Organic electroluminescent compound and electroluminescent material and electroluminescent device thereof

Abstract

The invention relates to the technical field of electroluminescent materials, and particularly discloses an organic electroluminescent compound, an electroluminescent material thereof and an electroluminescent device. When the organic electroluminescent compound is used as an electron transport material to be applied to an electroluminescent device, the driving voltage is remarkably reduced through ordered arrangement of molecules, the current efficiency is improved through optimized energy level matching, and the service life of the device is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of electroluminescent materials, and in particular to an organic electroluminescent compound and an electroluminescent material and an electroluminescent device thereof. Background Art

[0002] Organic electroluminescence materials have broad application prospects in the fields of display and lighting. Organic light-emitting diodes (OLEDs) have been widely used in high-end display devices such as smartphones and televisions due to their advantages such as self-luminescence, fast response speed, high contrast, and flexible processing. Electroluminescent devices are mainly composed of cathodes, anodes, and multiple organic functional layers in between. Among them, the electron transport layer is a key component that directly affects the efficiency and life of the device.

[0003] Traditional organic electroluminescent materials have many performance bottlenecks. On the one hand, due to weak intermolecular interactions, some materials are difficult to form an ordered arrangement under the action of an electric field, resulting in low carrier transfer efficiency, which in turn increases the device driving voltage. For example, some polymer electron transport materials are prone to leakage under high voltage, affecting device stability. On the other hand, the energy level matching of existing materials needs to be optimized. If the energy level difference between the electron transport layer and the light-emitting layer is too large, electron injection will be difficult, which will reduce the luminescence efficiency; if the energy level difference is too small, it may cause problems such as exciton quenching.

[0004] The current research and development of organic electroluminescent materials mainly focuses on molecular structure design and performance optimization. Researchers try to improve material performance by introducing specific groups into the molecular structure or changing the substitution position. However, existing research still has limitations. The synthesis process of some materials is complicated and costly, and the performance improvement effect is not significant. For example, although some phosphorescent materials containing heavy metal atoms can improve the luminous efficiency, they are difficult to apply on a large scale due to the toxicity and cost of heavy metals. Therefore, the development of new organic electroluminescent materials and the improvement of device performance and process feasibility are the current key research directions in this field. Summary of the invention

[0005] To achieve the above object, the technical solution adopted by the present invention is: an organic electroluminescent compound, wherein the organic electroluminescent compound is a compound represented by the following chemical formula 1: Chemical formula 1; Where L 1 is a single bond, phenylene or naphthylene; Where X 1 , X 2 , X 3 Each independently is N or CH, wherein X 1 -X 3At least one of them is N; Where R 1 , R 2 are each independently selected from hydrogen or deuterium; Among them, Ar 1 ,Ar 2 are each independently substituted or unsubstituted C 6 -C 60 aryl, or a substituted or unsubstituted C 5 -C 60 heteroaryl; Among them, Ar 3 is phenyl, biphenyl or terphenyl.

[0006] Further, the Ar 1 ,Ar 2 Each is independently selected from the group consisting of phenyl, dibenzofuranyl, dibenzothienyl and carbazolyl.

[0007] Further, the compound is selected from but not limited to the compounds represented by any one of the structures E1-E45 below: ; ; ; ; ; ; ; ; ; ; ; ; Wherein D represents deuterium.

[0008] An electroluminescent material comprises the above compound.

[0009] An electroluminescent device, comprising a cathode, an anode and a light-emitting layer located between the cathode and the anode, an electron injection layer and an electron transport layer are arranged between the cathode and the light-emitting layer, the electron injection layer is closer to the cathode than the electron transport layer, a hole transport layer and a hole injection layer are arranged between the anode and the light-emitting layer, the hole injection layer is closer to the anode than the hole transport layer, and the material of the electron transport layer is the above-mentioned electroluminescent material.

[0010] Furthermore, the material of the anode is metal, metal oxide or conductive polymer.

[0011] Furthermore, the metal is selected from any one of copper, gold, silver, iron, chromium, nickel and platinum.

[0012] Furthermore, the metal oxide is selected from any one of indium tin oxide, indium zinc oxide and zinc oxide.

