An organic electroluminescent compound and an organic electroluminescent device

Abstract

The application provides an organic electroluminescent compound characterized in that it is shown as formula 1: The multiple resonance thermally activated delayed fluorescence (MR-TADF) green light emitting material and device provided by the application realizes narrow-band green light emission based on a multiple resonance effect, has high color purity, can accurately match high color gamut display standards, has a small singlet-triplet energy level difference, a fast reverse intersystem crossing rate, an exciton utilization rate close to 100%, and a significantly improved device external quantum efficiency, a rigid conjugated skeleton can effectively inhibit intermolecular pi-pi stacking and quenching, greatly reduce the efficiency roll-off under high brightness, improve the working stability and service life of the device, and has good matching with red light and blue light emitting materials, and can effectively solve the problem that the efficiency, color purity and service life of the green light emitting material in the existing full-color OLED display are 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] The demands on the color purity, luminous efficiency, stability, and cost of luminescent materials for full-color OLED displays are constantly increasing. Green luminescent materials, as a crucial factor affecting the color gamut, brightness, and lifespan of OLEDs, are no longer adequately supported by existing commercially available materials. First-generation fluorescent materials suffer from low exciton utilization and insufficient luminous efficiency; while noble metal phosphorescent materials offer higher efficiency, they suffer from high raw material costs, resource scarcity, broad spectrum, and poor color purity; conventional thermally activated delayed fluorescence (TADF) materials generally exhibit technical bottlenecks such as large half-peak width, severe efficiency roll-off at high brightness, and easy molecular quenching, failing to meet the commercialization requirements of high color gamut standards like BT.2020. Summary of the Invention

[0003] To develop organic electroluminescent materials with better device performance, this invention provides an organic electroluminescent compound, as shown in Formula 1: , In Formula 1, X is selected from O, N, S, Se; rings a and b, which may be the same or different, are selected from H, D, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, and substituted or unsubstituted amino groups. At least one of rings a and b in Formula 1 is a substituted or unsubstituted nitrogen-containing heteroaryl or a substituted or unsubstituted amino group; R1-R 11 Each of the following is independently selected from H, D, F, substituted or unsubstituted C1-C10 straight-chain or branched alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C5-C30 heteroaryl; the substituent is selected from hydrogen, deuterium, fluorine, deuterated or undeuterated C1-C20 alkyl, deuterated or undeuterated C6-C20 aryl, deuterated or undeuterated C5-C20 heteroaryl.

[0004] In a preferred embodiment of the present invention, in Formula 1, rings a and b, which may be the same or different, are selected from H, D, substituted or unsubstituted phenyl, substituted or unsubstituted diarylamine, substituted or unsubstituted carbazole; the substituents are selected from H, D, F, deuterated or undeuterated C1-C20 alkyl, deuterated or undeuterated C6-C20 aryl, deuterated or undeuterated C5-C20 heteroaryl, and at least one of rings a and b is a substituted or unsubstituted nitrogen-containing heteroaryl or a substituted or unsubstituted amine.

[0005] In a preferred embodiment of the present invention, in Formula 1, ring a and ring b, which may be the same or different, are selected from the following groups: ; Ra is independently selected from deuterated or undeuterated C1-C20 alkyl groups, deuterated or undeuterated C6-C20 aryl groups, x is independently selected from integers from 0 to 5, y is independently selected from integers from 0 to 4, and at least one of ring a and ring b is a substituted or unsubstituted nitrogen-containing heteroaryl group or a substituted or unsubstituted amino group.

[0006] In a preferred embodiment of the present invention, in Formula 1, ring a and ring b, which may be the same or different, are selected from the following groups: , Where * represents a linking site, and at least one of ring a and ring b is a substituted or unsubstituted nitrogen-containing heteroaryl group or a substituted or unsubstituted amino group.

[0007] As a preferred embodiment of the present invention, the organic electroluminescent compound is shown in Formulas 2-4: , Where R1-R 13 Each of the following is independently selected from H, D, F, substituted or unsubstituted C1-C10 straight-chain or branched alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C5-C30 heteroaryl; the substituent is selected from hydrogen, deuterium, fluorine, deuterated or undeuterated C1-C20 alkyl, deuterated or undeuterated C6-C20 aryl, deuterated or undeuterated C5-C20 heteroaryl; L1 and L2 are each independently selected from substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C5-C30 heteroaryl; a and b are each independently selected from 0 or 1; Ar1, Ar2, Ar3, and Ar4 are each independently selected from substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C5-C30 heteroaryl, Ar1 and Ar2 can be linked to form a ring, and Ar3 and Ar4 can be linked to form a ring.

