrogen atmosphere, and 120 ml of a mixed solvent of dioxane and water (60 ml each) was added. The reaction solution was stirred at 100°C for 10 hours under a nitrogen atmosphere. After the reaction was completed, the reaction solution was cooled to room temperature, and then extracted with dichloromethane and water three times. After the liquid was separated, the organic phase was concentrated using a rotary evaporator to obtain a crude product. The crude product was purified using column chromatography to obtain 25-2 (3.4 g, 87%), and the molecular weight determined by mass spectrometry: 393.37 (theoretical value: 393.49); 25-3 was synthesized in the same manner as 1-9, except that 12-3 was used to replace 1-8. The molecular weight determined by mass spectrometry: 528.36 (theoretical value: 528.51); 25-4 was synthesized in the same manner as 1-10, except that 25-3 was used to replace 1-9 and 25-2 was used to replace 1-4. The molecular weight determined by mass spectrometry: 901.84 (theoretical value: 901.99); The synthesis of compound 25 is the same as that of compound 1, except that 25-4 is used to replace 1-10. The molecular weight determined by mass spectrometry is 830.73 (theoretical value: 830.88).

[0020] Example 4: Synthesis of compound 48 ; Synthesis of 48-1: 1-4 (2.4 g, 10 mmol), 50 ml heavy water, 20 ml toluene were added into a 250 ml three-necked flask under nitrogen atmosphere, and stirred at 120°C for 24 h. After the reaction system was cooled to room temperature, it was extracted with dichloromethane and water for 3 times. After separation, the organic phase was concentrated by rotary evaporator to obtain the crude product. After the crude product was purified by column chromatography, 48-1 (2.3 g, 90%) was obtained, and the molecular weight determined by mass spectrometry was 251.47 (theoretical value: 251.35); The synthesis of 48-3 is the same as that of 1-9, except that 48-2 is used to replace 1-8. The molecular weight determined by mass spectrometry is 432.11 (theoretical value: 432.29); The synthesis of 48-4 is the same as that of 1-10, except that 48-3 is used to replace 1-9, and 48-1 is used to replace 1-4. The molecular weight determined by mass spectrometry is 663.52 (theoretical value: 663.64); The synthesis of compound 48 is the same as that of compound 1, except that 48-4 is used to replace 1-10. The molecular weight determined by mass spectrometry is 591.38 (theoretical value: 591.52).

[0021] Example 5: Synthesis of compound 81 ; Synthesis of 81-1: 1-5 (2.6 g, 8.0 mmol), 12-3 (2.5 g, 8.8 mmol) and potassium carbonate (1.82 g, 13.2 mmol), 100 mL DMF were added into a 250 ml three-necked flask under nitrogen atmosphere, 115 mg Cu2O was added, and the temperature was raised to 150°C and stirred for 8 hours. After the reaction was completed, the reaction solution was extracted with dichloromethane and water, and the organic phase was concentrated. After purification by column chromatography, 81-1 (3.2 g, 85%) was obtained, and the molecular weight determined by mass spectrometry was 470.29 (theoretical value: 470.40); The synthesis of 81-3 is the same as that of 1-9, except that 81-1 is used to replace 1-7, and 81-2 is used to replace 1-8. The molecular weight determined by mass spectrometry is 658.55 (theoretical value: 658.70); The synthesis methods of 81-4 and 1-10 are the same, except that 1-9 is replaced by 81-3. The molecular mass determined by mass spectrometry is 880.81 (theoretical value: 880.97). Compound 81 was synthesized using the same method as compound 1, except that 1-10 was replaced with 81-4. The molecular mass determined by mass spectrometry was 809.72 (theoretical value: 809.86).

[0022] Example 6: Synthesis of Compound 128 ; The synthesis methods of 128-2 and 25-2 are the same, the difference being that 128-1 is used instead of 25-1. The molecular mass determined by mass spectrometry is 485.77 (theoretical value: 485.63). The synthesis methods of 128-4 and 1-7 are the same, except that 1-6 is replaced by 128-3. The molecular mass determined by mass spectrometry is 270.19 (theoretical value: 270.08). The synthesis methods of 128-5 and 1-10 are the same, the difference being that 1-9 is replaced by 128-4. The molecular mass determined by mass spectrometry is 491.22 (theoretical value: 491.36). The synthesis methods of 128-6 and 1-9 are the same, the difference being that 1-7 is replaced by 128-5 and 1-8 is replaced by 128-2. The molecular mass determined by mass spectrometry analysis is 954.83 (theoretical value: 954.97). Compound 128 was synthesized using the same method as compound 1, except that 1-10 was replaced with 128-6. The molecular mass determined by mass spectrometry was 883.71 (theoretical value: 883.86).

