An organic electroluminescent compound, an electroluminescent material and an electroluminescent device thereof

Abstract

The present invention relates to the technical field of electroluminescent materials, and specifically discloses an organic electroluminescent compound, an electroluminescent material and an electroluminescent device thereof. When the organic electroluminescent compound is used as an electron transport material in an electroluminescent device, the driving voltage is significantly reduced through the ordered arrangement of molecules, the current efficiency is improved by the optimized energy level matching, and the device life is extended.

Description

Technical Field

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

[0002] Organic electroluminescent 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 TVs due to their advantages of self-luminescence, fast response speed, high contrast, and flexible processing. An electroluminescent device mainly consists of a cathode, an anode, and multiple organic functional layers therebetween. Among them, the electron transport layer is a key component, directly affecting the device efficiency and lifespan.

[0003] Traditional organic electroluminescent materials have many performance bottlenecks. On the one hand, due to the weak intermolecular interaction of some materials, it is difficult to form an ordered arrangement under the action of an electric field, resulting in low carrier transport efficiency and thus an increase in the device driving voltage. For example, some polymer-based electron transport materials are prone to leakage at high voltages, affecting the 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 is difficult, which will reduce the light-emitting efficiency; if the energy level difference is too small, problems such as exciton quenching may occur.

[0004] The current research and development of organic electroluminescent materials mainly focus on molecular structure design and performance optimization. Researchers try to improve the material performance by introducing specific groups into the molecular structure or changing the substitution position. However, the existing research still has limitations. The synthesis processes of some materials are complex, costly, and the performance improvement effect is not significant. For example, although some phosphorescent materials containing heavy metal atoms can improve the light-emitting efficiency, due to the toxicity and cost of heavy metals, it is difficult to be applied on a large scale. Therefore, developing new organic electroluminescent materials and simultaneously improving the device performance and process feasibility are the 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, and the organic electroluminescent compound is a compound represented by the following Chemical Formula 1:

[0006] Chemical Formula 1;

[0007] wherein L1 is a single bond, a phenylene group or a naphthylene group;

[0008] wherein X1, X2, and X3 are each independently N or CH, and at least one of X1 - X3 is N;

[0009] Wherein R1 and R2 are each independently selected from hydrogen or deuterium;

[0010] Wherein Ar1 and Ar2 are each independently a substituted or unsubstituted C6-C 60 aryl, or a substituted or unsubstituted C5-C containing at least one heteroatom selected from N, O, and S 60 heteroaryl;

[0011] Wherein Ar3 is phenyl, biphenyl or terphenyl.

[0012] Furthermore, Ar1 and Ar2 are each independently selected from: phenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl.

[0013] Furthermore, the compound is selected from, but not limited to, any one of the compounds shown by the following structures E1-E45:

[0014] ;

[0015] ;

[0016] ;

[0017] ;

[0018] ;

[0019] ;

[0020] ;

[0021] ;

[0022] ;

[0023] ;

[0024] ;

[0025] ; wherein D represents deuterium.

[0026] An electroluminescent material, wherein the electroluminescent material contains the above-mentioned compound.

[0027] An electroluminescent device, which includes 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 provided between the cathode and the light-emitting layer, and the electron injection layer is closer to the cathode than the electron transport layer. A hole transport layer and a hole injection layer are provided between the anode and the light-emitting layer, and the hole injection layer is closer to the anode than the hole transport layer. The material of the electron transport layer is the above-mentioned electroluminescent material.

[0028] Further, the material of the anode is a metal, a metal oxide, or a conductive polymer.

[0029] Further, the metal is selected from any one of copper, gold, silver, iron, chromium, nickel, and platinum.

[0030] Further, the metal oxide is selected from any one of indium tin oxide, indium zinc oxide, and zinc oxide.

[0031] Further, the conductive polymer is selected from polyaniline or polypyrrole.

[0032] Further, the material of the cathode is a metal or a multi-layer metal material.

