Multiple resonance heat-activated delayed fluorescence compound and organic electroluminescent device thereof

Abstract

The application belongs to the technical field of organic electroluminescent materials, and particularly relates to a multiple resonance thermally activated delayed fluorescence compound, and simultaneously relates to a thermally activated delayed fluorescence material containing the compound, an organic electroluminescent device, and application of the compound, the material and the device in the field of display and illumination. The multiple resonance thermally activated delayed fluorescence compound provided by the application takes a naphthoindolocarbazole fused ring unit as a strong donor, takes a B atom as a core electron-withdrawing unit, constructs a rigid MR conjugated skeleton with N-B alternately arranged, effectively reduces the optical band gap of the material through the strong electron-donating ability of the fused ring donor, and realizes red light band emission. Meanwhile, based on the multiple resonance effect, narrow-band red light emission is realized, and the color purity is excellent, which can fully meet the stringent requirements of the red light color gamut of the ultra-high-definition display BT.2020 standard.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescent materials technology, specifically relating to a multi-resonance thermally activated delayed fluorescence compound, as well as thermally activated delayed fluorescence materials containing the compound, organic electroluminescent devices, and the application of the compound, materials, and devices in the fields of display and lighting. Background Technology

[0002] Organic light-emitting diodes (OLEDs) have excellent characteristics such as self-illumination, wide viewing angle, fast response speed, thinness and flexibility, low driving voltage and high luminous efficiency. They are considered to be the most promising core technology in the next generation of flat panel displays and solid-state lighting. They are currently widely used in commercial products such as smartphones, tablets, TVs and automotive displays.

[0003] According to the principle of electron spin statistics, organic light-emitting materials generate 25% singlet excitons and 75% triplet excitons under electro-excitation. Traditional fluorescent materials can only emit light using singlet excitons, with a theoretical upper limit of only 25% for internal quantum efficiency, making it difficult to break through the efficiency barrier. While phosphorescent materials can utilize both singlet and triplet excitons simultaneously through spin-orbit coupling of heavy metal atoms, achieving 100% internal quantum efficiency, they suffer from problems such as high cost of precious metals, poor stability of blue light materials, and short device lifetime, limiting their large-scale application.

[0004] Thermally activated delayed fluorescence (TADF) materials can pass through an extremely small singlet-triplet bandgap (ΔE). ST This technology allows triplet excitons to be converted into singlet excitons for luminescence via a reverse system-relation crossover (RISC) process. Theoretically, this can achieve 100% internal quantum efficiency, and it is free of precious metals and inexpensive, making it a research hotspot in the OLED field in recent years. Among them, MR-TADF materials based on the multiple resonance (MR) effect are based on the core of alternating the introduction of electron-donating nitrogen (N) atoms and electron-withdrawing boron (B) atoms into a rigid conjugated framework. The alternating arrangement of N and B atomic orbitals achieves local separation of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), resulting in narrow-band emission, high color purity, high fluorescence quantum efficiency (PLQY), and an extremely small singlet-triplet bandgap (ΔE). ST Its core advantage lies in its core luminescent material, which meets the color gamut standards for ultra-high-definition displays.

[0005] Currently, research on MR-TADF materials mainly focuses on the blue and green light bands, while the development of high-performance narrowband red MR-TADF materials still faces significant technical bottlenecks. Red light emission requires materials with narrower optical band gaps, but existing red MR-TADF materials mostly achieve redshift by extending the conjugation length. This easily leads to excessively large conjugation planes and severe intermolecular π-π stacking, causing problems such as broadening of the emission spectrum, decreased color purity, intensified nonradiative transitions, severe roll-off in device efficiency, and short lifespan. These issues make it difficult to meet the stringent application requirements of the BT.2020 standard for ultra-high-definition displays, which demands high color purity, high efficiency, and long lifespan for red light materials.

[0006] Based on this, developing a new type of red MR-TADF material with a simple synthesis route and the characteristics of narrowband red light emission, high luminous efficiency, low efficiency roll-off, high thermal stability and chemical stability is of great practical significance for promoting the industrial application of OLED red light materials in the field of ultra-high-definition display. Summary of the Invention

[0007] In view of this, the main objective of this invention is to provide a multiple resonant thermally activated delayed fluorescence material, an organic light-emitting device containing the same, and its applications, in order to solve the aforementioned technical problems. The technical solution of this invention is as follows: A multi-resonance thermally activated delayed fluorescence compound, the structure of which is represented by general formula (I) or general formula (II): ; Rings A through H are each independently selected from one or more R-substituted or unsubstituted C6 through C6. 30 aryl, one or more R-substituted or unsubstituted C3-C 30 Mixed aromatics; X is selected from O, S, Se, NR1 or CR2R3; R, R1, R2, and R3 are each independently selected from hydrogen, deuterium, halogen, cyano, nitro, or one or more R4-substituted or unsubstituted C1-C groups. 30 Chain alkyl groups, one or more R4-substituted or unsubstituted C3~C 20 Cycloalkyl, one or more R4-substituted or unsubstituted C1~C 30 Alkoxy, one or more R4-substituted or unsubstituted C6~C 30 aryl, one or more R4-substituted or unsubstituted C3~C 30 Heteroaryl, one or more R4-substituted or unsubstituted diarylamines, one or more R4-substituted or unsubstituted C6-C 18 Arylsilyl groups are either cyclic or non-cyclic, with n being 1 to the largest substitution site on the ring. R4 groups are independently selected from hydrogen, deuterium, halogen, cyano, nitro, C1~C4.20 Chain alkyl, C3~C 20 cycloalkyl, C1~C 20 Alkoxy, C6~C 20 Aryl, C3~C 20 Mixed aromatics; The heteroatoms in the heteroaryl group are selected from N, O, S, Se, Si, and P.

