An organic electroluminescent compound and an organic electroluminescent device

Abstract

The application provides an organic electroluminescent compound and an organic electroluminescent device. The organic electroluminescent compound is shown in formula 1. The MR-TADF green light material of the application can realize high color purity, high luminous efficiency and long service life at the same time by constructing a rigid conjugated boron-nitrogen fused ring arene structure, and effectively solves the problem that the performance of existing green light OLED materials is difficult to balance.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescence technology, and more particularly to an organic electroluminescent compound and an organic electroluminescent device. Background Technology

[0002] Organic light-emitting diodes (OLEDs), as a core research direction in the display field, are gradually becoming the mainstream development trend of next-generation display technology due to their unique technical architecture and performance advantages. Compared with traditional liquid crystal displays (LCDs) and light-emitting diode (LED) display technologies, OLED devices have irreplaceable technical advantages: their core light-emitting body is an organic layer, which is significantly simplified in thickness and weight compared to the crystal layer structure used by LCDs and LEDs, and has excellent ductility; at the same time, the lightweight nature of the OLED light-emitting layer allows for the use of flexible materials such as plastics as substrates, breaking through the technical limitations of LCDs and LEDs that rely on rigid glass substrates; in addition, OLED devices also have performance advantages such as active light emission, low start-up voltage, fast response speed, wide viewing angle, thin and light device design, and the ability to realize flexible displays, which have attracted widespread attention from academia and industry.

[0003] Full-color display is a key technical indicator for the commercial application of OLED devices, and the rational configuration of red, green, and blue primary color emitting materials is a prerequisite for achieving full-color display. Among them, green emitting materials occupy a crucial position in the full-color display system. Green emitting materials can not only directly provide the green light signal required for full-color display, but also work synergistically with red and blue emitting materials to achieve precise control over the color coordinates, color gamut, and color purity of OLED devices. This is an important foundation for ensuring the color reproduction and visual presentation effect of full-color displays. At the same time, the photoelectric performance parameters of green emitting materials directly affect the luminous efficiency, brightness, and long-term operational stability of OLED devices. The degree of energy level matching between green emitting materials and hole injection materials, electron injection materials, hole transport materials, and electron transport materials in the device is a core factor determining carrier recombination efficiency and device luminous stability, playing a decisive role in the overall performance of OLED devices.

[0004] Currently, while green luminescent materials have achieved industrial application, existing products still have shortcomings in terms of performance balance and functional compatibility: some materials, although possessing high color purity, suffer from insufficient luminous efficiency and lifespan to meet the demands of high-end applications such as high-definition displays and flexible displays; others, while performing reasonably well in terms of luminous efficiency and lifespan, suffer from poor compatibility with various functional layers of devices, leading to low carrier recombination efficiency. These technical deficiencies limit further improvements in the overall performance of OLED devices and restrict their application expansion in the high-end display field. Therefore, developing green luminescent materials that combine high color purity, high luminous efficiency, long lifespan, and excellent compatibility with various functional layers of OLED devices has become a core technological requirement for promoting the high-quality development of the OLED industry and a technical problem urgently needing to be solved in this field. Summary of the Invention

[0005] To develop organic electroluminescent materials with better device performance, this invention provides an organic electroluminescent compound, as shown in Formula 1: , In Formula 1, circles a and b, which may be identical or different, are selected from the groups shown in Formulas 2-1, 2-2, 2-3, 2-4, 2-5, and 2-6. , Where * represents the connection site, R a R b R c R d Each group is independently selected from H, D, F, substituted or unsubstituted C1-C10 straight-chain or branched alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups; m and n are integers from 0 to 4, and x and y are integers from 0 to 3; c in Formula 1 is selected from the groups shown in Formula 3: Where * represents a connection site, R e R f R g R h R i R j R k R L Each is independently selected from H, D, F, substituted or unsubstituted C1-C10 straight-chain or branched alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups; R e R f R g R h R i R j R k RL Two adjacent groups can bond with each other to form an aromatic ring or a heteroaromatic ring. The two adjacent groups refer to groups that are adjacent to each other on the same ring. The hydrogen in the aromatic ring or heteroaromatic ring can be further substituted. The substituents are selected from hydrogen, deuterium, fluorine, deuterated or undeuterated C1-C20 alkyl, C6-C20 aryl, and C5-C20 heteroaromatic.