[0013] Furthermore, the conductive polymer is selected from polyaniline or polypyrrole.

[0014] Furthermore, the cathode is made of metal or multi-layer metal material.

[0015] Furthermore, the multilayer metal is selected from LiF, Al, LiO 2 and Al, BaF 2 and Al.

[0016] Furthermore, the compound represented by Chemical Formula 1 is used as an electron transport layer material.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. Reduce the driving voltage: The organic electroluminescent compound of the present invention uses terminal pyridine, and the existence of intermolecular hydrogen bonds allows the molecules to form an orderly arrangement, which effectively reduces the driving voltage of the device. 2. Improve the current efficiency: By optimizing the molecular structure, especially the use of a double-substituted electron-withdrawing group at the dibenzofuran end, the present invention significantly improves the energy level matching of the material. This makes electron injection and transmission more efficient, and the exciton formation and recombination process smoother, thereby greatly improving the current efficiency. 3. Extend the device life: The compound structure design of the present invention effectively inhibits factors such as exciton quenching and molecular aggregation that lead to device performance degradation. Experimental data show that the device life (LT95@50J) is significantly extended to a maximum of 157 hours, showing excellent stability. This is of great significance for the practical application of organic electroluminescent devices, and greatly improves the reliability and service life of the device. DETAILED DESCRIPTION

[0018] The following will be combined with the content of the invention in the present invention to clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example 1 This embodiment provides an organic compound E1, the structure of which is as follows: ; The synthesis method of the organic compound E1 comprises the following steps: ; Synthesis of IM-2: IM-1 (50 g, 0.21 mol) was added to a 1000 ml three-necked flask and dissolved in 400 ml of DMF. The temperature was lowered to 0°C and a solution of NBS (N-bromosuccinimide) (39.2 g, 0.22 mol) in DMF (N,N-dimethylformamide) (200 ml) was added dropwise. After the addition was complete, the temperature was raised to 25°C and the reaction was carried out for 3 hours. The raw material IM-1 was less than 0.5% and the reaction was complete. The reaction solution was added to water and solid precipitated. The crude product was filtered to obtain a crude product. The crude product was slurried with 150 ml of ethanol, filtered and dried to obtain the intermediate IM-2 (58.5 g, yield 88%).

[0020] Synthesis of IM-3: In a 1000ml three-necked flask, add IM-2 (58.5g, 0.18mol), 3-pyridineboronic acid (22.6g, 0.18mol), dissolved in 300ml toluene, 150ml ethanol mixed solvent, add potassium carbonate (49.7g, 0.36mol), add 150ml water, replace nitrogen, add tetrakistriphenylphosphine palladium (1g, 0.9mmol), heat to 80℃ and reflux for 5 hours, take samples for detection, raw material IM-2 <0.5%, the reaction is complete, cool to 30℃, separate the liquids, wash the organic phase with 200ml water, concentrate to obtain a crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain IM-3 intermediate (50g, yield 86%).

[0021] Synthesis of IM-4: Add IM-3 (50 g, 0.16 mol) to a 1000 ml three-necked flask, dissolve in 500 ml DMF, replace nitrogen, add palladium carbon catalyst (5 g), replace hydrogen, maintain pressure at 50 psi, react at 40 ° C for 2 hours, take samples for testing, raw material IM-3 <0.5%, the reaction is complete, cool to 30 ° C, filter, concentrate to obtain a crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain IM-4 intermediate (40.3 g, yield 89%).

[0022] Synthesis of IM-5: IM-4 (40.3 g, 0.14 mol) was added to a 1000 ml three-necked flask and dissolved in 300 ml of DMF. The temperature was lowered to 10°C and a solution of NBS (26.2 g, 0.15 mol) in DMF (200 ml) was added dropwise. After the addition was complete, the temperature was raised to 25°C and the reaction was carried out for 3 hours. The raw material IM-4 was less than 0.5%, indicating that the reaction was complete. The reaction solution was added to water and solid precipitated. The crude product was filtered to obtain a slurry with 150 ml of ethanol, filtered, and dried to obtain the intermediate IM-5 (45.2 g, yield 88%).