[0008] As a preferred embodiment of the present invention, each of rings A to H is independently selected from one or more R-substituted or unsubstituted C6 to C6 rings. 18 Aryl or one or more R-substituted or unsubstituted C6-C 18 Mixed aromatic compounds.

[0009] As a preferred embodiment of the present invention, R, R1, R2, and R3 are each independently selected from hydrogen, deuterium, halogen, cyano, nitro, and one or more R4-substituted or unsubstituted C1-C groups. 12 Chain alkyl groups, one or more R4-substituted or unsubstituted C3~C 12 Cycloalkyl, one or more R4-substituted or unsubstituted C1~C 12 Alkoxy, one or more R4-substituted or unsubstituted C6~C 12 aryl, one or more R4-substituted or unsubstituted C3~C 12 Heteroaryl, one or more R4-substituted or unsubstituted diarylamines, one or more R4-substituted or unsubstituted C6-C 12 Arylsilyl groups are either cyclic or non-cyclic, with two adjacent substituents linked together.

[0010] As a preferred embodiment of the present invention, each of the R4 elements is independently selected from hydrogen, deuterium, and C1~C2. 12 Chain alkyl, C3~C 12 cycloalkyl, C1~C 12 Alkoxy, C6~C 12 Aryl, C3~C 12 Mixed aromatic compounds.

[0011] As a preferred embodiment of the present invention, the specific structure of the multiple resonance thermally activated delayed fluorescence compound is shown below: ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; .

[0012] Another object of the present invention is to provide an organic electroluminescent device comprising an anode, a cathode, and an organic functional layer disposed between the anode and the cathode, the organic functional layer comprising a light-emitting layer comprising the aforementioned resonant thermally activated delayed fluorescence compound.

[0013] As a preferred embodiment of the present invention, the re-resonance thermally activated delayed fluorescence compound is used as a luminescent dye and / or sensitizer in the luminescent layer.

[0014] The present invention also provides a display screen or display panel, wherein the display screen or display panel employs the above-mentioned organic electroluminescent device.

[0015] As a preferred embodiment of the present invention, the display screen or display panel is an OLED display.

[0016] A final objective of the present invention is to provide an electronic device having the aforementioned electronic device having a display screen or display panel.

[0017] The beneficial effects of this invention are as follows: 1. The multi-resonance thermally activated delayed fluorescence compound provided by this invention uses naphthoindolocarbazole fused ring units as strong donors and boron atoms as core electron-withdrawing units to construct a rigid MR conjugated framework with alternating boron and nitrile atoms. The strong electron-donating ability of the fused ring donors effectively reduces the optical band gap of the material, achieving red light emission. At the same time, based on the multi-resonance effect, it achieves narrow-band red light emission with a half-width at half-maximum of ≤40 nm and excellent color purity, which can fully meet the stringent requirements of the BT.2020 standard for ultra-high-definition display for red light color gamut. 2. The compounds of this invention, through the rigid structure of a naphthoindolocarbazole fused ring, effectively suppress molecular vibration and rotation, reduce nonradiative transition losses, and significantly improve the fluorescence quantum efficiency of the material. Simultaneously, the sterically hindered fused ring structure effectively suppresses intermolecular π-π stacking, reduces concentration quenching and efficiency roll-off, and improves the operational stability of the device. 3. The compounds of the present invention have excellent chemical and thermal stability, high thermal decomposition temperature, are suitable for vacuum evaporation to prepare OLED devices, and have strong compatibility with existing OLED industrial production lines. 4. The compound of the present invention is used as a luminescent dye in the luminescent layer of OLED devices. The prepared red OLED devices achieve low driving voltage, low efficiency roll-off, high external quantum efficiency, narrow half-width, and long lifespan. Compared with existing commercial red light materials, the device efficiency and stability are significantly improved, and it has broad industrial application prospects in the fields of high-definition display and solid-state lighting. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a structural diagram of an example device in this invention.

[0019] The attached diagrams are labeled as follows: Anode layer 1, Hole injection layer 2, Hole transport layer 3, Electron blocking layer 4, Light emitting layer 5, Electron transport layer 6, Electron injection layer 7, and Cathode layer 8. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the embodiments described herein are only for explaining and illustrating the present invention and are not intended to limit the scope of protection of the present invention. Experimental methods in the embodiments of the present invention that do not specify specific conditions are all carried out according to conventional experimental conditions in the art or according to the conditions recommended by reagent / instrument manufacturers; solvents, reagents, and intermediate raw materials used in the embodiments of the present invention, unless otherwise specified, are all obtained through commercial purchase or prepared by synthesis methods known in the art.

