Diphenylfluorene organic electroluminescent compound, electroluminescent material and electroluminescent device

Abstract

The invention discloses a diphenylfluorene organic electroluminescent compound, an electroluminescent material and an electroluminescent device, and relates to the technical field of diphenylfluorene organic electroluminescent compounds and materials. According to the diphenylfluorene organic electroluminescent compound, the molecular orbital energy level is optimized, the electron injection and transmission performance is enhanced, and the thermal stability is improved by using a rigid conjugated skeleton. When applied to an electroluminescent device as an electron transport layer material, the compound can significantly reduce driving voltage, improve charge recombination efficiency, and improve luminous efficiency and service life of the device at the same time. The invention also provides an electroluminescent material containing the compound and a device structure, which are suitable for the fields of display and illumination and have the comprehensive advantages of low energy consumption, high brightness and long service life.

Description

Technical Field

[0001] The present invention relates to the technical field of diphenylfluorene-based organic electroluminescent compounds and materials, and specifically relates to a diphenylfluorene-based organic electroluminescent compound, an electroluminescent material, and an electroluminescent device. Background Art

[0002] With the rapid development of technology, organic electroluminescent devices (OLEDs) have become a highly regarded technology in the fields of display and lighting. Due to their self-luminescence, fast response speed, high contrast, wide color gamut, and the ability to achieve flexible display, among other advantages, OLED devices have been widely used in electronic display devices such as smartphones, tablets, and TVs, as well as in new lighting devices. However, current organic electroluminescent technology still faces many challenges.

[0003] From a material perspective, the existing organic electroluminescent materials still need to be further improved in terms of luminous efficiency. Under the action of an electric field, the luminous quantum efficiency of some materials is relatively low, resulting in high energy consumption of the device, which affects the battery life and energy-saving performance of the equipment. At the same time, the insufficient stability of the materials is also a thorny problem. Some organic compounds are prone to degradation, aggregation, etc. under the influence of oxygen, water vapor erosion, and thermal effects during long-term use, accelerating the brightness attenuation of the device and shortening the service life.

[0004] At the device structure level, the problem of balancing charge injection and transport still exists. The lack of matching between efficient electron injection and transport layer materials and hole injection and transport layer materials easily causes unbalanced charge injection, resulting in low charge recombination efficiency in the light-emitting layer, and thus affecting the overall performance of the device. In addition, for large-scale production, the preparation processes of some existing organic electroluminescent materials are complex and costly, restricting the further popularization and cost reduction of OLED devices. Therefore, developing new organic electroluminescent compounds and electroluminescent materials and optimizing the device structure are of great practical significance for promoting the development of organic electroluminescent technology and meeting the growing display and lighting needs. Summary of the Invention

[0005] The object of the present invention is to provide a diphenylfluorene-based organic electroluminescent compound, an electroluminescent material, and an electroluminescent device in view of the problems existing in the prior art. This diphenylfluorene-based organic electroluminescent compound has higher luminous efficiency and better stability, and can effectively solve the problems of low luminous efficiency and poor stability of existing materials.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a diphenylfluorene-based organic electroluminescent compound, and the diphenylfluorene-based organic electroluminescent compound is a compound represented by the following Chemical Formula 1: Chemical Formula 1; X1, X2, and X3 are each independently selected from: N or CH, where at least one of X1, X2, and X3 is N; R1 and R2 are each independently selected from: substituted or unsubstituted C6-C 60 aryl, substituted or unsubstituted C5-C 60 heteroaryl; the C5-C 60 heteroaryl contains any one of N, O, S, or F.

[0007] Furthermore, the unsubstituted C6-C 60 aryl is selected from any one of: phenyl, biphenyl, naphthyl, or hexahydronaphthyl; the substituted C6-C 60 aryl is selected from: phenyl substituted with fluorine or methoxy.

[0008] Furthermore, the substituted C5-C 60 heteroaryl is selected from any one of: dibenzofuranyl, dibenzothiophenyl, or carbazolyl.

[0009] Furthermore, the diphenylfluorene-based organic electroluminescent compound is selected from, but not limited to, the compounds represented by the following E1-E36 structures:

[0010]

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020] .

[0021] An electroluminescent material, the electroluminescent material comprising the above diphenylfluorene-based organic electroluminescent compound.

[0022] An electroluminescent device, which 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 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 includes the above-mentioned electroluminescent material.

[0023] Furthermore, the material of the anode is metal, metal oxide, or conductive polymer.

[0024] Furthermore, the metal is selected from any one of copper, gold, silver, iron, chromium, nickel, or platinum.

[0025] Furthermore, the metal oxide is selected from any one of indium tin oxide, indium zinc oxide, or zinc oxide.

[0026] Furthermore, the conductive polymer is selected from polyaniline or polypyrrole.

[0027] Furthermore, the material of the cathode is metal or multi-layer metal material.

[0028] Furthermore, the multi-layer metal is selected from any one of LiF / Al, LiO2 / Al, BaF2 / Al.