[0023] Synthesis of IM-6: In a 1000ml three-necked flask, add IM-5 (45.2g, 0.12mol), 3-chloro-2-methoxyphenylboronic acid (23.1g, 0.12mol), dissolved in 300ml toluene, 150ml ethanol mixed solvent, add potassium carbonate (35g, 0.25mol), add 150ml water, replace nitrogen, add tetrakistriphenylphosphine palladium (0.69g, 0.6mmol), heat to 80℃ and reflux for 5 hours, take samples for detection, raw material IM-5 <0.5%, the reaction is complete, cool to 30℃, separate the liquids, wash the organic phase with 200ml water, concentrate to obtain a crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain IM-6 intermediate (40.2g, yield 76%).

[0024] Synthesis of IM-7: IM-3 (40.2 g, 0.094 mol) was added to a 1000 ml three-necked flask, dissolved in 500 ml acetonitrile, cooled to 0°C, tert-butyl nitrite (14.5 g, 0.14 mol) was added dropwise, solid precipitated, filtered to obtain a crude product, and recrystallized using toluene: petroleum ether = 1:2 to obtain the intermediate IM-7 (31.7 g, yield 85%).

[0025] Synthesis of IM-8: IM-4 (31.7 g, 0.08 mol) was added to a 500 ml three-necked flask and dissolved in 200 ml of DMF. The temperature was lowered to 0°C and a solution of NBS (15.0) g, 0.084 mol) in DMF (100 ml) was added dropwise. After the addition was complete, the temperature was raised to 25°C and the reaction was carried out for 3 hours. The raw material IM-4 was less than 0.5%, indicating that the reaction was complete. The reaction solution was added to water and solid precipitated. The crude product was filtered to obtain a crude product. The crude product was slurried with 150 ml of ethanol, filtered, and dried to obtain the intermediate IM-5 (33.84 g, yield 89%).

[0026] Synthesis of IM-9: In a 1000ml three-necked flask, add IM-8 (33.84g, 0.071mol), phenylboric acid (8.7g, 0.071mol), dissolved in 300ml toluene, 150ml ethanol mixed solvent, add potassium carbonate (35g, 0.25mol), add 150ml water, replace nitrogen, add tetrakistriphenylphosphine palladium (0.41g, 0.36mmol), heat to 80℃ and reflux for 5 hours, take samples for detection, raw material IM-8 <0.5%, the reaction is complete, cool to 30℃, separate the liquids, wash the organic phase with 200ml water, concentrate to obtain a crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain IM-9 intermediate (24.9g, yield 74%).

[0027] Synthesis of IM-10: In a 500 ml three-necked flask, add IM-9 (24.9 g, 0.053 mol) and diboric acid pinacol ester (16.2 g, 0.064 mol), dissolve in 250 ml of 1,4-dioxane, add potassium acetate (7.8 g, 0.080 mol), replace nitrogen, add tris(dibenzylideneacetone)dipalladium (0.24 g, 0.27 mmol), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (0.26 g, 0.54 mmol), heat to 80 ° C for 5 hours, take samples for detection, IM-9 <0.5%, the reaction is complete, add 150 ml of water to quench, add 200 ml of toluene for extraction, concentrate the organic phase to obtain a crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain IM-10 intermediate (23.49 g, yield 79%).

[0028] Synthesis of E1: In a 500ml three-necked flask, add IM-10 (23.49g, 0.042mol), 2-chloro-4,6-diphenyl-1,3,5-triazine (11.2g, 0.042mol), dissolve in a mixed solvent of 150ml toluene and 75ml ethanol, add potassium carbonate (11.6g, 0.084mol), add 75ml water, replace nitrogen, add tetrakistriphenylphosphine palladium (0.24g, 0.21mmol), heat to 80℃ and reflux for 5 hours, take samples for detection, raw material IM-10 <0.5%, the reaction is complete, cool to 30℃, separate the liquids, wash the organic phase with 100ml water, concentrate to obtain a crude product, and recrystallize from toluene to obtain E1 (18.7g, yield 67%).

[0029] Structural test of target product E1: mass spectrometry detection, measured MS (MS+1): 669; 1 HNMR (300 MHz, deuterated chloroform) δ9.40-9.10 (s, 1H), δ8.90-8.70 (d, 1H), δ8.50-8.20 (m, 5H), δ8.10-7.70 (m, 8H), δ7.70-7.40 (m, 11H), δ1.70-1.50 (s, 6H).