[0021] The present invention will be described in detail below with several specific embodiments. The compounds of the present invention can be synthesized with reference to the specific synthesis examples shown below. However, it should be noted that obtaining the compounds is not limited to the synthesis methods and raw materials used in the present invention. Those skilled in the art can also select other methods or routes to obtain the novel compounds proposed in the present invention. The compounds for which synthesis methods are not mentioned in the present invention are all raw material products obtained through commercial means, or self-made using these raw material products according to known methods.

[0022] The solvents and reagents used in the synthesis examples of this invention, such as petroleum ether, ethyl acetate, dichloromethane, tetrahydrofuran, potassium carbonate, cesium carbonate, tetra(triphenylphosphine)palladium, and carbazole, were all purchased from domestic commercial channels such as Shanghai Titan Technology Co., Ltd., Xilong Chemical Co., Ltd., and Shanghai Bide Pharmaceutical Technology Co., Ltd.; naphthoindolocarbazole raw materials can be purchased through commercial channels or synthesized by methods known in the art.

[0023] The mass spectrometry analysis of the compounds in this invention was performed using an ABSCIEX 4000QTRAP mass spectrometer.

[0024] The present invention will be further described in detail below with reference to specific embodiments. The present invention is not limited to these embodiments in any way.

[0025] Synthesis Example 1: Synthesis of Compound 1 and Compound 5 ; Synthesis of 1-3: In a double-necked flask under a nitrogen atmosphere, 1-1 (10 mmol), 1-2 (10 mmol), and cesium carbonate (40 mmol) were dissolved in 150 mL of N,N-dimethylformamide (DMF), and the mixture was heated to 150 °C and reacted for 12 hours. After the reaction was completed and cooled, the solution was poured into methanol, a suitable amount of water was added, the mixture was filtered, washed twice with 100 mL of methanol, and dried to obtain 1-3. MS: 358.72 (theoretical value: 358.66). Synthesis of 1-5: In a double-necked flask under nitrogen atmosphere, 1-3 (10 mmol), 1-4 (10 mmol), tris(dibenzylacetone) dipalladium (1 mmol), tri-tert-butylphosphine tetrafluoroborate (2 mmol), and sodium tert-butoxide (12 mmol) were added sequentially. 100 mL of dry toluene was added, and the mixture was heated to 110 °C and reacted for 12 hours. After cooling, the organic phase was separated and collected. The organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated. The compounds were separated by silica gel column chromatography using petroleum ether:dichloromethane = 10:1 as the developing solvent to obtain 1-5. MS: 371.01 (theoretical value: 370.88). Synthesis of 1-6: In a double-necked flask under a nitrogen atmosphere, 1-5 (10 mmol), 1-1 (10 mmol), and cesium carbonate (40 mmol) were dissolved in 150 mL of N,N-dimethylformamide (DMF), and the mixture was heated to 150 °C and reacted for 12 hours. After the reaction was completed and cooled, the solution was poured into methanol, a suitable amount of water was added, the mixture was filtered, washed twice with 100 mL of methanol, and dried to obtain 1-6. MS: 560.46 (theoretical value: 560.32). Synthesis of 1-8: In a double-necked flask under nitrogen atmosphere, 1-6 (10 mmol), 1-7 (10 mmol), tris(dibenzylacetone)palladium (1 mmol), tri-tert-butylphosphine tetrafluoroborate (2 mmol), and sodium tert-butoxide (12 mmol) were added sequentially. 100 mL of dry toluene was added, and the mixture was heated to 110 °C and reacted for 12 hours. After cooling, the organic phase was separated and collected. The organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated. The compounds were separated by silica gel column chromatography using petroleum ether:dichloromethane = 10:1 as the developing solvent to give 1-8. MS: 859.98 (theoretical value: 859.85). Synthesis of Compounds 1 and 5: 1-8 (1 mmol) was dissolved in 20 mL of tert-butylbenzene in a sealed tube. After cooling to -78 °C, a pentane solution of tert-butyllithium (1 M, 2.5 mL) was added, followed by heating to 40 °C and reacting for 6 hours. The mixture was then cooled again to -78 °C, and boron tribromide (3 mmol) was slowly added. The mixture was then heated to 30 °C and stirred for 1 hour. After cooling to 0 °C, diisopropylethylamine (5 mmol) was added, followed by heating to 160 °C and reacting for 12 hours. The solvent was removed under vacuum, and the mixture was column-securities using a silica gel column with petroleum ether:dichloromethane = 10:1 as the developing solvent to give Compound 1 (yield 12%, MS: 806.67) and Compound 5 (yield 13%, MS: 806.70) with a theoretical value of 806.54.