[0008] As a preferred embodiment of the present invention, the organic electroluminescent compound is one of the following structural formulas: .

[0009] The present invention also 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 an organic electroluminescent compound as described in any one of claims 1-6.

[0010] As 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 an organic electroluminescent compound as described in any one of claims 1-6.

[0011] As a preferred embodiment of the present invention, the light-emitting layer contains an organic electroluminescent compound as described in any one of claims 1-6.

[0012] The present invention also provides an electronic display device comprising the organic electroluminescent device as described in claim 7.

[0013] Compared with the prior art, the beneficial effects of the present invention are: The multiple resonance thermally activated delayed fluorescence (MR-TADF) green emitting material and device described in this invention are innovatively designed to address the shortcomings of existing technologies. Their application in full-color OLED displays offers significant technical advantages: narrow-band green light emission is achieved based on the multiple resonance effect, resulting in high color purity and precise matching with high color gamut display standards; a small singlet-triplet energy level difference and a fast reverse intersystem crossing rate lead to near 100% exciton utilization, significantly improving the external quantum efficiency of the device; the rigid conjugated framework effectively suppresses intermolecular π-π stacking and quenching, greatly reducing efficiency roll-off at high brightness and improving device stability and lifespan; furthermore, the material is free of precious metals, ensuring good device process compatibility and compatibility with red and blue emitting materials, making it suitable for high-resolution, flexible display devices. It effectively solves the problem of balancing efficiency, color purity, and lifespan in existing full-color OLED displays, demonstrating outstanding commercial value. Attached Figure Description

[0014] 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.

[0015] Figure 2 This is an HPLC chromatogram of compound 1 prepared by synthesis example 1 of the present invention.

[0016] 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 113.52℃.

[0017] 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 437.71℃. Detailed Implementation

[0018] 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.

[0019] 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.

[0020] 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.

[0021] In this article, "deuterated methyl" refers to any one of monodeuterated methyl, dideuterated methyl, or trideuterated methyl.

[0022] 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).

[0023] 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.

[0024] Synthesis example 1: Compound 1 .

[0025] S1: .

[0026] Procedure and post-treatment: Under nitrogen protection, compound 1-a (2 eq, 20.00 g, 235.91 g / mol, 84.77 mmol), compound 1-b (1 eq, 11.84 g, 279.43 g / mol, 42.38 mmol), sodium tert-butoxide (2 eq, 8.15 g, 96.1 g / mol, 84.77 mmol), tris(dibenzylacetone)dipalladium (0.05 eq, 1.94 g, 915.72 g / mol, 2.12 mmol), tri-tert-butylphosphine (0.1 eq, 0.85 g, 202.32 g / mol, 4.23 mmol), and toluene (500 mL) were added to a reaction flask. After the addition was complete, the reaction was carried out at 110 °C for 12 h. After the reaction was completed, the mixture was cooled to room temperature and then 10 mL of toluene was added. After stirring with mL of water for 15 min, the mixture was filtered to obtain a filtrate. The filtrate was filtered through diatomaceous earth and separated to obtain an organic phase. The organic phase was dried with anhydrous magnesium sulfate and then evaporated to dryness. After purification by column chromatography, compound 1-c (14.57 g, yield 79.4%) was obtained, MS (EI): 433.14 (M+).

[0027] S2: .

[0028] Procedure and post-treatment: Under nitrogen protection, compound 1-c (1 eq, 14.50 g, 434.42 g / mol, 33.38 mmol), compound 1-d (1 eq, 8.22 g, 246.17 g / mol, 33.38 mmol), sodium tert-butoxide (2 eq, 6.41 g, 96.1 g / mol, 66.76 mmol), tris(dibenzylacetone)palladium (0.05 eq, 1.52 g, 915.72 g / mol, 1.66 mmol), tri-tert-butylphosphine (0.1 eq, 0.67 g, 202.32 g / mol, 3.33 mmol), and toluene (500... The solution was added to the reaction flask in mL. After the addition was complete, the reaction was carried out at 110℃ for 12 h. After the reaction was completed, the solution was cooled to room temperature, 10 mL of water was added, and the mixture was stirred for 15 min. The solution was then filtered to obtain the filtrate. The filtrate was filtered through diatomaceous earth and separated to obtain the organic phase. The organic phase was dried with anhydrous magnesium sulfate and then evaporated to dryness. After purification by column chromatography, compound 1-e (15.01 g, yield 75.1%) was obtained, MS (EI): 600.20 (M+).