[0033] Further, the multi-layer metal is selected from any one of LiF and Al, LiO2 and Al, and BaF2 and Al.

[0034] Further, the compound shown in Chemical Formula 1 is used as the electron transport layer material.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] 1. Reducing the driving voltage: In the organic electroluminescent compound of the present invention, by using terminal pyridine, the presence of intermolecular hydrogen bonds enables the molecules to form an ordered arrangement, effectively reducing the driving voltage of the device. 2. Improving the current efficiency: By optimizing the molecular structure, especially by using double-substituted electron-withdrawing groups at the dibenzofuran end, the present invention significantly improves the energy level matching degree of the material. This makes the electron injection and transport more efficient, and the exciton formation and recombination process smoother, thus greatly improving the current efficiency. 3. Extending the device life: The compound structure design of the present invention effectively suppresses factors such as exciton quenching and molecular aggregation that cause the decline of device performance. Experimental data shows that the device life (LT95@50J) is significantly extended to a maximum of 157 hours, demonstrating excellent stability. This is of great significance for the practical application of organic electroluminescent devices, greatly improving the reliability and service life of the devices. Specific embodiments

[0037] Next, in combination with the invention content of the present invention, the technical solution of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention.

[0038] Example 1

[0039] This example provides an organic compound E1 with the following structure:

[0040] ;

[0041] The synthesis method of the organic compound E1 includes the following steps:

[0042] ;

[0043] Synthesis of IM-2: In a 1000 ml three-necked flask, add IM-1 (50 g, 0.21 mol), dissolve it in 400 ml of DMF, cool down to 0 °C, and dropwise add a solution of NBS (N-bromosuccinimide) (39.2 g, 0.22 mol) in DMF (N,N-dimethylformamide) (200 ml). After the addition is complete, raise the temperature to 25 °C and react for 3 hours. Take a sample for detection. The raw material IM-1 < 0.5%, and the reaction is complete. Add the reaction solution to water, and a solid precipitates. Filter to obtain the crude product. Pulp with 150 ml of ethanol, filter, and dry to obtain the intermediate IM-2 (58.5 g, yield 88%).

[0044] Synthesis of IM-3: In a 1000 ml three-necked flask, add IM-2 (58.5 g, 0.18 mol), 3-pyridineboronic acid (22.6 g, 0.18 mol), dissolve it in a mixed solvent of 300 ml of toluene and 150 ml of ethanol, add potassium carbonate (49.7 g, 0.36 mol), add 150 ml of water, displace nitrogen, add tetrakis(triphenylphosphine)palladium (1 g, 0.9 mmol), heat to 80 °C and reflux for 5 hours. Take a sample for detection. The raw material IM-2 < 0.5%, and the reaction is complete. Cool down to 30 °C, separate the liquid, wash the organic phase with 200 ml of water, concentrate to obtain the crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain the IM-3 intermediate (50 g, yield 86%).

[0045] Synthesis of IM-4: In a 1000 ml three-necked flask, add IM-3 (50 g, 0.16 mol), dissolve it in 500 ml of DMF, displace nitrogen, add palladium-carbon catalyst (5 g), displace hydrogen, maintain the pressure at 50 psi, and react at 40 °C for 2 hours. Take a sample for detection. The raw material IM-3 < 0.5%, the reaction is complete. Cool down to 30 °C, filter, concentrate to obtain the crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain the IM-4 intermediate (40.3 g, yield 89%).

[0046] Synthesis of IM-5: In a 1000 ml three-necked flask, add IM-4 (40.3 g, 0.14 mol), dissolve it in 300 ml of DMF, cool down to 10 °C, and dropwise add a solution of NBS (26.2 g, 0.15 mol) in DMF (200 ml). After the addition is complete, warm up to 25 °C and react for 3 hours. Take a sample for detection. The raw material IM-4 < 0.5%, the reaction is complete. Add the reaction solution to water, and a solid precipitates. Filter to obtain the crude product, slurry it with 150 ml of ethanol, filter, and dry to obtain the intermediate IM-5 (45.2 g, yield 88%).