[0026] Synthesis Example 2: Synthesis of Compounds 91 and 95 ; The synthesis method of 91-3 is the same as that of 1-3, except that 91-1 is used to replace 1-1 and 91-2 is used to replace 1-2. MS: 485.05 (theoretical value: 484.91); The synthesis method of 91-5 is the same as that of 1-5, the difference is that 1-3 is replaced by 91-3 and 1-4 is replaced by 91-4, MS: 511.02 (theoretical value: 511.15); The synthesis methods for 91-7 and 1-6 are the same, except that 91-5 is used to replace 1-5 and 91-6 is used to replace 1-1. MS: 776.81 (theoretical value: 776.68). The synthesis methods for 91-9 and 1-8 are the same, except that 1-6 is replaced by 91-7 and 1-7 is replaced by 91-8. MS: 1188.32 (theoretical value: 1188.44). Compounds 91 and 95 were synthesized using the same method as compounds 1 and 5, except that 1-8 were replaced with 91-9, resulting in compounds 91 (yield 13%, MS: 1135.27) and 95 (yield 10%, MS: 1135.25) with a theoretical value of 1135.13.

[0027] Synthesis Example 3: Synthesis of Compound 96 and Compound 100 ; The synthesis methods for 96-2 and 1-3 are the same, except that 1-2 is replaced with 96-1. MS: 460.82 (theoretical value: 460.76). The synthesis methods for 96-3 and 1-5 are the same, except that 96-2 is used to replace 1-3 and 91-4 is used to replace 1-4. MS: 487.13 (theoretical value: 487.00). The synthesis methods for 96-4 and 1-6 are the same, except that 96-3 is used to replace 1-5 and 91-6 is used to replace 1-1. MS: 752.46 (theoretical value: 752.53). The synthesis methods for 96-5 and 1-8 are the same, except that 96-4 is used to replace 1-6 and 91-8 is used to replace 1-7. MS: 1164.32 (theoretical value: 1164.29). Compounds 96 and 100 were synthesized using the same method as compounds 1 and 5, except that 1-8 were replaced with 96-5, resulting in compounds 96 (yield 17%, MS: 1111.03) and 100 (yield 20%, MS: 1110.87) with a theoretical value of 1110.98.

[0028] Synthetic Example 4: Synthesis of Compounds 121 and 123 ; The synthesis method of 121-1 is the same as that of 1-3, except that 1-2 is replaced by 91-2. MS: 470.69 (theoretical value: 470.88); The synthesis methods for 121-2 and 1-5 are the same, except that 1-3 is replaced with 121-1. MS: 482.96 (theoretical value: 483.10). The synthesis method of 121-3 is the same as that of 1-6, except that 1-5 is replaced by 121-2. MS: 672.66 (theoretical value: 672.53); The synthesis methods for 121-4 and 1-8 are the same, except that 1-6 is replaced with 121-3 and 1-7 is replaced with 91-8. MS: 1084.17 (theoretical value: 1084.29). The synthesis methods of compounds 121-5 and 123-5 are the same as those of compounds 1 and 5, except that 1-8 is replaced by 121-4 to obtain 121-5 (MS: 1030.82) and 123-5 (MS: 1030.99) with theoretical values ​​of 1030.97. Synthesis of compound 121: 121-5 (5 mmol) and dichloromethyl ether (6.0 mmol) were dissolved in 20 mL of 1,2-dichlorobenzene (o-DCB). The solution was cooled to 0°C, and TiCl4 (1.33 g, 7.0 mmol) was added under a nitrogen atmosphere. The mixture was stirred at 50°C for 4 hours. The reaction mixture was quenched with sodium carbonate, extracted three times with dichloromethane / water, and then dried over anhydrous MgSO4. The crude product was purified by chromatography on silica gel (PE / EA = 8:1) to give compound 121, yield: 42%, MS: 1056.85 (theoretical value: 1056.97). Compound 123 was synthesized in the same way as compound 121, except that 121-5 was replaced with 123-5. MS: 1056.89 (yield 36%, theoretical value: 1056.97).

[0029] Synthetic Example 5: Synthesis of Compounds 136 and 140 ; The synthesis methods for 136-2 and 1-3 are the same, except that 91-1 is used to replace 1-1 and 136-1 is used to replace 1-2. MS: 348.54 (theoretical value: 348.67). The synthesis methods for 136-3 and 1-5 are the same, except that 1-3 is replaced with 136-2. MS: 360.76 (theoretical value: 360.89). The synthesis methods for 136-4 and 1-6 are the same, except that 1-5 is replaced with 136-3. MS: 550.28 (theoretical value: 550.32). The synthesis methods for 136-5 and 1-8 are the same, except that 1-6 is replaced with 136-4 and 1-7 is replaced with 91-8. MS: 961.97 (theoretical value: 962.08). Compounds 136 and 140 were synthesized using the same method as compounds 1 and 5, except that 1-8 were replaced with 136-5, resulting in compounds 136 (25% yield, MS: 908.68) and 140 (33% yield, MS: 908.78) with a theoretical value of 908.76.