[0006] As a preferred embodiment of the present invention, in Formula 1, circles a and b are each the same or different, selected from the following substituents: ; ; ; , Where * represents a connection site.

[0007] As a preferred embodiment of the present invention, the substituents selected from the following groups are either identical or different in circle c of Formula 1: , Where * represents a connection site.

[0008] As a preferred embodiment of the present invention, the organic electroluminescent compound is shown in Formula 4: ; Z is independently selected from: O, S, Se, Te, or directly bonded or absent; R1-R29 are independently selected from H, D, F, substituted or unsubstituted C1-C10 straight-chain or branched alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups; R 14 -R 29 Two adjacent groups can bond with each other to form an aromatic ring or a heteroaromatic ring. The two adjacent groups refer to groups that are adjacent to each other on the same ring. The substituents are selected from hydrogen, deuterium, fluorine, deuterated or undeuterated C1-C20 alkyl, C6-C20 aryl, and C5-C20 heteroaromatic.

[0009] As a preferred embodiment of the present invention, the organic electroluminescent compounds are shown in Formulas 5-18:

[0010]

[0011]

[0012]

[0013]

[0014]

[0015] , Where R1-R 29 Selected independently from H, D, F, substituted or unsubstituted C1-C10 straight-chain or branched alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups; R 14 -R 29 Two adjacent groups can bond with each other to form an aromatic ring or a heteroaromatic ring. The two adjacent groups refer to groups that are adjacent to each other on the same ring. The substituents are selected from hydrogen, deuterium, fluorine, deuterated or undeuterated C1-C20 alkyl, C6-C20 aryl, and C5-C20 heteroaromatic.

[0016] As a preferred embodiment of the present invention, R1-R in equations 5-18 13 Each of the substituents is selected from H, D, substituted or unsubstituted methyl, substituted or unsubstituted tert-butyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted diarylamino, wherein the substituent is selected from H, D, deuterated or undeuterated methyl, deuterated or undeuterated phenyl, deuterated or undeuterated tert-butyl.

[0017] As a preferred embodiment of the present invention, the organic electroluminescent compound is one of the following structural formulas:

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

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[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

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[0044]

[0045]

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[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

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[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] .

[0073] The present invention provides an organic electroluminescent device, comprising a first electrode, a second electrode, and an organic layer between the first electrode and the second electrode, wherein the organic layer contains the aforementioned organic electroluminescent compound.

[0074] In a preferred embodiment of the present invention, the organic layer comprises a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer, wherein at least one of the hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, and electron injection layer contains the aforementioned organic electroluminescent compound.

[0075] The present invention also provides an electronic display device comprising the above-described organic electroluminescent device.

[0076] Compared with the prior art, the beneficial effects of the present invention are: The MR-TADF green light material of this invention, by constructing a rigid conjugated boron-nitrogen fused-ring aromatic hydrocarbon structure, can simultaneously achieve high color purity, high luminous efficiency, and long lifespan, effectively solving the problem of the difficulty in achieving a balanced performance in existing green OLED materials. This rigid framework can suppress molecular aggregation quenching and non-radiative transitions, improve luminous quantum efficiency, and reduce device efficiency roll-off; it also enhances the material's thermal and morphological stability, significantly extending the device's operating life. Furthermore, this boron-nitrogen structured green light material exhibits excellent energy level matching with the functional layers of OLED devices, effectively promoting balanced carrier injection and efficient recombination, improving carrier recombination efficiency, thereby comprehensively optimizing the overall performance of OLED devices and better meeting the needs of high-end applications such as high-definition and flexible displays. Attached Figure Description

[0077] Figure 1 This is a schematic diagram of the structure of the organic electroluminescent device of the present invention; The labels in the diagram represent: 1-anode, 2-hole injection layer, 3-first hole transport layer, 4-second hole transport layer, 5-light-emitting layer, 6-hole blocking layer, 7-electron transport layer, 8-electron injection layer, and 9-cathode.

[0078] Figure 2 This is an HPLC chromatogram of compound 1 prepared by synthesis example 1 of the present invention.

[0079] Figure 3 The DSC spectrum of compound 1 prepared in Synthesis Example 1 of this invention is shown below. Figure 3 It can be seen that the Tg value of compound 1 is 117.19 ℃.