[0047] Synthesis of IM-6: In a 1000 ml three-necked flask, add IM-5 (45.2 g, 0.12 mol) and 3-chloro-2-methoxyphenylboronic acid (23.1 g, 0.12 mol), dissolve them in a mixed solvent of 300 ml of toluene and 150 ml of ethanol, add potassium carbonate (35 g, 0.25 mol), add 150 ml of water, displace nitrogen, add tetrakis(triphenylphosphine)palladium (0.69 g, 0.6 mmol), heat to 80 °C and reflux for 5 hours. Take a sample for detection. The raw material IM-5 < 0.5%, the reaction is complete. Cool down to 30 °C, separate the layers, wash the organic phase with 200 ml of water, concentrate to obtain the crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain the IM-6 intermediate (40.2 g, yield 76%).

[0048] Synthesis of IM-7: In a 1000 ml three-necked flask, add IM-3 (40.2 g, 0.094 mol), dissolve it in 500 ml of acetonitrile, cool down to 0 °C, and dropwise add tert-butyl nitrite (14.5 g, 0.14 mol). A solid precipitates. Filter to obtain the crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain the intermediate IM-7 (31.7 g, yield 85%).

[0049] Synthesis of IM-8: In a 500 ml three-necked flask, add IM-4 (31.7 g, 0.08 mol), dissolve it in 200 ml of DMF, cool down to 0 °C, and dropwise add a solution of NBS (15.0 g, 0.084 mol) in DMF (100 ml). After the addition is complete, warm up to 25 °C and react for 3 hours. Take a sample for detection. The raw material IM-4 < 0.5%, and the reaction is complete. Add the reaction solution to water, and a solid precipitates. Filter to obtain the crude product. Pulp it with 150 ml of ethanol, filter, and dry to obtain the intermediate IM-5 (33.84 g, yield 89%).

[0050] Synthesis of IM-9: In a 1000 ml three-necked flask, add IM-8 (33.84 g, 0.071 mol) and phenylboronic acid (8.7 g, 0.071 mol), dissolve them in a mixed solvent of 300 ml of toluene and 150 ml of ethanol. Add potassium carbonate (35 g, 0.25 mol), add 150 ml of water, displace nitrogen, add tetrakis(triphenylphosphine)palladium (0.41 g, 0.36 mmol), heat to 80 °C and reflux for 5 hours. Take a sample for detection. The raw material IM-8 < 0.5%, and the reaction is complete. Cool down to 30 °C, separate the liquid, wash the organic phase with 200 ml of water, concentrate to obtain the crude product, and recrystallize with toluene:petroleum ether = 1:2 to obtain the intermediate IM-9 (24.9 g, yield 74%).

[0051] Synthesis of IM-10: In a 500 ml three-necked flask, add IM-9 (24.9 g, 0.053 mol) and bis(pinacolato)diboron (16.2 g, 0.064 mol), dissolve them in 250 ml of 1,4-dioxane. Add potassium acetate (7.8 g, 0.080 mol), displace nitrogen, add tris(dibenzylideneacetone)dipalladium (0.24 g, 0.27 mmol) and 2-(dicyclohexylphosphino)-2',4',6'-triisopropylbiphenyl (0.26 g, 0.54 mmol), heat to 80 °C and react for 5 hours. Take a sample for detection. IM-9 < 0.5%, and the reaction is complete. Add 150 ml of water to quench, add 200 ml of toluene for extraction, concentrate the organic phase to obtain the crude product, and recrystallize with toluene:petroleum ether = 1:2 to obtain the intermediate IM-10 (23.49 g, yield 79%).