[0029] S3: .

[0030] Procedure and post-treatment: Under nitrogen protection, compound 1-e (1 eq, 15.00 g, 599.68 g / mol, 25.00 mmol), compound 1-f (1 eq, 9.97 g, 398.98 g / mol, 25.00 mmol), potassium carbonate (2 eq, 6.91 g, 138.21 g / mol, 50.00 mmol), copper powder (1 eq, 1.59 g, 63.55 g / mol, 25.00 mmol), and o-dichlorobenzene (200 mL) were added to a reaction flask. After the addition was complete, the reaction was carried out at 180 °C for 24 h. After the reaction was completed, the mixture was cooled to room temperature, and 10 mL of water was added. The mixture was stirred for 15 min and then filtered to obtain the filtrate. The filtrate was filtered through diatomaceous earth and the organic phase was separated. The organic phase was dried over anhydrous magnesium sulfate and then evaporated to dryness. After purification by column chromatography, compound 1-g was obtained. (18.93g, yield 87.4%), MS (EI): 870.16 (M+).

[0031] S4: .

[0032] Procedure and post-treatment: Compound 1-g (1 eq, 18.00 g, 870.75 g / mol, 20.00 mmol) was added to a 100 mL solution of sodium hydroxide (5 eq, 4.00 g, 39.99 g / mol, 100.00 mmol) in ethanol:water (volume ratio 1:1). After the addition was complete, the mixture was refluxed for 24 h. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was concentrated to half. Concentrated hydrochloric acid was added to acidify the mixture until a large amount of solid precipitated. The solid was filtered off, washed with a large amount of water, and dried under vacuum to obtain compound 1-h (16.5 g, yield 98.0%), MS (EI): 842.69 (M+).

[0033] S5: .

[0034] Procedure and post-treatment: Compound 1-h (1 eq, 16.50 g, 842.69 g / mol, 20.00 mmol) was dissolved in 200 mL of ultradry dichloromethane. Oxaloyl chloride (2.2 eq, 5.58 g, 126.93 g / mol, 44.00 mmol) and two drops of ultradry DMF were added. After the addition was complete, the mixture was refluxed for 1 h. Then, tin tetrachloride (2.2 eq, 12.25 g, 278.53 g / mol, 44.00 mmol) was added, and the mixture was refluxed for another 6 h. After the reaction was complete, the mixture was cooled to room temperature, and 1 M sodium hydroxide aqueous solution was added dropwise until the solution was neutral. The mixture was extracted three times with dichloromethane. The organic phase was dried over anhydrous magnesium sulfate and then evaporated to dryness. After purification by column chromatography, compound 1-i (12.10 g, yield 75.2%) was obtained, MS (EI): 806.10 (M+).

[0035] S6: .

[0036] Procedure and post-treatment: Under nitrogen protection, compound 1-i (1 eq, 12.00 g, 806.66 g / mol, 14.88 mmol), compound 1-j (1 eq, 4.21 g, 282.97 g / mol, 14.88 mmol), potassium carbonate (2 eq, 4.11 g, 138.21 g / mol, 29.76 mmol), tetraphenylphosphine palladium (0.05 eq, 0.85 g, 1155.56 g / mol, 0.74 mmol), and 200 mL of a toluene:water mixture (1:1 volume) were added to a reaction flask. After the addition was complete, the reaction was carried out at 110 °C for 12 h. After the reaction was completed, the mixture was cooled to room temperature and extracted three times with dichloromethane. The organic phase was dried over anhydrous magnesium sulfate and then evaporated to dryness. After purification by column chromatography, compound 1-k (11.95 g / mol, 14.88 mmol) was obtained. g, yield 90.9%, MS (EI): 882.14 (M+).

[0037] S7: .