[0080] Figure 4 The TGA spectrum of compound 1 prepared in Synthesis Example 1 of this invention is shown below. Figure 4 It can be seen that the Td value of compound 1 is 447.62℃. Detailed Implementation

[0081] Embodiments of various aspects are further illustrated and described below. It should be understood that the description herein is not intended to limit the claims to the specific aspects described. Rather, it is intended to cover substitutions, modifications, and equivalents that may be included within the spirit and scope of this disclosure as defined by the appended claims.

[0082] As used herein, in the terms “deuterated” and “undeuterated,” the term “deuterated” means that at least one hydrogen in the group is recoordinated with deuterium. The term “undeuterated” means that none of the hydrogens in the group are recoordinated with deuterium.

[0083] In this document, "aromatic group," "aryl," or "aromatic group" refers to a group containing one or more aromatic rings, including but not limited to benzene, naphthalene, phenanthrene, fluorene, acenaphthene, pyridine, pyrrole, furan, thiophene, etc. In C6-C30 aromatic groups, C6-C30 means that the group contains 6-30 carbon atoms. In C1-C10 alkyl-substituted C6-C20 aromatic groups, C1-C10 refers to the number of carbon atoms in the substituent, and C6-C20 refers to the number of carbon atoms in the unsubstituent aromatic group. Aromatic groups can be divided into monocyclic aryl and polycyclic aryl groups. Specific aromatic groups in this invention include, but are not limited to, phenyl, biphenyl, terphenyl, anthracene, naphthyl, phenanthrene, fluorenyl, dibenzofuranyl, dibenzothiophene, 9,9-spirodifluorenyl, 9,9-dimethylfluorenyl, or 9,9-diphenylfluorenyl, etc. Aromatic groups can be substituted or unsubstituted.

[0084] In this article, "deuterated methyl" refers to any one of monodeuterated methyl, dideuterated methyl, or trideuterated methyl.

[0085] In this article, "heteroaryl" refers to a heteroaryl group obtained by replacing one or more C atoms in the structure of "aryl" with one or more heteroatoms (such as N, O or S).

[0086] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0087] Synthesis example 1: Compound 1

[0088]

[0089] Procedure and post-treatment: Under nitrogen protection, compound 1-a (1 eq, 20.00 g, 321.95 g / mol, 62.12 mmol), compound (2 eq, 34.68 g, 279.20 g / mol, 124.24 mmol), cesium carbonate (2 eq, 40.48 g, 325.82 g / mol, 124.24 mmol), and N,N-dimethylformamide (200 mL) were added to a reaction flask. After the addition was complete, the reaction was carried out at room temperature for 12 h. After the reaction was complete, 500 mL of water was added and stirred for 15 min. After all the solid precipitated, the solid was filtered to obtain a white solid. After purification by column chromatography, compound 1-c (51.66 g, yield 91.2%) was obtained, MS (EI): 840.79 (M+).

[0090]

[0091] Procedure and post-treatment: Under nitrogen protection, compound 1-d (1 eq, 50.00 g, 840.79 g / mol, 59.46 mmol) and tetrahydrofuran (2 L) were added to the reaction flask. The mixture was cooled to -78 °C, and a solution of n-butyllithium hexane (1.1 eq, 2.5 M, 26.16 mL, 65.41 mmol) was slowly added dropwise. After the addition was complete, the mixture was stirred at -78 °C for 2 h. After stirring was complete, a tetrahydrofuran solution (200 mL) of compound (1.5 eq, 26.08 g, 292.42 g / mol, 89.19 mmol) was slowly added dropwise. The mixture was slowly restored to room temperature and stirred for 12 h. After the reaction was complete, the mixture was cooled to 0 °C, and a 1 M hydrochloric acid aqueous solution (100 mL) was slowly added to quench the reaction. 400 mL of water was added, and the mixture was extracted three times with 1 L × 3 dichloromethane. The organic phases were combined, dried with anhydrous sodium sulfate, filtered, and then distilled under reduced pressure. The crude product was dissolved in dichloromethane (5 L), and 47% boron trifluoride diethyl ether solution (20 mL) was slowly added at room temperature. The reaction was carried out at room temperature for 12 h. After the reaction was completed, 500 mL of saturated sodium bicarbonate aqueous solution was slowly added, and the mixture was extracted three times with 1 L × 3 dichloromethane. The organic phases were combined, dried with anhydrous sodium sulfate, filtered, and then distilled under reduced pressure. The product was purified by column chromatography to obtain compound 1-e (35.86 g, yield 49.5%), MS (EI): 1231.81 (M+).