[0052] Synthesis of E1: In a 500 ml three-necked flask, add IM-10 (23.49 g, 0.042 mol), 2-chloro-4,6-diphenyl-1,3,5-triazine (11.2 g, 0.042 mol), dissolve in a mixed solvent of 150 ml of toluene and 75 ml of ethanol, add potassium carbonate (11.6 g, 0.084 mol), add 75 ml of water, displace nitrogen, add tetrakis(triphenylphosphine)palladium (0.24 g, 0.21 mmol), heat to 80 °C and reflux for 5 hours. Take a sample for detection. The raw material IM-10 < 0.5%, the reaction is complete. Cool to 30 °C, separate the liquid, wash the organic phase with 100 ml of water, concentrate to obtain a crude product, and recrystallize with toluene to obtain E1 (18.7 g, yield 67%).

[0053] Structure test of the target product E1: Mass spectrometry detection, MS(MS + 1) measured: 669; 1 HNMR(300 MHz, chloroform-d) 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).

[0054] Example 2

[0055] This example provides an organic compound E2 with the following structure:

[0056] ;

[0057] The synthesis method of this organic compound E2 includes the following steps:

[0058] ;

[0059] 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), dissolve in a mixed solvent of 150 ml of toluene and 75 ml of ethanol, add potassium carbonate (14.6 g, 0.11 mol), add 75 ml of water, displace nitrogen, add tetrakis(triphenylphosphine)palladium (0.31 g, 0.27 mmol), heat to 80 °C and reflux for 5 hours. Take a sample for detection. The raw material IM-10 < 0.5%, the reaction is complete. Cool to 30 °C, separate the liquid, wash the organic phase with 100 ml of water, concentrate to obtain a crude product, and recrystallize with toluene to obtain E2 (23.1 g, yield 65%).

[0060] Structure test of the target product E2: Mass spectrometry detection, MS(MS + 1) measured: 668; 1HNMR (300 MHz, chloroform-d) δ 9.40 - 9.10 (s, 1H), δ 8.90 - 8.70 (d, 1H), δ 8.50 - 8.20 (m, 4H), δ 8.15 - 8.10 (s, 1H), δ 8.10 - 7.70 (m, 9H), δ 7.70 - 7.40 (m, 11H), δ 1.70 - 1.50 (s, 6H).

[0061] Example 3

[0062] This example provides an organic compound E4 with the following structure:

[0063] ;

[0064] The synthesis method of this organic compound E4 includes the following steps:

[0065] ;

[0066] Synthesis of E4: In a 500 ml three-necked flask, add IM-10 (30 g, 0.053 mol) prepared in Example 1, 2-(4-bromophenyl)-4,6-diphenyl-1,3,5-triazine (10.6 g, 0.053 mol), dissolve in a mixed solvent of 150 ml of toluene and 75 ml of ethanol, add potassium carbonate (14.6 g, 0.11 mol), add 75 ml of water, displace nitrogen, add tetrakis(triphenylphosphine)palladium (0.31 g, 0.27 mmol), heat to 80 °C and reflux for 5 hours. Take a sample for detection. The raw material IM-10 < 0.5%, the reaction is complete. Cool to 30 °C, separate the liquid, wash the organic phase with 100 ml of water, concentrate to obtain the crude product, and recrystallize with toluene to obtain E4 (25.38 g, yield 64%).

[0067] Structure test of the target product E6: Detected by mass spectrometry, MS (MS + 1): 745; 1 HNMR (300 MHz, chloroform-d) δ 9.40 - 9.10 (s, 1H), δ 8.90 - 8.70 (d, 1H), δ 8.50 - 8.20 (m, 6H), δ 8.10 - 7.70 (m, 8H), δ 7.70 - 7.40 (m, 14H), δ 1.70 - 1.50 (s, 6H).