[0030] Example 2 This embodiment provides an organic compound E2, the structure of which is as follows: ; The synthesis method of the organic compound E2 comprises the following steps: ; Synthesis of E2: In a 500 ml three-necked flask, add IM-10 (30 g, 0.053 mol) prepared in Example 1, 4-chloro-2,6-diphenylpyrimidine (14.1 g, 0.053 mol), dissolved in a mixed solvent of 150 ml toluene and 75 ml ethanol, add potassium carbonate (14.6 g, 0.11 mol), add 75 ml water, replace nitrogen, add tetrakistriphenylphosphine palladium (0.31 g, 0.27 mmol), heat to 80 ° C and reflux for 5 hours, take samples for detection, raw material IM-10 <0.5%, the reaction is complete, cool to 30 ° C, separate the liquids, wash the organic phase with 100 ml water, concentrate to obtain a crude product, and recrystallize from toluene to obtain E2 (23.1 g, yield 65%).

[0031] Structural test of target product E2: mass spectrometry detection, measured MS (MS+1): 668; 1 HNMR (300MHz, deuterated chloroform) δ9.40-9.10 (s, 1H), δ8.90-8.70 (d, 1H), δ8.50-8.20 (m, 4H), δ8.15-8.10 (s, 1H), δ8.10-7.70 (m, 9H), δ7.70-7.40 (m, 11H), δ1.70-1.50 (s, 6H).

[0032] Example 3 This embodiment provides an organic compound E4, the structure of which is as follows: ; The synthesis method of the organic compound E4 comprises the following steps: ; Synthesis of E4: In a 500 ml three-necked flask, IM-10 (30 g, 0.053 mol) prepared in Example 1 and 2-(4-bromophenyl)-4,6-diphenyl-1,3,5-triazine (10.6 g, 0.053 mol) were added, dissolved in a mixed solvent of 150 ml toluene and 75 ml ethanol, potassium carbonate (14.6 g, 0.11 mol) was added, 75 ml water was added, nitrogen was replaced, tetrakistriphenylphosphine palladium (0.31 g, 0.27 mmol) was added, and the mixture was heated to 80° C. and refluxed for 5 hours. Sampling was performed for detection. The raw material IM-10 was less than 0.5%, and the reaction was complete. The mixture was cooled to 30° C., separated, and the organic phase was washed with 100 ml water and concentrated to obtain a crude product, which was recrystallized from toluene to obtain E4 (25.38 g, yield 64%).

[0033] Structural test of target product E6: mass spectrometry detection, measured MS (MS+1): 745; 1HNMR (300 MHz, deuterated chloroform) δ9.40-9.10 (s, 1H), δ8.90-8.70 (d, 1H), δ8.50-8.20 (m, 6H), δ8.10-7.70 (m, 8H), δ7.70-7.40 (m, 14H), δ1.70-1.50 (s, 6H).

[0034] Example 4 This embodiment provides an organic compound E12, the structure of which is as follows: ; The synthesis method of the organic compound E12 comprises the following steps:

[0035] Synthesis of E12: In a 500 ml three-necked flask, IM-10 (30 g, 0.053 mol) prepared in Example 1 and 9-(4-chloro-6-phenyl-1,3,5-triazine-2-yl)-9H-carbazole (18.9 g, 0.053 mol) were added, dissolved in a mixed solvent of 150 ml toluene and 75 ml ethanol, potassium carbonate (14.6 g, 0.11 mol) was added, 75 ml water was added, nitrogen was replaced, tetrakistriphenylphosphine palladium (0.31 g, 0.27 mmol) was added, and the mixture was heated to 80 ° C and refluxed for 5 hours. Sampling and detection showed that the raw material IM-10 was <0.5%, and the reaction was complete. The temperature was lowered to 30 ° C, the liquid was separated, the organic phase was washed with 100 ml water, concentrated to obtain a crude product, and recrystallized from toluene to obtain E12 (25 g, yield 62%).