[0092]

[0093] Procedure and post-treatment: Under nitrogen protection, compound 1-e (1 eq, 35.00 g, 1231.81 g / mol, 28.41 mmol) and chloroform (2 L) were added to the reaction flask, cooled to 0 °C, and N-bromosuccinimide (1.5 eq, 7.58 g, 177.98 g / mol, 42.61 mmol) was added in portions. The mixture was then slowly restored to room temperature and stirred for 12 h. After the reaction was completed, the mixture was distilled under reduced pressure and purified by column chromatography to obtain compound 1-f (35.35 g, yield 92.7%), MS (EI): 1310.71 (M+).

[0094]

[0095] Procedure and post-treatment: Under nitrogen protection, compound 1-f (1 eq, 35.00 g, 1310.71 g / mol, 26.70 mmol) was added to tert-butylbenzene (500 mL), and the mixture was cooled to -78 °C. A hexane solution of n-butyllithium (1.1 eq, 2.5 M, 11.74 mL, 29.37 mmol) was slowly added dropwise. After the addition was complete, the mixture was brought back to room temperature and stirred for 2 h. Then, the mixture was cooled to -78 °C again, and boron tribromide (2 eq, 13.37 g, 250.52 g / mol, 53.40 mmol) was slowly added. After stirring for 50 min, N,N-diisopropylamine (2 eq, 5.40 g, 101.19 g / mol, 53.40 mmol) was slowly added. The mixture was then heated to 140 °C and reacted for 12 minutes. After h, the mixture was cooled to room temperature, and the reaction solution was slowly poured into an ice-water mixture to quench it. The organic phase was separated, dried with anhydrous magnesium sulfate, and then evaporated to dryness. After purification by column chromatography, the compound (12.57 g, yield 38.2%) was obtained, MS (EI): 1239.60 (M+).

[0096]

[0097] Procedure and post-treatment: Under nitrogen protection, compound 1-g (1 eq, 12.00 g, 1239.60 g / mol, 9.68 mmol), ferric chloride (1 eq, 1.57 g, 162.2 g / mol, 9.68 mmol), and dichloromethane (5 L) were added to a reaction flask. Nitromethane (200 mL) was slowly added dropwise at room temperature, and the reaction was allowed to proceed for 24 h at room temperature. After the reaction was complete, 500 mL of saturated sodium bicarbonate solution was slowly added. The mixture was extracted three times with 1 L × 3 dichloromethane solutions. The combined organic phases were dried over anhydrous sodium sulfate, filtered, and distilled under reduced pressure. The purified compound 1 (5.38 g, yield 45.3%) was obtained by column chromatography. ESI-MS (M+) (m / z): theoretical value 1236.74, measured value 1236.62. Molecular formula C 92 H 93 BN2.

[0098] Synthesis Example 2: Compound 8

[0099]

[0100]

[0101]

[0102]

[0103]

[0104] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 8 (yield 43.1%). ESI-MS (m / z) (M+): theoretical value 844.30, measured value 844.35, molecular formula C 64 H 37 BN2.

[0105] Synthesis Example 3: Compound 18

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[0107]

[0108]

[0109]

[0110]

[0111] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 18 (yield 42.9%). ESI-MS (m / z) (M+): theoretical value 900.37, measured value 900.41, molecular formula C 68 H 45 BN2.

[0112] Synthesis Example 4: Compound 22

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[0117]

[0118] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 22 (yield 46.3%). ESI-MS (m / z) (M+): theoretical value 856.372, measured value 856.326, molecular formula C 64 H 25 D 12 BN2.

[0119] Synthesis Example 5: Compound 28

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[0125] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 28 (yield 42.8%). ESI-MS (m / z) (M+): theoretical value 1316.62, measured value 1316.49, molecular formula C 100 H 77 BN2.

[0126] Synthesis Example 6: Compound 40

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[0131]

[0132] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 40 (yield 44.4%). ESI-MS (m / z) (M+): theoretical value 924.51, measured value 924.43, molecular formula C 68 H 35 D 24 BN2.