[0068] Example 4

[0069] This example provides an organic compound E12 with the following structure:

[0070] ;

[0071] The synthesis method of this organic compound E12 includes the following steps:

[0072]

[0073] Synthesis of E12: In a 500 ml three-necked flask, add IM-10 (30 g, 0.053 mol) prepared in Example 1 and 9-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)-9H-carbazole (18.9 g, 0.053 mol). Dissolve them in a mixed solvent of 150 ml of toluene and 75 ml of ethanol. Add potassium carbonate (14.6 g, 0.11 mol), then add 75 ml of water. Replace the nitrogen, add tetrakis(triphenylphosphine)palladium (0.31 g, 0.27 mmol), and heat to 80 °C for reflux reaction for 5 hours. Take a sample for detection. When the raw material IM-10 < 0.5%, the reaction is complete. Cool down to 30 °C, separate the liquid. Wash the organic phase with 100 ml of water, concentrate to obtain the crude product, and recrystallize with toluene to obtain E12 (25 g, yield 62%).

[0074] Structure test of the target product E6: Detection by mass spectrometry, MS(MS + 1) measured: 758; 1 HNMR (300 MHz, chloroform-d) 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).

[0075] Example 5

[0076] This example provides an organic compound E15 with the following structure:

[0077] ;

[0078] The synthesis method of this organic compound E15 includes the following steps:

[0079] ;

[0080] 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 them in 300 ml of dioxane solvent. Replace the nitrogen, heat to 90 - 100 °C for reflux reaction for 5 hours. When the reaction is complete, cool down to 30 °C, separate the liquid. Wash the organic phase with 100 ml of saturated sodium hydrogen carbonate solution, concentrate to obtain the crude product, and recrystallize with toluene to obtain E15 (25.58 g, yield 85%).

[0081] Structure test of the target product E15: Detection by mass spectrometry, MS(MS + 1) measured: 671; 1HNMR (300 MHz, chloroform-d) δ 9.40 - 9.10 (s, 1H), δ 8.90 - 8.70 (d, 1H), δ 8.50 - 8.20 (m, 6H), δ 8.10 - 7.70 (m, 3H), δ 7.70 - 7.40 (m, 13H), δ 1.70 - 1.50 (s, 6H).

[0082] Example 6

[0083] This example provides an organic compound E16 with the following structure:

[0084] ;

[0085] The synthesis method of this organic compound E16 includes the following steps:

[0086] ;

[0087] Synthesis of IM-11: In a 1000 ml three-necked flask, add IM-8 (30 g, 0.063 mol) prepared in Example 1 and 3-biphenylboronic acid (12.5 g, 0.063 mol), dissolve them in a mixed solvent of 300 ml of toluene and 150 ml of ethanol, add potassium carbonate (17.4 g, 0.13 mol), add 150 ml of water, displace nitrogen, add tetrakis(triphenylphosphine)palladium (0.36 g, 0.32 mmol), heat to 80 °C and reflux for 5 hours. Take a sample for detection. The raw material IM-8 < 0.5%, the reaction is complete. Cool down to 30 °C, separate the liquid, wash the organic phase with 200 ml of water, concentrate to obtain the crude product, and recrystallize with toluene:petroleum ether = 1:2 to obtain the IM-11 intermediate (26.3 g, yield 76%).

[0088] Synthesis of IM-12: In a 500 ml three-necked flask, add IM-9 (24.9 g, 0.048 mol) and bis(pinacolato)diboron (14.6 g, 0.058 mol), dissolve them in 250 ml of 1,4-dioxane, add potassium acetate (9.4 g, 0.096 mol), displace nitrogen, add tris(dibenzylideneacetone)dipalladium (0.22 g, 0.24 mmol) and 2-(dicyclohexylphosphino)-2',4',6'-triisopropylbiphenyl (0.23 g, 0.48 mmol), heat to 80 °C and react for 5 hours. Take a sample 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 the crude product, and recrystallize with toluene:petroleum ether = 1:2 to obtain the IM-12 intermediate (22.7 g, yield 74%)

[0089] 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 them in a mixed solvent of 150 ml of toluene and 75 ml of ethanol, add potassium carbonate (9.8 g, 0.071 mol), add 75 ml of water, displace nitrogen, add tetrakis(triphenylphosphine)palladium(0) (0.2 g, 0.18 mmol), heat to 80 °C and reflux for 5 hours. Take a sample for detection. The raw material IM-12 < 0.5%, the reaction is complete. Cool down to 30 °C, separate the liquid, wash the organic phase with 100 ml of water, concentrate to obtain the crude product, and recrystallize with toluene to obtain E16 (15.1 g, yield 57%).