[0036] Structural test of target product E6: mass spectrometry detection, measured MS (MS+1): 758; 1 HNMR (300 MHz, deuterated chloroform) δ9.40-9.10 (s, 1H), δ8.90-8.70 (d, 1H), δ8.50-8.20 (m, 6H), δ8.10-7.70 (m, 8H), δ7.70-7.40 (m, 13H), δ1.70-1.50 (s, 6H).

[0037] Example 5 This embodiment provides an organic compound E15, the structure of which is as follows: ; The synthesis method of the organic compound E15 comprises the following steps: ; Synthesis of E15: In a 500 ml three-necked flask, add E1 (30 g, 0.045 mol) prepared in Example 1 and heavy water (3.6 g, 0.18 mol), dissolve in 300 ml of dioxane solvent, replace nitrogen, heat to 90-100 ° C and reflux for 5 hours. After the reaction is complete, cool to 30 ° C, separate the liquids, wash the organic phase with 100 ml of saturated sodium bicarbonate solution, concentrate to obtain a crude product, and recrystallize from toluene to obtain E15 (25.58 g, yield 85%).

[0038] Structural test of target product E15: mass spectrometry detection, measured MS (MS+1): 671; 1 HNMR (300 MHz, deuterated chloroform) δ9.40-9.10 (s, 1H), δ8.90-8.70 (d, 1H), δ8.50-8.20 (m, 6H), δ8.10-7.70 (m, 3H), δ7.70-7.40 (m, 13H), δ1.70-1.50 (s, 6H).

[0039] Example 6 This embodiment provides an organic compound E16, the structure of which is as follows: ; The synthesis method of the organic compound E16 comprises the following steps: ; Synthesis of IM-11: In a 1000 ml three-necked flask, add IM-8 (30 g, 0.063 mol) prepared in Example 1, 3-biphenylboric acid (12.5 g, 0.063 mol), dissolved in 300 ml toluene, 150 ml ethanol mixed solvent, add potassium carbonate (17.4 g, 0.13 mol), add 150 ml water, replace nitrogen, add tetrakistriphenylphosphine palladium (0.36 g, 0.32 mmol), heat to 80 ° C and reflux for 5 hours, take samples for detection, raw material IM-8 <0.5%, the reaction is complete, cool to 30 ° C, separate the liquids, wash the organic phase with 200 ml water, concentrate to obtain a crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain IM-11 intermediate (26.3 g, yield 76%).

[0040] Synthesis of IM-12: In a 500 ml three-necked flask, add IM-9 (24.9 g, 0.048 mol), diboric acid pinacol ester (14.6 g, 0.058 mol), dissolve in 250 ml of 1,4-dioxane, add potassium acetate (9.4 g, 0.096 mol), replace nitrogen, add tris(dibenzylideneacetone)dipalladium (0.22 g, 0.24 mmol), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (0.23 g, 0.48 mmol), heat to 80 ° C for 5 hours, take samples for detection, IM-11 <0.5%, the reaction is complete, add 150 ml of water to quench, add 200 ml of toluene for extraction, concentrate the organic phase to obtain a crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain IM-12 intermediate (22.7 g, yield 74%) Synthesis of E16: In a 500 ml three-necked flask, add IM-12 (22.7 g, 0.035 mol), 2-chloro-4,6-diphenyl-1,3,5-triazine (9.4 g, 0.035 mol), dissolve in a mixed solvent of 150 ml toluene and 75 ml ethanol, add potassium carbonate (9.8 g, 0.071 mol), add 75 ml water, replace nitrogen, add tetrakistriphenylphosphine palladium (0.2 g, 0.18 mmol), heat to 80 ° C and reflux for 5 hours, take samples for detection, raw material IM-12 <0.5%, the reaction is complete, cool to 30 ° C, separate the liquids, wash the organic phase with 100 ml water, concentrate to obtain a crude product, and recrystallize from toluene to obtain E16 (15.1 g, yield 57%).

[0041] Structural test of target product E16: mass spectrometry detection, measured MS (MS+1): 745; 1 HNMR (300 MHz, deuterated chloroform) δ9.40-9.10 (s, 1H), δ8.90-8.70 (d, 1H), δ8.50-8.20 (m, 5H), δ8.10-7.70 (m, 10H), δ7.70-7.40 (m, 13H), δ1.70-1.50 (s, 6H).