[0133] Synthesis Example 7: Compound 47

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[0135]

[0136]

[0137]

[0138]

[0139] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 47 (yield 43.9%). ESI-MS (m / z) (M+): theoretical value 1240.77, measured value 1240.62, molecular formula C 92 H 97 BN2.

[0140] Synthesis Example 8: Compound 68

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[0142]

[0143]

[0144]

[0145]

[0146] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 68 (yield 44.2%). ESI-MS (m / z) (M+): theoretical value 860.41, measured value 860.49, molecular formula C 64 H 29 D 12 BN2.

[0147] Synthesis Example 9: Compound 86

[0148]

[0149]

[0150]

[0151]

[0152]

[0153] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 86 (yield 45.3%). ESI-MS (m / z) (M+): theoretical value 928.54, measured value 928.43, molecular formula C 68 H 39 D 24 BN2.

[0154] Synthesis Example 10: Compound 93

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[0156]

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[0159]

[0160] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 93 (yield 42.6%). ESI-MS (m / z) (M+): theoretical value 1238.76, measured value 1238.56, molecular formula C 92 H 95 BN2.

[0161] Synthesis Example 11: Compound 120

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[0167] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 120 (yield 43.4%). ESI-MS (m / z) (M+): theoretical value 1319.64, measured value 1319.56, molecular formula C 100 H 79 BN2.

[0168] Synthesis Example 12: Compound 138

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[0174] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 138 (yield 42.4%). ESI-MS (m / z) (M+): theoretical value 860.41, measured value 860.27, molecular formula C 60 H 29 D 12 BN2.

[0175] Synthesis Example 13: Compound 144

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[0177]

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[0180]

[0181] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 144 (yield 43.5%). ESI-MS (m / z) (M+): theoretical value 1091.46, measured value 1091.41, molecular formula C 77 H 64 BN2S2.

[0182] Synthesis Example 14: Compound 148

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[0184]

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[0188] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 148 (yield 42.7%). ESI-MS (m / z) (M+): theoretical value 907.30, measured value 907.86, molecular formula C 65 H 40 OBN2S.

[0189] Synthesis Example 15: Compound 152

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[0195] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 152 (yield 43.1%). ESI-MS (m / z) (M+): theoretical value 1140.61, measured value 1140.69, molecular formula C 84 H 77 OBN2.

[0196] Synthesis Example 16: Compound 158

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[0202] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 158 (yield 45.7%). ESI-MS (m / z) (M+): theoretical value 860.30, measured value 860.36, molecular formula C 64 H 37 OBN2.

[0203] Synthesis Example 17: Compound 165

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[0209] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 165 (yield 43.4%). ESI-MS (m / z) (M+): theoretical value 804.24, measured value 804.21, molecular formula C 60 H 29 OBN2.

[0210] Synthesis Example 18: Compound 171

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[0212]

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[0216] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 171 (yield 39.8%). ESI-MS (m / z) (M+): theoretical value 906.44, measured value 906.41, molecular formula C 66 H 23 D 18 OBN2.

[0217] Synthesis Example 19: Compound 177

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[0219]

[0220]

[0221]

[0222]

[0223] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 177 (yield 43.1%). ESI-MS (m / z) (M+): theoretical value 874.39, measured value 874.35, molecular formula C 64 H27 D 12 OBN2.

[0224] Synthesis Example 20: Compound 185

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[0226]

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[0230] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 185 (yield 44.2%). ESI-MS (m / z) (M+): theoretical value 1078.54, measured value 1078.52, molecular formula C 78 H 59 D6BN2S.

[0231] Synthesis Example 21: Compound 193

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[0237] Process and post-processing: The preparation method was basically the same as in Example 1. The reaction yielded compound 193 (yield 46.1%). ESI-MS (m / z) (M+): theoretical value 910.35, measured value 910.37, molecular formula C 66 H 35 D6BN2S.

[0238] Synthesis Example 22: Compound 199

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[0240]

[0241]

[0242]

[0243]

[0244] Process and post-processing: The preparation method is basically the same as in Example 1. The reaction yielded compound 199 (yield 39.3%). ESI-MS (m / z) (M+): theoretical value 1040.41, measured value 1040.48, molecular formula C76H33D12BN2S.

[0245] Material performance testing.