[0023] Example 7: Synthesis of Compound 148 ; Synthesis of 148-1: Under a nitrogen atmosphere, 12-2 (4.7 g, 10 mmol), 1-4 (5.3 g, 22 mmol), cesium carbonate (16.4 g, 5 mmol), and N,N-dimethylformamide (100 ml) were added to a 500 mL three-necked flask. The reaction was carried out at 160 °C for 48 hours under nitrogen protection. Heating was stopped, and after cooling to room temperature, 150 ml of water was added and stirred for 10 min. A large amount of white solid precipitated. The solid was filtered, and the filter cake was washed with ethanol for 2 h. After cooling, the solid was filtered again to obtain 148-1 (7.3 g, 80%). The molecular weight determined by mass spectrometry was 418.19 (theoretical value: 912.98). The synthesis of compound 148 was the same as that of compound 1 except that 148-1 replaced 1-10. The molecular weight was determined by mass spectrometry: 841.69 (theoretical value: 841.87).

[0024] Example 8: Synthesis of compound 171 ; The synthesis of 171-2 was the same as that of 1-7 except that 171-1 replaced 1-6. The molecular weight was determined by mass spectrometry: 345.07 (theoretical value: 345.19); The synthesis of 171-4 was the same as that of 25-2 except that 171-3 replaced 1-6. The molecular weight was determined by mass spectrometry: 353.63 (theoretical value: 353.51); The synthesis of 171-6 was the same as that of 1-7 except that 171-5 replaced 1-5. The molecular weight was determined by mass spectrometry: 345.07 (theoretical value: 343.65); Synthesis of 171-7: 171-6 (3.4 mg, 10 mmol), bis(pinacolato)diboron (5.6 g, 22 mmol), Pd(dppf)Cl2(146 mg, 0.2 mmol) and potassium acetate (5.9 g, 60 mmol) were dissolved in 100 ml of 1,4-dioxane in a 250 ml three-necked flask under nitrogen atmosphere. The reaction system was stirred at 100°C for 6 h under nitrogen protection. After the reaction system was cooled to room temperature, it was extracted with dichloromethane and water for 3 times. After the organic phase was concentrated, column chromatography was used for purification and recrystallization to obtain 171-7 (3.3 g, 85%), and the molecular weight was determined by mass spectrometry: 390.58 (theoretical value: 390.71); The synthesis of 171-8 was the same as that of 1-3 except that 171-7 replaced 1-2. The molecular weight was determined by mass spectrometry: 429.81 (theoretical value: 429.95); The synthesis of 171-9 was the same as that of 1-4 except that 171-8 replaced 1-3. The molecular weight was determined by mass spectrometry: 393.37 (theoretical value: 393.49); The synthesis of 171-10 was the same as that of 1-9 except that 171-2 replaced 1-7 and 171-9 replaced 1-8. The molecular weight was determined by mass spectrometry: 718.55 (theoretical value: 718.67); The synthesis of 171-11 was the same as that of 1-10 except that 171-10 replaced 1-9 and 171-4 replaced 1-4. The molecular weight was determined by mass spectrometry: 1052.03 (theoretical value: 1052.17); The synthetic method of compound 171 is the same as that of compound 1, except that 171-11 replaces 1-10. The molecular weight determined by mass spectrometry: 981.17 (theoretical value: 981.06).

[0025] Example 9: Synthesis of compound 197 ; The synthetic method of 197-2 is the same as that of 1-3, except that 197-1 replaces 1-1. The molecular weight determined by mass spectrometry: 374.52 (theoretical value: 374.64); The synthetic method of 197-3 is the same as that of 1-4, except that 197-2 replaces 1-3. The molecular weight determined by mass spectrometry: 338.06 (theoretical value: 338.18); Synthesis of 197-5: 197-3 (3.4 g, 10 mmol), 197-4 (2.9 g, 11 mmol), tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) (175 mg, 0.2 mmol), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (X-phos) (90 mg, 0.2 mmol), sodium tert-butoxide (1.5 g, 15 mmol) and 100 mL of toluene were added to a 250 mL three-necked flask under a nitrogen atmosphere. The reaction system was warmed to 110°C and stirred for 8 hours. After the reaction was completed, the reaction mixture was cooled to room temperature. 100 mL of deionized water was added to the reaction system, and the organic phase was collected by liquid separation, dried with anhydrous sodium sulfate, and then the organic reagent was removed by rotary evaporation under reduced pressure. The obtained crude product was purified by silica gel column chromatography to obtain 197-5 (15.8 g, 83%). The molecular weight determined by mass spectrometry: 470.22 (theoretical value: 470.39); The synthetic method of 197-7 is the same as that of 1-10, except that 197-5 replaces 1-9 and 197-6 replaces 1-4. The molecular weight determined by mass spectrometry: 731.70 (theoretical value: 731.82); The synthetic method of compound 197 is the same as that of compound 1, except that 197-7 replaces 1-10. The molecular weight determined by mass spectrometry: 660.58 (theoretical value: 660.71).