[0038] Procedure and post-treatment: Under nitrogen protection, compound 1-k (1 eq, 10.59 g, 882.76 g / mol, 12.00 mmol), compound 1-l (2 eq, 6.71 g, 279.43 g / mol, 24.00 mmol), sodium tert-butoxide (2 eq, 2.31 g, 96.1 g / mol, 24.00 mmol), tris(dibenzylacetone)palladium (0.05 eq, 1.10 g, 915.72 g / mol, 1.20 mmol), tri-tert-butylphosphine (0.1 eq, 0.48 g, 202.32 g / mol, 2.40 mmol), and toluene (200 mg / mol) were disposed of in a nitrogen atmosphere. (mL) was added to the reaction flask. After the addition was complete, the reaction was carried out at 110℃ for 12 h. After the reaction was completed, the mixture was cooled to room temperature, and 10 mL of water was added. The mixture was stirred for 15 min and then filtered to obtain the filtrate. The filtrate was filtered through diatomaceous earth and the organic phase was separated. The organic phase was dried with anhydrous magnesium sulfate and then evaporated to dryness. After purification by column chromatography, compound 1 (8.56 g, yield 66.0%) was obtained. ESI-MS (m / z) (M+): theoretical value 1081.41, measured value 1081.52. Elemental analysis results (molecular formula C) 72 H 63 O2N3Se): Theoretical values: C, 79.98 H, 5.87 O, 2.96 N, 3.89 Se, 7.30; Measured values: C, 79.91 H, 5.89 O, 2.98 N, 3.88 Se, 7.34.

[0039] Synthesis example 2: Compound 15 .

[0040] Synthesis steps: .

[0041] Process and post-processing: The preparation method was basically the same as that of Synthesis Example 1. The reaction yielded compound 15 (yield 22.1%). ESI-MS (m / z) (M+): theoretical value 1075.36, measured value 1075.29. Elemental analysis results (molecular formula C...) 72 H 57 O2N3Se).

[0042] Synthesis example 3: Compound 30 .

[0043] Synthesis steps: .

[0044] Process and post-processing: The preparation method was basically the same as in Synthesis Example 1. The reaction yielded compound 30 (yield 20.9%). ESI-MS (m / z) (M+): theoretical value 768.13, measured value 768.09. Elemental analysis results (molecular formula C...) 50 H 28 O2N2Se).

[0045] Synthesis example 4: Compound 45 .

[0046] Synthesis steps: .

[0047] Process and post-processing: The preparation method was basically the same as that of Synthesis Example 1. The reaction yielded compound 45 (yield 24.2%). ESI-MS (m / z) (M+): theoretical value 1039.27, measured value 1039.31. Elemental analysis results (molecular formula C...) 70 H 45 O2N3Se).

[0048] Synthesis example 5: Compound 54 .

[0049] Synthesis steps: .

[0050] Process and post-processing: The preparation method was basically the same as that in Synthesis Example 1. The reaction yielded compound 54 (yield 23.4%). ESI-MS (m / z) (M+): theoretical value 991.27, measured value 991.22. Elemental analysis results (molecular formula C...) 66 H 45 O2N3Se).

[0051] Synthesis example 6: Compound 67 .

[0052] Synthesis steps: .

[0053] Process and post-processing: The preparation method was basically the same as that of Synthesis Example 1. The reaction yielded compound 67 (yield 25.8%). ESI-MS (m / z) (M+): theoretical value 925.29, measured value 925.21. Elemental analysis results (molecular formula C...) 60 H 27 D 12 O2N3Se).

[0054] Synthesis example 7: Compound 77 .

[0055] Synthesis steps: .

[0056] Process and post-processing: The preparation method was basically the same as in Synthesis Example 1. The reaction yielded compound 77 (yield 19.8%). ESI-MS (m / z) (M+): theoretical value 1003.34, measured value 1003.37. Elemental analysis results (molecular formula C...) 66 H 33 D 12 O2N3Se).

[0057] Synthesis example 8: Compound 85 .

[0058] Synthesis steps: .

[0059] Process and post-processing: The preparation method was basically the same as that of Synthesis Example 1. The reaction yielded compound 85 (yield 24.5%). ESI-MS (m / z) (M+): theoretical value 937.44, measured value 937.41. Elemental analysis results (molecular formula C...) 66 H 45 D6O2N4).

[0060] Synthesis example 9: Compound 100 .

[0061] Synthesis steps: .