[0246] Thermogravimetric temperature (Td) and glass transition temperature (Tg) of compound 1 prepared by synthesis example 1 of this invention were tested. The Td was measured at a mass loss of 5% in a nitrogen atmosphere using a TGAN-1000 thermogravimetric analyzer at a nitrogen flow rate of 10 mL / min. The Tg was measured by differential scanning calorimetry (DSC, Shinco DSCN-650) at a heating rate of 10 °C / min. The test results are as follows: Figure 3 , Figure 4 As shown, the glass transition temperature (Tg) of compound 1 is 117.19℃, and the thermogravimetric temperature (Td) of compound 1 is 447.62℃. The above test results indicate that the compound prepared by the synthesis example of this invention has a high Td value and a suitable glass transition temperature. Therefore, the compound of this invention has excellent thermal stability, meeting the requirements for vapor deposition and use as an organic electroluminescent compound.

[0247] Device performance testing.

[0248] Application Example 1: ITO / Ag / ITO is used as the anode substrate material, and its surface is treated sequentially with water, acetone, and N2 ions. A hole injection layer (HIL) is formed by depositing 10 nm of HT1 doped with 3% NDP-9 on top of the ITO / Ag / ITO anode substrate. A first hole transport layer (HTL) is formed by vacuum evaporating 100 nm of HT1 above the hole injection layer (HIL); A second hole transport layer (GPL) is formed by vacuum evaporating 40 nm of GP-1 above the first hole transport layer (HTL); GH-1 as the light-emitting host material, GD-1 as the first light-emitting dopant material (GD-1 doping ratio 2%), and Compound 1 of the present invention as the second light-emitting dopant material (Compound 1 doping ratio 0.5%) are co-deposited on the second hole transport layer (GPL) to form a light-emitting layer (EML) with a thickness of 40 nm. HB-1 was deposited onto the light-emitting layer (EML) to obtain a hole blocking layer (HBL) with a thickness of 5 nm. ET-1 and LiQ were co-deposited onto the hole blocking layer (HBL) in a 5:5 ratio to obtain an electron transport layer (ETL) with a thickness of 30 nm. Ytterbium (Yb) is vapor-deposited onto a hole blocking layer (HBL) to form an electron injection layer (EIL) with a thickness of 1 nm; Magnesium (Mg) and silver (Ag) are mixed in a 1:9 ratio and vapor-deposited onto the electron injection layer (EIL) to form a cathode with a thickness of 12 nm. A CP-1 layer with a thickness of 60 nm is deposited on the cathode sealing layer to form a light extraction layer (CPL). Finally, the device surface is sealed with a UV-curable adhesive and a sealing film containing a desiccant to protect the organic electroluminescent device from the influence of oxygen or moisture in the atmosphere. Thus, the organic electroluminescent device is prepared.

[0249]

[0250]

[0251] Application Example 2-22 Compounds 8, 18, 22, 28, 40, 47, 68, 86, 93, 120, 138, 144, 148, 152, 158, 165, 171, 177, 185, 193, and 199, prepared in Synthesis Examples 2-22 of this invention, were used as the second doping materials for the light-emitting layer. The remaining parts were the same as in Application Example 1, thereby preparing the organic electroluminescent devices of Application Examples 2-22.

[0252] Comparative Examples 1-4: Compounds D1, D2, D3, and D4 were used as the second doping materials of the luminescent layer, respectively, and the rest were the same as in Application Example 1, thus forming Comparative Examples 1-4.

[0253]

[0254]

[0255] The organic electroluminescent devices prepared in Application Examples 1-22 and Comparative Examples 1-4 were subjected to device performance tests at a current density of 10 mA / cm². 2 The measurements were performed under the specified conditions, and the test results are shown in Table 1 below.

[0256] Table 1

[0257] As shown in Table 1 above, when the compounds of the present invention are applied to organic electroluminescent devices, the luminous efficiency is significantly improved at the same current density, the device start-up voltage is reduced, and the device performance is effectively improved.

[0258] The organic electroluminescent devices prepared in Comparative Examples 1-4 and Application Examples 1-10 of this invention were subjected to lifetime tests to obtain the luminescence lifetime T97% data (the time for the luminescence brightness to drop to 97%). The testing equipment was a TEO light-emitting device lifetime testing system. The test results are shown in Table 2 below: Table 2

[0259] As shown in Table 2 above, when the compounds of this invention are applied to organic electroluminescent devices, the device lifetime of the organic electroluminescent devices prepared with the compounds of this invention is improved at the same current density. Combined with Table 1, the organic electroluminescent devices prepared with the compounds of this invention show improvements in start-up voltage, luminous efficiency, and lifetime, and have broad application prospects.