[0026] Example 10: Synthesis of compound 217 ; The synthesis method of 217-1 is the same as that of 1-3, except that 197-1 is used to replace 1-1, and 171-7 is used to replace 1-2. The molecular weight determined by mass spectrometric analysis is 526.69 (theoretical value: 526.83); The synthesis method of 217-2 is the same as that of 1-4, except that 217-1 is used to replace 1-3. The molecular weight determined by mass spectrometric analysis is 490.51 (theoretical value: 490.38); The synthesis method of 217-3 is the same as that of 197-5, except that 217-2 is used to replace 197-3. The molecular weight determined by mass spectrometric analysis is 622.45 (theoretical value: 622.58); The synthesis method of 217-4 is the same as that of 1-10, except that 217-3 is used to replace 1-9, and 12-3 is used to replace 1-4. The molecular weight determined by mass spectrometric analysis is 882.12 (theoretical value: 882.00); The synthesis method of compound 217 is the same as that of compound 1, except that 217-4 is used to replace 1-10. The molecular weight determined by mass spectrometric analysis is 810.73 (theoretical value: 810.89).

[0027] Device Embodiment In order to evaluate the light-emitting performance of the compounds described in the present application in organic electroluminescent devices, some representative electroluminescent device embodiments are also provided. The structure of the device can be described from bottom to top as [ITO / HI (5 nm) / HT-1 (40 nm) / HT-2 (20 nm) / Host:S-17 (25wt%):Dopant (2wt%) (25 nm) / HB (10 nm) / ET (30 nm) / LiF (1 nm) / Al (100 nm)], wherein the symbol " / " represents layering, and the size in the parentheses represents the thickness of the layer.

[0028] Preparation of Example 1: Transparent ITO glass was used as the substrate material for device preparation. First, the ITO glass was ultrasonically treated with 5% ITO solution for 30 min, then ultrasonically washed with distilled water (2 times), acetone (2 times), and isopropanol (2 times), and finally stored in isopropanol. Before use, the surface of the ITO glass was carefully wiped with acetone and isopropanol cotton balls, and then dried after isopropanol rinsing, followed by plasma treatment for 5 min for standby; The hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, electron injection layer, and metal electrode were prepared by evaporation process. When the vacuum degree of the vacuum evaporation system reached 5~10 -4The deposition starts when the pressure is below 10-6 Pa, and the deposition rate is determined by a Sycon film thickness meter. The deposition rate of the organic material is 0.5 Å / s; the deposition rate of the electron injection layer LiF is 0.1 Å / s; the metal electrode is Al; the deposition rate is 5 Å / s; HI is used as a hole injection layer; HT-1 is used as a hole transport layer; HT-2 is used as an electron blocking layer material; in the light-emitting layer, Host is used as a host material, S-17 is used as a sensitizer material, compound 1 is used as a dopant material; HB is used as a hole blocking layer material; and ET is used as an electron transport layer material. The device is packaged with UV-cured resin in a nitrogen glove box.

[0029] Preparation of Examples 2-10: In the formation of the light-emitting layer, the compound 1 in Example 1 is replaced by the corresponding compound in Table 1, and the organic electroluminescent device is prepared by the same method as Example 1.

[0030] Preparation of Comparative Examples 1-2: In the formation of the light-emitting layer, the compound 1 in Example 1 is replaced by the corresponding compound in Table 1, and the organic electroluminescent device is prepared by the same method as Example 1.

[0031] The structures of the compounds used in the device are as follows: .