[0090] Structure test of the target product E16: Detection by mass spectrometry, measured MS(MS + 1): 745; 1 HNMR (300 MHz, chloroform-d) 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).

[0091] Example 7

[0092] This example provides an organic compound E17, the structure is as follows:

[0093] ;

[0094] The synthesis method of this organic compound E17 includes the following steps:

[0095] ;

[0096] Synthesis of E17: In a 500 ml three-necked flask, add the IM-12 (30 g, 0.047 mol) prepared in Example 6, 4-chloro-2,6-diphenylpyrimidine (12.5 g, 0.047 mol), dissolve them in a mixed solvent of 150 ml of toluene and 75 ml of ethanol, add potassium carbonate (13.0 g, 0.094 mol), add 75 ml of water, displace nitrogen, add tetrakis(triphenylphosphine)palladium(0) (0.27 g, 0.24 mmol), heat to 80 °C and reflux for 5 hours. Take a sample for detection. The raw material IM-12 < 0.5%, the reaction is complete. Cool down to 30 °C, separate the liquid, wash the organic phase with 100 ml of water, concentrate to obtain the crude product, and recrystallize with toluene to obtain E17 (27.3 g, yield 68%).

[0097] Structure test of the target product E17: Detection by mass spectrometry, measured MS(MS + 1): 744; 1HNMR (300 MHz, chloroform-d) δ 9.40 - 9.10 (s, 1H), δ 8.90 - 8.70 (d, 1H), δ 8.50 - 8.20 (m, 4H), δ 8.20 - 8.10 (s, 1H), δ 8.10 - 7.70 (m, 11H), δ 7.70 - 7.40 (m, 13H), δ 1.70 - 1.50 (s, 6H).

[0098] Example 8

[0099] This example provides an organic compound E27 with the following structure:

[0100] ;

[0101] The synthesis method of this organic compound E27 includes the following steps:

[0102] ;

[0103] Synthesis of E27: In a 500 ml three-necked flask, add IM-12 (30 g, 0.047 mol) prepared in Example 6, 9-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)-9H-carbazole (16.8 g, 0.047 mol), dissolve in a mixed solvent of 150 ml of toluene and 75 ml of ethanol, add potassium carbonate (13.0 g, 0.094 mol), add 75 ml of water, displace nitrogen, add tetrakis(triphenylphosphine)palladium (0.27 g, 0.24 mmol), heat to 80 °C and reflux for 5 hours. Take a sample for detection. The raw material IM-12 < 0.5%, the reaction is complete. Cool to 30 °C, separate the liquid, wash the organic phase with 100 ml of water, concentrate to obtain a crude product, and recrystallize with toluene to obtain E27 (21.5 g, yield 55%).

[0104] Structure test of the target product E6: Mass spectrometry detection, measured MS (MS + 1): 834; 1 HNMR (300 MHz, chloroform-d) δ 9.40 - 9.10 (s, 1H), δ 8.90 - 8.70 (d, 1H), δ 8.50 - 8.20 (m, 6H), δ 8.10 - 7.70 (m, 10H), δ 7.70 - 7.40 (m, 15H), δ 1.70 - 1.50 (s, 6H).