[0042] Example 7 This embodiment provides an organic compound E17, the structure of which is as follows: ; The synthesis method of the organic compound E17 comprises the following steps: ; Synthesis of E17: In a 500 ml three-necked flask, add IM-12 (30 g, 0.047 mol) prepared in Example 6, 4-chloro-2,6-diphenylpyrimidine (12.5 g, 0.047 mol), dissolved in a mixed solvent of 150 ml toluene and 75 ml ethanol, add potassium carbonate (13.0 g, 0.094 mol), add 75 ml water, replace nitrogen, add tetrakistriphenylphosphine palladium (0.27 g, 0.24 mmol), heat to 80 ° C and reflux for 5 hours, take samples for detection, raw material IM-12 <0.5%, the reaction is complete, cool to 30 ° C, separate the liquids, wash the organic phase with 100 ml water, concentrate to obtain a crude product, and recrystallize from toluene to obtain E17 (27.3 g, yield 68%).

[0043] Structural test of target product E17: mass spectrometry detection, measured MS (MS+1): 744; 1 HNMR (300MHz, deuterated chloroform) δ9.40-9.10 (s, 1H), δ8.90-8.70 (d, 1H), δ8.50-8.20 (m, 4H), δ 8.20-8.10 (s, 1H), δ8.10-7.70 (m, 11H), δ7.70-7.40 (m, 13H), δ1.70-1.50 (s, 6H).

[0044] Example 8 This embodiment provides an organic compound E27, the structure of which is as follows: ; The synthesis method of the organic compound E27 comprises the following steps: ; Synthesis of E27: In a 500 ml three-necked flask, IM-12 (30 g, 0.047 mol) prepared in Example 6 and 9-(4-chloro-6-phenyl-1,3,5-triazine-2-yl)-9H-carbazole (16.8 g, 0.047 mol) were added, dissolved in a mixed solvent of 150 ml toluene and 75 ml ethanol, potassium carbonate (13.0 g, 0.094 mol) was added, 75 ml water was added, nitrogen was replaced, tetrakistriphenylphosphine palladium (0.27 g, 0.24 mmol) was added, and the mixture was heated to 80 ° C and refluxed for 5 hours. Sampling and detection showed that the raw material IM-12 was <0.5%, and the reaction was complete. The temperature was lowered to 30 ° C, the liquid was separated, the organic phase was washed with 100 ml water, concentrated to obtain a crude product, and recrystallized from toluene to obtain E27 (21.5 g, yield 55%).

[0045] Structural test of target product E6: mass spectrometry detection, measured MS (MS+1): 834; 1HNMR (300 MHz, deuterated chloroform) δ9.40-9.10 (s, 1H), δ8.90-8.70 (d, 1H), δ8.50-8.20 (m, 6H), δ8.10-7.70 (m, 10H), δ7.70-7.40 (m, 15H), δ1.70-1.50 (s, 6H).

[0046] Performance Testing: Device 1: The organic electroluminescent element was manufactured using a Sunic sp1710 evaporator, and the specific steps were as follows: a glass substrate (anode) (Corning glass 40 mm×40 mm×0.7 mm) coated with ITO (indium tin oxide) with a thickness of 135 nm was ultrasonically cleaned with isopropyl alcohol and pure water for 5 minutes, and then cleaned with ultraviolet ozone, and then the glass substrate was transferred to a vacuum deposition chamber; The hole transport material HT1 doped with 4% PD was vacuum-deposited (about 10-7 Torr) on the transparent ITO (tin-doped indium oxide) electrode with a thickness of 20nm to form a hole injection layer. Then, a 120nm thick compound HT1 was vacuum-deposited on the hole injection layer as a hole transport layer; Then, 25 nm of BH doped with 4% BD4 by mass fraction was vacuum deposited as the light-emitting layer; then, a mixture of compound A1 and Liq (mass ratio of 50%:50%) was vacuum deposited to form an electron transport layer with a thickness of 30 nm; Finally, a 2 nm thick layer of metal ytterbium (Yb, electron injection layer) and a magnesium-silver alloy doped in a ratio of 10:1 were sequentially deposited to form a cathode; Finally, the device is transferred from the deposition chamber to a glove box, and then packaged with a UV-curable epoxy resin and a glass cover plate containing a moisture absorbent to obtain an organic electroluminescent element.