[0032] The driving voltage, current efficiency and lifetime LT90 of the OLED device provided above are tested; the driving voltage and current efficiency are both tested by a Fosil IVL test system; LT90 refers to the time required for the luminance to drop to 90% of the original luminance while keeping the current density unchanged at the initial luminance of 1000 nit; the driving voltage, current efficiency and LT90 data are all relative values (based on Comparative Example 1) when the luminance is 1000 cd / m 2 The performance test results of the organic electroluminescent device are shown in Table 1: ; As can be seen from the above table, by structural design, the introduction of a naphthocarbazole structural unit into the boron-nitrogen compound makes the overall conjugated group of the compound larger, which improves the material performance, and a compound suitable for use as a light-emitting layer dopant material is obtained, and thus the organic electroluminescent device prepared therefrom has a lower driving voltage, higher current efficiency and longer service life.

[0033] The above examples only list the effect data of devices made from a part of the structural formula, which is a representative sample test. In terms of experimental data, the overall data is not much different, and can represent the effects of other unlisted structures.

[0034] Many modifications and variations of this application can be apparent to those skilled in the art without departing from the spirit and scope of the application. Accordingly, it is intended that all

[0035] The applicant declares that the organic electroluminescent material and the organic electroluminescent device of the present application are illustrated by the above examples, but the present application is not limited to the above examples, i.e. it does not mean that the present application must be implemented depending on the above examples. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of each raw material of the product of the present application, addition of auxiliary ingredients, selection of specific modes, etc. fall within the scope of protection and disclosure of the present application.

Claims

1. A boron-nitrogen compound having a naphthocarbazole structure, characterized by, The compound has a structure as shown in any one of general formula (1), general formula (2), general formula (3): ； X represents the presence or absence of a bond; when the bond is present, X is independently selected from a single bond, O, S, Se, CR4R4, R4 is methyl or phenyl, when R4 is phenyl, two R4 are not connected or connected by a single bond to form a ring; R1 is independently selected from hydrogen, deuterium, cyano, C1-C 20 Alkyl, C1-C 20 Alkoxy, substituted or unsubstituted C3-C 10 cycloalkyl, substituted or unsubstituted C6-C 12 Aryl or C3-C 12 The heteroaryl group; R2 and R3 are each independently selected from hydrogen, deuterium, cyano, C1-C6 alkyl, substituted or unsubstituted C6-C 12 Aryl or C3-C 12 The heteroaryl group; any two adjacent substituents are not bonded together or are bonded together to form a saturated or unsaturated C3-C group. 12 ring; When substitution is present, the substituents are each independently selected from deuterium, cyano, C1-C6 alkyl, C6 ... 12 The aryl group, C3-C6 heteroaryl group, n is from 1 to the largest substitution site number of the ring, and the heteroatoms are N, O, S, and Se.

2. The boron-nitrogen compound having a naphthocarbazole structure according to claim 1, wherein X is selected from a single bond or CR4R 4。 3. The boron-nitrogen compound having a naphthocarbazole structure according to claim 1, wherein R1 is independently selected from hydrogen, deuterium, cyano, C1-C6 alkyl, substituted or unsubstituted C6-C6. 12 Aryl or C3-C 12 Mixed aromatic compounds.

4. The boron-nitrogen compound having a naphthocarbazole structure according to claim 1, wherein When substituted, the substituent is independently selected from deuterium, cyano, methyl, tert-butyl, phenyl, pyridyl.

5. The boron-nitrogen compound having a naphthocarbazole structure according to claim 1, wherein R2 and R3 are independently selected from hydrogen, deuterium, cyano, methyl, tert-butyl, phenyl.

6. The boron-nitrogen compound having a naphthocarbazole structure according to any one of claims 1 to 5, wherein The specific structure of the compound is as follows: ； ； ； ； ； ； ； ； ； ； 。 7. An organic electroluminescent device comprising an anode, a cathode, and an organic thin film layer disposed between the anode and the cathode, characterized in that, The organic thin film layer contains the boron-nitrogen compound with a naphthocarbazole structure according to any one of claims 1 to 6.

8. The organic electroluminescent device according to claim 7, characterized in that The organic thin film layer contains the boron-nitrogen compound with a naphthocarbazole structure according to any one of claims 1 to 6.

9. The organic electroluminescent device according to claim 7, characterized in that, The organic electroluminescent device is used for manufacturing display devices, lighting sources, signal lights, and signs, and the display devices include mobile phone display screens, computer display screens, television display screens, smart watch display screens, smart car display panels, VR or AR helmet display screens.

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