[0030] Synthetic Example 6: Synthesis of Compounds 149 and 211 ; Synthesis of 149-2: In a double-necked flask under nitrogen atmosphere, 1-1 (10 mmol), 149-1 (10 mmol), and potassium carbonate (40 mmol) were dissolved in 150 mL of triethylene glycol methyl ether. The mixture was heated to 140 °C and reacted for 12 hours. After the reaction was completed and cooled, the mixture was poured into water and extracted with chloroform. The organic phases were combined, washed with water, and dried. The crude product was purified by silica gel column chromatography (hexane) to give 149-2, MS: 339.58 (theoretical value: 339.66). The synthesis method of 149-3 is the same as that of 1-5, except that 1-3 is replaced with 149-2. MS: 351.76 (theoretical value: 351.87). The synthesis method of 149-4 is the same as that of 1-6, except that 1-5 is replaced by 149-3. MS: 541.42 (theoretical value: 541.31). The synthesis method of 149-5 is the same as that of 1-8, except that 1-6 is replaced with 149-4. MS: 840.81 (theoretical value: 840.85). Compounds 149 and 211 were synthesized using the same method as compounds 1 and 5, except that 1-8 were replaced with 149-5, resulting in compounds 149 (yield 23%, MS: 787.49) and 211 (yield 21%, MS: 787.61) with a theoretical value of 787.54.

[0031] Synthetic Example 7: Synthesis of Compounds 157 and 216 ; The synthesis methods for 157-2 and 149-2 are the same, except that 149-1 is replaced with 157-1. MS value: 355.65 (theoretical value: 355.72). The synthesis method of 157-3 is the same as that of 1-5, except that 1-3 is replaced with 157-2. MS: 367.88 (theoretical value: 367.94); The synthesis method of 157-4 is the same as that of 1-6, except that 1-5 is replaced by 157-3. MS: 557.28 (theoretical value: 557.37). The synthesis method of 157-5 is the same as that of 1-8, except that 1-6 is replaced with 157-4. MS: 856.87 (theoretical value: 856.91). Compounds 157 and 216 were synthesized using the same method as compounds 1 and 5, except that 1-8 were replaced with 157-5, resulting in compounds 157 (yield 21%, MS: 803.71) and 216 (yield 25%, MS: 803.73) with a theoretical value of 803.60.

[0032] Synthetic Example 8: Synthesis of Compounds 251 and 253 ; The synthesis methods for 251-2 and 1-3 are the same, except that 91-1 is used to replace 1-1 and 251-1 is used to replace 1-1. MS value: 610.87 (theoretical value: 610.98). The synthesis method of 251-3 is the same as that of 1-5, except that 1-3 is replaced by 251-2 and 1-4 is replaced by 91-4. MS: 637.18 (theoretical value: 637.22); The synthesis method of 251-4 is the same as that of 1-6, the difference is that 1-5 is replaced by 251-3 and 1-1 is replaced by 91-1, MS: 826.54 (theoretical value: 826.66); The synthesis method of 251-5 is the same as that of 1-8, except that 1-6 is replaced with 251-4, MS: 1126.31 (theoretical value: 1126.20); Compounds 251 and 253 were synthesized using the same method as compounds 1 and 5, except that 1-8 were replaced with 251-5, resulting in compounds 251 (yield 11%, MS: 1072.78) and 253 (yield 13%, MS: 1072.76) with a theoretical value of 1072.89.

[0033] Synthetic Example 9: Synthesis of Compounds 376 and 382 ; The synthesis method of 376-2 is the same as that of 1-3, except that 1-2 is replaced with 376-1. MS: 398.87 (theoretical value: 398.93); The synthesis method of 376-3 is the same as that of 1-5, except that 1-3 is replaced with 376-2, MS: 386.65 (theoretical value: 386.72); The synthesis method of 376-4 is the same as that of 1-6, except that 1-5 is replaced with 376-3. MS: 588.28 (theoretical value: 588.37). The synthesis method of 376-5 is the same as that of 1-8, except that 1-6 is replaced with 376-4. MS: 997.86 (theoretical value: 887.91). The synthesis methods of compounds 376-6 and 382-6 are the same as those of compounds 1 and 5, except that 1-8 are replaced with 376-5 to obtain 376-6 (MS: 834.55) and 382-6 (MS: 834.53) with theoretical values ​​of 834.60. Synthesis of compound 376: 376-6 (6.0 mmol), 50 mg iodine (0.2 mmol), and 192 mg sulfur (6.0 mmol) were dissolved in 10 mL of dry o-dichlorobenzene. The mixture was bubbled under nitrogen for 5 minutes, then heated to 190°C and stirred for 72 hours. After cooling to room temperature, the system was washed with a saturated aqueous sodium sulfite solution and extracted with dichloromethane. The organic phase was evaporated to dryness under vacuum and then purified by column chromatography using a dichloromethane / petroleum ether eluent to give compound 376, yield: 35%, MS: 864.57 (theoretical value: 864.64). Compound 382 was synthesized in the same way as compound 376, except that 376-6 was replaced with 382-6. MS: 864.55 (yield 41%, theoretical value: 864.64).