[0105] Performance test:

[0106] Device 1:

[0107] Manufacture of an organic electroluminescent device using a Sunic sp1710 evaporation coater. The specific steps are 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 is ultrasonically washed with isopropyl alcohol and pure water for 5 minutes respectively, then cleaned with ultraviolet ozone, and then the glass substrate is transferred to a vacuum deposition chamber;

[0108] The hole transport material HT1 doped with 4% PD is thermally deposited in a vacuum (about 10-7 Torr) with a thickness of 20 nm on a transparent ITO (indium tin oxide doped) electrode to form a hole injection layer. Then, a compound HT1 with a thickness of 120 nm is vacuum deposited on the hole injection layer as a hole transport layer;

[0109] Then, BH doped with 4% BD4 by mass fraction with a thickness of 25 nm is vacuum deposited as a light-emitting layer; Then, a blend of compound A1 and Liq (mass ratio 50%:50%) is vacuum deposited to form an electron transport layer with a thickness of 30 nm;

[0110] Finally, a 2-nm-thick ytterbium metal (Yb, electron injection layer) and a magnesium-silver alloy with a doping ratio of 10:1 are deposited in sequence to form a cathode;

[0111] Finally, the device is transferred from the deposition chamber to a glove box, and then encapsulated with a UV-curable epoxy resin and a glass cover plate containing a moisture absorbent to obtain an organic electroluminescent device.

[0112] In the above manufacturing steps, the deposition rates of the organic material, ytterbium metal, and magnesium metal are maintained at 0.1 nm / s, 0.05 nm / s, and 0.2 nm / s respectively. The structure of this organic electroluminescent device is expressed as: ITO(135 nm) / HT1:4%HD (20nm) / HT1(120 nm) / BH:4%BD4 (25 nm) / A1: Liq(50%:50%,30nm) / Yb (2 nm) / Mg:Ag (10:1,150 nm).

[0113] The structural formulas of the above PD, HT1, BH, BD4, A1, and Liq are as follows:

[0114] .

[0115] Devices 2 - 9: Referring to the preparation method of Device 1, the A1 in it is sequentially replaced with the compounds synthesized in Examples 1 to 8, and the rest remains unchanged.

[0116] The driving voltages (V) and current densities (mA / cm 3) The performance data of current efficiency (cd / A) and lifetime LT95@50J (hours) are shown in the following table.

[0117]

[0118] Compared with the electron transport layer material A1, the organic electroluminescent compound of the present invention can make the molecules arrange orderly due to the existence of intermolecular hydrogen bonds by using terminal pyridine, thereby greatly reducing the driving voltage. The dibenzofuran end adopts a double-substituted electron-withdrawing group, which can improve the energy level matching degree, increase the efficiency, and extend the device lifetime. Therefore, an organic electroluminescent device is provided. This device has a high luminous efficiency and a long working lifetime while maintaining a relatively low driving voltage, thereby improving the power efficiency and power consumption and increasing the device lifetime.

[0119] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. 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, a phenylene group or a naphthylene group; wherein X1, X2, and X3 are each independently N or CH, and at least one of X1 - X3 is N; wherein R1 and R2 are each independently selected from hydrogen or deuterium; wherein Ar1 and Ar2 are each independently selected from: a phenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a carbazolyl group.

2. An organic electroluminescent compound according to claim 1, characterized in that, The compound is selected from any one of the compounds represented by the following structures E1 - E45: ； ； ； ； ； ； ； ； ； ； ； ; wherein D represents deuterium.

3. An electroluminescent material, characterized in that, The electroluminescent material contains the compound described in any one of claims 1 - 2.

4. An electroluminescent device, characterized in that, The electroluminescent device includes 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 provided 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 provided 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 includes the electroluminescent material described in claim 3.

5. The electroluminescent device according to claim 4, characterized in that, The material of the anode is a metal, a metal oxide, or a conductive polymer.

6. The electroluminescent device according to claim 5, wherein The metal is selected from any one of copper, gold, silver, iron, chromium, nickel, and platinum.

7. The electroluminescent device according to claim 5, characterized in that, The metal oxide is selected from any one of indium tin oxide, indium zinc oxide, and zinc oxide.

8. The electroluminescent device according to claim 5, characterized in that, The conductive polymer is selected from polyaniline or polypyrrole.

9. The electroluminescent device according to claim 4, characterized in that, The material of the cathode is a metal or a multi-layer metal material; The multi-layer metal is selected from any one of LiF and Al, LiO2 and Al, and BaF2 and Al.

Images