[0047] In the above manufacturing steps, the deposition rates of organic materials, metal ytterbium and metal Mg were maintained at 0.1 nm / s, 0.05 nm / s and 0.2 nm / s respectively. The structure of the organic electroluminescent element is represented as: ITO (135 nm) / HT1: 4% HD (20 nm) / HT1 (120 nm) / BH: 4% BD4 (25 nm) / A1: Liq (50%: 50%, 30 nm) / Yb (2 nm) / Mg: Ag (10: 1, 150 nm).

[0048] The structural formulas of the above-mentioned PD, HT1, BH, BD4, A1 and Liq are as follows: .

[0049] Device 2-Device 9: Referring to the preparation method of device 1, A1 therein was replaced with the compounds synthesized in Example 1 to Example 8 in sequence, and the rest remained unchanged.

[0050] The driving voltage (V) and current density (mA / cm 3 The performance data of ), current efficiency (cd / A), and life LT95@50J (hours) are shown in the table below.

[0051]

[0052] Compared with the electron transport layer material A1, the organic electroluminescent compound of the present invention uses terminal pyridine, and due to the presence of intermolecular hydrogen bonds, the molecular processes can be arranged in an orderly manner, thereby greatly reducing the driving voltage. The dibenzofuran end uses a double-substituted electron-withdrawing group, which can improve the energy level matching, improve the efficiency, and extend the device life. Therefore, an organic electroluminescent device is provided, which has high luminous efficiency and long working life while maintaining a relatively low driving voltage, thereby improving power efficiency and power consumption, and extending the device life.

[0053] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An organic electroluminescent compound, characterized in that: The organic electroluminescent compound is a compound represented by the following chemical formula 1: Chemical formula 1; Wherein L1 is a single bond, phenylene or naphthylene; wherein X1, X2, and X3 are each independently N or CH, wherein at least one of X1-X3 is N; Wherein R1, R2 are each independently selected from hydrogen or deuterium; wherein Ar1 and Ar2 are each independently substituted or unsubstituted C6-C 60 aryl, or a substituted or unsubstituted C5-C 60 heteroaryl; Wherein Ar3 is phenyl, biphenyl or terphenyl.

2. An organic electroluminescent compound according to claim 1, characterized in that: The Ar1 and Ar2 are independently selected from the group consisting of phenyl, dibenzofuranyl, dibenzothienyl and carbazolyl.

3. An organic electroluminescent compound according to claim 1, characterized in that: The compound is selected from but not limited to the compounds represented by any one of the structures E1-E45 below: ； ； ； ； ； ； ； ； ； ； ； ; Wherein D represents deuterium.

4. An electroluminescent material, characterized in that The electroluminescent material comprises the compound according to any one of claims 1 to 3.

5. An electroluminescent device, characterized in that: The electroluminescent device comprises a cathode, an anode and a light-emitting layer located between the cathode and the anode, an electron injection layer and an electron transport layer are arranged between the cathode and the light-emitting layer, the electron injection layer is closer to the cathode than the electron transport layer, a hole transport layer and a hole injection layer are arranged between the anode and the light-emitting layer, the hole injection layer is closer to the anode than the hole transport layer, and the material of the electron transport layer comprises the electroluminescent material according to claim 4.

6. The electroluminescent device according to claim 5, characterized in that The material of the anode is metal, metal oxide or conductive polymer.

7. The electroluminescent device according to claim 6, characterized in that The metal is selected from any one of copper, gold, silver, iron, chromium, nickel and platinum.

8. The electroluminescent device according to claim 6, characterized in that The metal oxide is selected from any one of indium tin oxide, indium zinc oxide and zinc oxide.

9. The electroluminescent device according to claim 6, characterized in that: The conductive polymer is selected from polyaniline or polypyrrole.

10. The electroluminescent device according to claim 5, characterized in that The cathode material is metal or multi-layer metal material; The multilayer metal is selected from any one of LiF and Al, LiO2 and Al, and BaF2 and Al.

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