[0260] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

[0261] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An organic electroluminescent compound, characterized in that, As shown in Equation 1: ， In Formula 1, circles a and b, which may be identical or different, are selected from the groups shown in Formulas 2-1, 2-2, 2-3, 2-4, 2-5, and 2-6. ， Where * represents the connection site, R a R b R c R d Each group is independently selected from H, D, F, substituted or unsubstituted C1-C10 straight-chain or branched alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups; m and n are integers from 0 to 4, and x and y are integers from 0 to 3; c in Formula 1 is selected from the groups shown in Formula 3: ， Where * represents the connection site, R e R f R g R h R i R j R k R L Each is independently selected from H, D, F, substituted or unsubstituted C1-C10 straight-chain or branched alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups; R e R f R g R h R i R j R k R L Two adjacent groups can bond with each other to form an aromatic ring or a heteroaromatic ring. The two adjacent groups refer to groups that are adjacent to each other on the same ring. The hydrogen in the aromatic ring or heteroaromatic ring can be further substituted. The substituents are selected from hydrogen, deuterium, fluorine, deuterated or undeuterated C1-C20 alkyl, C6-C20 aryl, and C5-C20 heteroaromatic.

2. The organic electroluminescent compound according to claim 1, characterized in that, In Formula 1, circles a and b, which may be identical or different, are selected from the following substituents: ； ； ， Where * represents a connection site.

3. The organic electroluminescent compound according to claim 1, characterized in that, In Formula 1, the same or different c in circle 1 are selected from the following substituents: ， Where * represents a connection site.

4. The organic electroluminescent compound according to claim 1, characterized in that, Organic electroluminescent compounds are shown in Formula 4: ； Where Z is independently selected from: O, S, Se, Te, or directly bonded or absent; R1-R29 are independently selected from H, D, F, substituted or unsubstituted C1-C10 straight-chain or branched alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups; R 14 -R 29 Two adjacent groups can bond with each other to form an aromatic ring or a heteroaromatic ring. The two adjacent groups refer to groups that are adjacent to each other on the same ring. The substituents are selected from hydrogen, deuterium, fluorine, deuterated or undeuterated C1-C20 alkyl, C6-C20 aryl, and C5-C20 heteroaromatic.

5. The organic electroluminescent compound according to claim 1, characterized in that, Organic electroluminescent compounds are shown in Formulas 5-18: ； ； ； ； ； ； ， Among them, R1-R 29 Selected independently from H, D, F, substituted or unsubstituted C1-C10 straight-chain or branched alkyl groups, substituted or unsubstituted C6-C30 aryl groups, and substituted or unsubstituted C5-C30 heteroaryl groups; R 14 -R 29 Two adjacent groups can bond with each other to form an aromatic ring or a heteroaromatic ring. The two adjacent groups refer to groups that are adjacent to each other on the same ring. The substituents are selected from hydrogen, deuterium, fluorine, deuterated or undeuterated C1-C20 alkyl, C6-C20 aryl, and C5-C20 heteroaromatic.

6. The organic electroluminescent compound according to claim 5, characterized in that, In equations 5-18, R1-R 13 Each of the substituents is selected from H, D, substituted or unsubstituted methyl, substituted or unsubstituted tert-butyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted diarylamino, wherein the substituent is selected from H, D, deuterated or undeuterated methyl, deuterated or undeuterated phenyl, deuterated or undeuterated tert-butyl.

7. The organic electroluminescent compound according to claim 1, characterized in that, The organic electroluminescent compound is one of the following structural formulas: ； ； ； ； ； ； ； ； ； ； 8. An organic electroluminescent device, characterized in that, It includes a first electrode, a second electrode, and an organic layer between the first electrode and the second electrode, wherein the organic layer contains an organic electroluminescent compound as described in any one of claims 1-7.

9. An organic electroluminescent device according to claim 8, characterized in that, The organic layer comprises a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer, wherein at least one of the hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, and electron injection layer contains an organic electroluminescent compound as described in any one of claims 1-7.

10. An electronic display device, characterized in that, It contains the organic electroluminescent device as described in claim 8.

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