[0062] Process and post-processing: The preparation method was basically the same as that of Synthesis Example 1. The reaction yielded compound 100 (yield 22.2%). ESI-MS (m / z) (M+): theoretical value 793.26, measured value 793.18. Elemental analysis results (molecular formula C...) 56 H 33 O2N4).

[0063] Synthesis example 10: Compound 119 .

[0064] Synthesis steps: .

[0065] Process and post-processing: The preparation method was basically the same as that in Synthesis Example 1. The reaction yielded compound 119 (yield 24.7%). ESI-MS (m / z) (M+): theoretical value 851.31, measured value 851.27. Elemental analysis results (molecular formula C...) 60 H 41 O3N3).

[0066] Synthesis example 11: Compound 141 .

[0067] Synthesis steps: .

[0068] Process and post-processing: The preparation method was basically the same as that in Synthesis Example 1. The reaction yielded compound 141 (yield 21.1%). ESI-MS (m / z) (M+): theoretical value 827.30, measured value 827.33. Elemental analysis results (molecular formula C...) 58 H 29 D6O3N3).

[0069] Synthesis example 12: Compound 159 .

[0070] Synthesis steps: .

[0071] Process and post-processing: The preparation method was basically the same as that of Synthesis Example 1. The reaction yielded compound 159 (yield 20.4%). ESI-MS (m / z) (M+): theoretical value 738.28, measured value 738.23. Elemental analysis results (molecular formula C...) 52 H 26 D6O3N2).

[0072] Synthesis example 13: Compound 170 .

[0073] Synthesis steps: .

[0074] Process and post-processing: The preparation method was basically the same as that of Synthesis Example 1. The reaction yielded compound 170 (yield 23.7%). ESI-MS (m / z) (M+): theoretical value 1017.49, measured value 1017.53. Elemental analysis results (molecular formula C...) 72 H 63 O3N3).

[0075] Synthesis example 14: Compound 189 .

[0076] Synthesis steps: .

[0077] Process and post-processing: The preparation method was basically the same as that of Synthesis Example 1. The reaction yielded compound 189 (yield 26.3%). ESI-MS (m / z) (M+): theoretical value 941.45, measured value 941.42. Elemental analysis results (molecular formula C...) 66 H 47 D6O3N3).

[0078] Synthesis example 15: Compound 200 .

[0079] Synthesis steps: .

[0080] Process and post-processing: The preparation method was basically the same as in Synthesis Example 1. The reaction yielded compound 200 (yield 25.3%). ESI-MS (m / z) (M+): theoretical value 839.26, measured value 839.31. Elemental analysis results (molecular formula C...) 58 H 37 O2N3S).

[0081] Synthesis example 16: Compound 225 .

[0082] Synthesis steps: .

[0083] Synthesis example 17: Compound 236 .

[0084] Synthesis steps: .

[0085] Process and post-processing: The preparation method was basically the same as that of Synthesis Example 1. The reaction yielded compound 236 (yield 18.8%). ESI-MS (m / z) (M+): theoretical value 871.32, measured value 871.31. Elemental analysis results (molecular formula C...) 60 H 33 D6O2N3S).

[0086] Synthesis example 18: Compound 246 .

[0087] Synthesis steps: .

[0088] Process and post-processing: The preparation method was basically the same as that of Synthesis Example 1. The reaction yielded compound 246 (yield 17.9%). ESI-MS (m / z) (M+): theoretical value 754.26, measured value 754.24. Elemental analysis results (molecular formula C...) 52 H 26 D6O2N2S).

[0089] Synthesis example 19: Compound 260 .

[0090] Synthesis steps: .

[0091] Process and post-processing: The preparation method was basically the same as that of Synthesis Example 1. The reaction yielded compound 260 (yield 26.6%). ESI-MS (m / z) (M+): theoretical value 1055.43, measured value 1055.38. Elemental analysis results (molecular formula C...) 76 H 55 O2N4).

[0092] Material performance testing.

[0093] 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 113.52℃, and the thermogravimetric temperature (Td) of compound 1 is 437.71℃. 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.

[0094] Device performance testing.

[0095] ITO / Ag / ITO was used as the anode substrate material, and its surface was 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 the electron transport layer (ETL) 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.

[0096] .

[0097] Compounds 15, 30, 45, 54, 67, 77, 85, 100, 119, 141, 159, 170, 189, 200, 225, 236, 246, and 260, prepared in Synthesis Examples 2-19 of the present 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 2-19.