[0034] Synthetic Example 10: Synthesis of Compounds 426 and 441 ; Synthesis of 426-3: In a double-necked flask under nitrogen atmosphere, 426-1 (10 mmol), 426-2 (10 mmol), tetraphenylphosphine palladium (1 mmol), and potassium carbonate (12 mmol) were added sequentially. 100 mL of a tetrahydrofuran:water mixture (1:1) was added, and the mixture was heated to 110 °C and reacted for 12 hours. After cooling, the organic phase was separated and collected. The organic phase was dried over anhydrous sodium sulfate, filtered, and concentrated. The compound was separated by silica gel column chromatography using petroleum ether:dichloromethane (4:1) as the developing solvent to obtain 426-3. MS: 317.52 (theoretical value: 317.61). The synthesis method of 426-4 is the same as that of 1-5, except that 1-3 is replaced with 426-3. MS: 329.76 (theoretical value: 329.83). The synthesis method of 426-5 is the same as that of 1-6, except that 1-5 is replaced with 426-4, MS: 519.18 (theoretical value: 519.26); The synthesis method of 426-6 is the same as that of 1-8, except that 1-6 is replaced with 426-5. MS: 818.72 (theoretical value: 818.80); The synthesis methods of compounds 426 and 441 are the same as those of compounds 1 and 5, except that 1-8 are replaced by 426-6, to obtain compounds 426 (yield 33%, MS: 765.57) and 441 (yield 29%, MS: 765.53) with a theoretical value of 765.49.

[0035] Based on the same inventive concept, embodiments of the present invention also provide an organic light-emitting device comprising the compounds of the above embodiments. The following example uses an OLED as an organic light-emitting device for illustration; however, it should be understood that the following detailed description is not a limitation of the present invention, and those skilled in the art can extend the application of the following detailed description to other organic light-emitting devices.

[0036] In one embodiment, the OLED includes a first electrode and a second electrode, and a plurality of organic material layers located between the electrodes. The organic material layers can be further divided into multiple regions. For example, the organic material layer may include a hole transport region, a light-emitting layer, and an electron transport region. In specific embodiments, a substrate can be used below the first electrode or above the second electrode. The substrate is typically made of glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. Furthermore, thin-film transistors (TFTs) can also be incorporated into the substrate used for displays. The first electrode can be formed by sputtering or depositing the material used as the first electrode on a substrate. When the first electrode is used as the anode, it can be a transparent conductive oxide material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), or any combination thereof. When the first electrode is used as the cathode, it can be a metal or alloy such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), or any combination thereof. Organic material layers can be formed on electrodes using methods such as vacuum thermal evaporation, spin coating, and printing. Compounds used as organic material layers can be small organic molecules, large organic molecules, polymers, and combinations thereof. The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a single-layer hole transport layer (HTL), including single-layer hole transport layers containing only one compound and single-layer hole transport layers containing multiple compounds. The hole transport region can also be a multilayer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL). The material for the hole transport region may be selected from, but is not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylenevinyl chloride, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives as shown in HT-1 to HT-26 below; or any combination thereof: ; ; The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more compounds from HT-1 to HT-34, or one or more compounds from HI-1 to HI-3; alternatively, one or more compounds from HT-1 to HT-34 can be doped with one or more compounds from HI-1 to HI-3. ; The light-emitting layer contains one or more light-emitting doping materials, and may also simultaneously include a host material and / or a sensitizer material. In one aspect of the invention, the host material of the light-emitting layer may be selected from, but not limited to, one or more combinations of the following H-1 to H-16: ; In one aspect of the invention, the sensitizer material of the luminescent layer can be a TADF material or a phosphorescent material, and can be selected from, but not limited to, one or more combinations of the following S-1 to S-6: ; The OLED organic material layer may also include an electron transport region between the light-emitting layer and the cathode. The electron transport region can be a single-layer electron transport layer (ETL), including single-layer electron transport layers containing only one compound and single-layer electron transport layers containing multiple compounds. The electron transport region can also be a multilayer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL). In a specific example, the electron transport layer material may be selected from, but is not limited to, one or more combinations of ET-1 to ET-31 listed below: ; ; In one example, the device may also include an electron injection layer located between the electron transport layer and the cathode, the electron injection layer material including but not limited to one or more combinations of the following: LiQ, LiF, CsF, Li2O, Cs2CO3, BaO, Na, Li and / or Ca.

[0037] To evaluate the luminescence performance of the compounds described in this invention in organic electroluminescent devices, a series of OLED devices based on multilayer organic thin film structures were designed and constructed, and the specific fabrication process is shown below:

[0038] Fabrication of Device Example 1: The glass plate coated with the ITO transparent conductive layer was ultrasonically treated in a cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone and ethanol, baked in a clean environment until all moisture was removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam. The treated ITO transparent conductive layer was placed as the anode layer 1 in the vacuum evaporation chamber. After the system reached a high vacuum, a hole injection layer 2 with a thickness of 10 nm was deposited first. This layer used a co-evaporation combination of HT-2 and HI-3 (mass ratio 97:3, w / w), with the two materials placed in different evaporation sources. Precise ratio control was achieved by adjusting the evaporation rate. This doping system aims to improve the energy level matching between the anode and the organic layer and reduce the hole injection barrier. A 15 nm thick HT-2 layer is deposited on top of the hole injection layer 2 as the hole transport layer 3. The main function of this layer is to efficiently transport holes and suppress electron back injection, maintaining a good charge balance in the device. Subsequently, a 20 nm thick HT-5 layer is deposited as the electron blocking layer 4, which aims to restrict electron penetration to the hole transport layer, thereby effectively improving the exciton binding ability and recombination efficiency in the light-emitting region. A light-emitting layer 5 with a thickness of 30 nm is deposited on the electron blocking layer 4 using a multi-source co-evaporation process. The main material is H-1, the sensitizing material is S3, and the compound 1 is the dopant material. They are placed in independent evaporation sources, and a composite light-emitting film is formed by controlling their evaporation rate ratio to 79:20:1 (w / w / w). A 30 nm thick doped system of ET-6 and LiQ (mass ratio 50:50, w / w) is deposited on the light-emitting layer 5 as an electron transport layer 6. This combination helps to improve the electron transport rate and interface injection efficiency. A 1 nm layer of LiQ was deposited on the electron transport layer 6 as the electron injection layer 7. Its extremely low work function helps to form an interfacial dipole and improves the injection efficiency of electrons from the Al cathode to the electron transport layer. An Al electrode layer with a thickness of 13 nm is deposited on top of the electron injection layer 7, which serves as the cathode layer 8. The entire organic layer and cathode evaporation process is completed in a continuous vacuum to avoid interface oxidation or contamination, with the deposition rate set to 0.1 nm / s.

[0039] In the glove box, the vapor-deposited device is coated with UV adhesive using a coating equipment. The coated cover plate is then moved to the lamination section, where the vapor-deposited substrate is placed on top of the cover plate. Finally, the substrate and cover plate are laminated using a bonding equipment and cured with UV adhesive.

[0040] Fabrication of devices in Examples 2-20: When forming the light-emitting layer, the corresponding compound in Table 1 was used to replace compound 1 in device example 1, and the organic electroluminescent device was prepared using the same method as device example 1.

[0041] Preparation of Comparative Examples 1-9: When forming the light-emitting layer, the corresponding compound in Table 1 was used to replace compound 1 in device example 1, and the organic electroluminescent device was prepared using the same method as device example 1.

[0042] The structures of ref-1 to ref-9 in Table 1 are as follows: .

[0043] The organic electroluminescent devices prepared by the above process were subjected to the following performance measurements: The voltage was increased at a rate of 0.1V per second, and the luminance of the device instance and comparative sample was measured when they reached 1000 cd / m². 2 The driving voltage was used; and the LT95 lifetime of the device was determined by a constant current aging test at room temperature with an initial brightness of 1000 cd / m², and the time it took for the brightness to decay to 95% of the initial value. The lifetime of Comparative Example 1 was used as the standard, and all others were ratios thereof. The lifetime testing system was the OLED lifetime testing system from Suzhou Fushida Scientific Instruments Co., Ltd. A photoelectric testing system integrating a Keithley 2400 source meter and spectrometer was used to perform JVL characteristics and electroluminescence spectroscopy tests on the device at room temperature. The external quantum efficiency (EQE) of the device under different driving conditions was calculated using the integrating sphere method. max Based on the luminance-current curve, locate the operating point corresponding to a luminance of 1000 cd / m², and calculate the external quantum efficiency (EQE) at that point. 1000 Efficiency roll-off is achieved through the formula: (EQE) max -EQE 1000 ) / EQE max The result, calculated by multiplying by 100%, is shown in Table 1 below: ; The above data show that the organic electroluminescent devices prepared by the compounds in the embodiments of the present invention have electroluminescence peaks distributed in the red to near-infrared band from 610 nm to 765 nm, while the full width at half maximum (FWHM) remains below 40 nm, with some embodiments showing a FWHM as low as 34 nm. Compared with comparative examples ref-1 to ref-6, which do not contain the naphthanoindolanocarbazole fused ring donor unit, the compounds of the present invention effectively reduce the optical bandgap of the material by introducing this strong electron-donating fused ring unit, achieving a significant redshift of the emission spectrum to the red band while maintaining narrow-band emission characteristics; the maximum external quantum efficiency of the devices in Examples 1 to 20 ranges from 22.8% to 34.2%, with most embodiments reaching over 30%. Under practical conditions with a brightness of 1000 cd / m², the corresponding roll-off of external quantum efficiency is controlled within the range of 16.8% to 21.5%. In contrast, the maximum external quantum efficiency of comparative examples ref-7 to ref-9 is only 26.8% to 27.7%, while their efficiency roll-off is as high as 38.9% to 67.4%. The efficiency roll-off of the devices in the embodiments is only one-third to one-quarter of that of the comparative examples. This result shows that the compounds of the present invention, through the synergistic effect of the double-B core MR framework and the sterically hindered fused ring donor, achieve red light emission while significantly suppressing intermolecular aggregation and effectively reducing nonradiative transition losses, thus exhibiting significant advantages in terms of device efficiency and efficiency roll-off. In terms of device stability, based on the LT95 lifetime of comparative example ref-1 (with a value of 1.00), the relative LT95 lifetimes of the devices in the embodiments of the present invention all reach above 1.25, with a maximum of 1.46, indicating that the operating lifetime is improved by 25% to 46% compared with the prior art. The above performance improvements are attributed to the high thermal and chemical stability brought by the rigid fused ring structure in the compounds of the present invention, and the optimization of carrier injection and transport balance by the reasonable molecular energy level design. In summary, the multi-resonance thermally activated delayed fluorescence compound provided by this invention, through the rational design of its molecular structure, successfully achieves comprehensive performance optimization of narrow-band red light emission, high external quantum efficiency, low efficiency roll-off, and long device lifetime, which is a significant improvement over existing technologies.