[0098] Compare with Examples 1-5 Compounds 29, 145, 273, 282, and 320 from US12207549B2 were used as the second dopant materials for the luminescent layer, and the rest were the same as in Application Example 1, thereby preparing Comparative Examples 1-5.

[0099] .

[0100] The organic electroluminescent devices prepared in Application Examples 1-19 and Comparative Examples 1-5 were subjected to device performance tests at a current density of 10 mA / cm². 2 The test was conducted under the specified conditions, and the results are shown in Table 1 below.

[0101] Table 1

[0102] 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.

[0103] The organic electroluminescent devices prepared in Comparative Examples 1-5 and Application Examples 1-19 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:

[0104] Table 2

[0105] 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.

[0106] The detailed descriptions listed above are merely specific illustrations 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. Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This descriptive method is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can 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, X is selected from O, N, S, Se; rings a and b, which may be the same or different, are selected from H, D, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, and substituted or unsubstituted amino groups. At least one of rings a and b in Formula 1 is a substituted or unsubstituted nitrogen-containing heteroaryl or a substituted or unsubstituted amino group; R1-R 11 Each of the following is independently selected from H, D, F, substituted or unsubstituted C1-C10 straight-chain or branched alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C5-C30 heteroaryl; the substituent is selected from hydrogen, deuterium, fluorine, deuterated or undeuterated C1-C20 alkyl, deuterated or undeuterated C6-C20 aryl, deuterated or undeuterated C5-C20 heteroaryl.

2. The organic electroluminescent compound as described in claim 1, characterized in that, In Formula 1, rings a and b, which may be identical or different, are selected from H, D, substituted or unsubstituted phenyl, substituted or unsubstituted diarylamine, and substituted or unsubstituted carbazole; the substituents are selected from H, D, F, deuterated or undeuterated C1-C20 alkyl, deuterated or undeuterated C6-C20 aryl, deuterated or undeuterated C5-C20 heteroaryl, and at least one of rings a and b is a substituted or unsubstituted nitrogen-containing heteroaryl or a substituted or unsubstituted amine.

3. The organic electroluminescent compound as described in claim 1, characterized in that, In Formula 1, rings a and b, which may be identical or different, are selected from the following groups: ； Ra is independently selected from deuterated or undeuterated C1-C20 alkyl groups, deuterated or undeuterated C6-C20 aryl groups, x is independently selected from integers from 0 to 5, y is independently selected from integers from 0 to 4, and at least one of ring a and ring b is a substituted or unsubstituted nitrogen-containing heteroaryl group or a substituted or unsubstituted amino group.

4. The organic electroluminescent compound as described in claim 1, characterized in that, In Formula 1, rings a and b, which may be identical or different, are selected from the following groups: ， Where * represents a linking site, and at least one of ring a and ring b is a substituted or unsubstituted nitrogen-containing heteroaryl group or a substituted or unsubstituted amino group.

5. An organic electroluminescent compound as described in claim 1, characterized in that, Organic electroluminescent compounds are shown in Formula 2-4: ， Where R1-R 13 Each of the following is independently selected from H, D, F, substituted or unsubstituted C1-C10 straight-chain or branched alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C5-C30 heteroaryl; the substituent is selected from hydrogen, deuterium, fluorine, deuterated or undeuterated C1-C20 alkyl, deuterated or undeuterated C6-C20 aryl, deuterated or undeuterated C5-C20 heteroaryl; L1 and L2 are each independently selected from substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C5-C30 heteroaryl; a and b are each independently selected from 0 or 1; Ar1, Ar2, Ar3, and Ar4 are each independently selected from substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C5-C30 heteroaryl, Ar1 and Ar2 can be linked to form a ring, and Ar3 and Ar4 can be linked to form a ring.

6. The organic electroluminescent compound as described in claim 1, characterized in that, The organic electroluminescent compound is one of the following structural formulas: 。 7. 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 1-6.

8. An organic electroluminescent device according to claim 7, 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 1-6.

9. An organic electroluminescent device according to claim 8, characterized in that, The light-emitting layer contains an organic electroluminescent compound as described in any one of claims 1-6.

10. An electronic display device, characterized in that, It contains the organic electroluminescent device as described in claim 7.

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