[0044] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., 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 compound with multiple resonance thermally activated delayed fluorescence, characterized in that, The structure is represented by general formula (I) or general formula (II): ； Rings A through H are each independently selected from one or more R-substituted or unsubstituted C6 through C6. 30 aryl, one or more R-substituted or unsubstituted C3-C 30 Mixed aromatics; X is selected from O, S, Se, NR1 or CR2R3; R, R1, R2, and R3 are each independently selected from hydrogen, deuterium, halogen, cyano, nitro, or one or more R4-substituted or unsubstituted C1-C groups. 30 Chain alkyl groups, one or more R4-substituted or unsubstituted C3~C 20 Cycloalkyl, one or more R4-substituted or unsubstituted C1~C 30 Alkoxy, one or more R4-substituted or unsubstituted C6~C 30 aryl, one or more R4-substituted or unsubstituted C3~C 30 Heteroaryl, one or more R4-substituted or unsubstituted diarylamines, one or more R4-substituted or unsubstituted C6-C 18 Arylsilyl groups are either cyclic or non-cyclic, with n being 1 to the largest substitution site on the ring. R4 groups are independently selected from hydrogen, deuterium, halogen, cyano, nitro, C1~C4. 20 Chain alkyl, C3~C 20 cycloalkyl, C1~C 20 Alkoxy, C6~C 20 Aryl, C3~C 20 Mixed aromatics; The heteroatoms in the heteroaryl group are selected from N, O, S, Se, Si, and P.

2. The multiple resonance thermally activated delayed fluorescence compound according to claim 1, characterized in that, Each of the rings A to H is independently selected from one or more R-substituted or unsubstituted C6 to C6 rings. 18 Aryl or one or more R-substituted or unsubstituted C6-C 18 Mixed aromatic compounds.

3. The multiple resonance thermally activated delayed fluorescence compound according to claim 1, characterized in that, R, R1, R2, and R3 are each independently selected from hydrogen, deuterium, or one or more R4-substituted or unsubstituted C1-C atoms. 12 Chain alkyl groups, one or more R4-substituted or unsubstituted C3~C 12 Cycloalkyl, one or more R4-substituted or unsubstituted C1~C 12 Alkoxy, one or more R4-substituted or unsubstituted C6~C 12 aryl, one or more R4-substituted or unsubstituted C3~C 12 Heteroaryl, one or more R4-substituted or unsubstituted diarylamines, one or more R4-substituted or unsubstituted C6-C 12 Arylsilyl groups are either cyclic or non-cyclic, with two adjacent substituents linked together.

4. The multiple resonance thermally activated delayed fluorescence compound according to claim 1, characterized in that, Each of the R4 atoms is independently selected from hydrogen, deuterium, C1~C1. 12 Chain alkyl, C3~C 12 cycloalkyl, C1~C 12 Alkoxy, C6~C 12 Aryl, C3~C 12 Mixed aromatic compounds.

5. The multiple resonance thermally activated delayed fluorescence compound according to claim 1, characterized in that, The specific structure of the compound is shown below: ； ； ； ； ； ； ； ； ； ； ； ； ； ； 。 6. An organic electroluminescent device, comprising an anode, a cathode, and an organic functional layer disposed between the anode and the cathode, the organic functional layer including a light-emitting layer, characterized in that, The luminescent layer comprises the resonant thermally activated delayed fluorescence compound as described in any one of claims 1 to 5.

7. The organic electroluminescent device according to claim 6, characterized in that, The resonant thermally activated delayed fluorescence compound is used as a luminescent dye and / or sensitizer in the luminescent layer.

8. A display screen or display panel, characterized in that, The display screen or display panel employs the organic electroluminescent device as described in claim 6 or 7.

9. The display screen or display panel according to claim 8, characterized in that, The display screen or display panel is an OLED display.

10. An electronic device, characterized in that, The electronic device has a display screen or display panel as described in claim 8 or 9.

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