[0029] In the diphenylfluorene-based organic electroluminescent compound of the present invention, the introduction of at least one N atom in X1-X3 significantly affects the molecular orbital energy levels. The high electronegativity of N can reduce the LUMO (lowest unoccupied molecular orbital) energy level, making it closer to the cathode work function, which is beneficial for efficient electron injection from the cathode. The conjugation system of the pyridine ring and 9,9-diphenylfluorene further expands the delocalized electron cloud, improves the electron mobility, and the energy level gradient matches that of the adjacent functional layer (such as the light-emitting layer), reducing the electron transport barrier. The rigid aromatic ring skeleton (pyridine / 9,9-diphenylfluorene) endows the molecule with a high thermal decomposition temperature, meeting the requirements of the evaporation process. The N atom participates in intermolecular hydrogen bond / dipole interactions, inhibits the crystallization tendency, and improves the amorphous film-forming property.

[0030] Compared with the prior art, the beneficial effects of the present invention are: 1. The driving voltage is significantly reduced: Through the optimized design of the molecular structure of the diphenylfluorene-based organic electroluminescent compound, the electron injection and transport efficiency are effectively improved, enabling the device to operate stably at a lower voltage and reducing energy consumption.

[0031] 2. The luminous efficiency is significantly improved: The introduction of a heterocyclic structure enhances the molecular orbital matching degree, promotes the charge recombination efficiency, and improves the electro-optical conversion performance of the device.

[0032] 3. The device life is effectively extended: The rigid molecular backbone and substituents act synergistically to inhibit the crystallization deterioration of the material, improve the thermal stability and anti-aging ability, and extend the service life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic structural diagram of an electroluminescent device according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0035] Example 1 Synthesis of diphenylfluorene-based organic electroluminescent compound E1: ; Synthesis of IM-2: In a 1000 ml three-necked flask, add IM-1 (50 g, 0.11 mol), dissolve it in 500 ml of THF (tetrahydrofuran), cool down to -78 °C, dropwise add n-butyllithium (2.5 M, 50 ML, 0.13 mol), after the addition, keep stirring at -78 °C for 1 hour, dropwise add 200 ml of a tetrahydrofuran solution of methyl isonicotinate (14.4 g, 0.11 mol), naturally warm up to room temperature, stir for 2 hours, take a sample for HPLC detection, the raw material IM-1 < 0.5%, the reaction is complete, add the reaction solution to water, separate the layers, remove the organic phase and concentrate to obtain a crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain intermediate IM-2 (41.7 g, yield 79%).

[0036] Synthesis of E1: In a 1000 ml three-necked flask, add IM-2 (41.7 g, 0.083 mol), dissolve it in 500 ml of THF, cool down to -78 °C, dropwise add n-butyllithium (2.5 M, 40 ML, 0.10 mol), after the addition, keep stirring at -78 °C for 1 hour, dropwise add 200 ml of a tetrahydrofuran solution of methyl 2,6-diphenylisonicotinate (24.0 g, 0.083 mol), naturally warm up to room temperature, stir for 2 hours, take a sample for detection, the raw material IM-2 < 0.5%, the reaction is complete, add the reaction solution to water, separate the layers, remove the organic phase and concentrate to obtain a crude product, and recrystallize with toluene: petroleum ether = 1:2 to obtain E1 (26.6 g, yield 47%).

[0037] Structure test of E1: Mass spectrometry detection, measured m / z: 681; 1HNMR (300 MHz, CDCl3) δ 8.60 - 8.50 (d, 2H), δ 8.30 - 8.20 (d, 4H), δ 8.20 - 8.0 (m, 4H), δ 8.0 - 7.90 (d, 2H), δ 7.60 - 7.40 (m, 8H), δ 7.30 - 7.10 (s, 12H).

[0038] Example 2 Synthesis of diphenylfluorene-based organic electroluminescent compound E2: ; Synthesis of E2: In a 1000 ml three-necked flask, add IM-2 (50 g, 0.10 mol), dissolve it in 500 ml of THF, cool down to -78 °C, dropwise add butyllithium (2.5 M, 48 mL, 0.12 mol). After the addition is complete, stir at -78 °C for 1 hour, then dropwise add 200 ml of a tetrahydrofuran solution of methyl 2,6-diphenylpyrimidine-4-carboxylate (28.9 g, 0.12 mol). Let it warm up to room temperature naturally and stir for 2 hours. Take a sample for detection. The raw material IM-2 < 0.5%, the reaction is complete. Add the reaction solution to water, separate the layers, concentrate the organic phase to obtain a crude product, and recrystallize it with toluene:petroleum ether = 1:2 to obtain E2 (24.4 g, yield 36%).

[0039] Structure test of E2: Detected by mass spectrometry, m / z: 682; 1 HNMR (300 MHz, CDCl3) δ 8.60 - 8.50 (d, 2H), δ 8.30 - 8.20 (d, 2H), δ 8.20 - 8.0 (m, 4H), δ 8.0 - 7.90 (m, 4H), δ 7.60 - 7.40 (m, 9H), δ 7.30 - 7.10 (s, 10H).

[0040] Example 3 Synthesis of diphenylfluorene-based organic electroluminescent compound E3: ; Synthesis of E3: In a 1000 ml three-necked flask, add IM-2 (50 g, 0.10 mol), dissolve it in 500 ml of THF, cool down to -78 °C, dropwise add butyllithium (2.5 M, 48 mL, 0.12 mol). After the addition is complete, stir at -78 °C for 1 hour, then dropwise add 200 ml of a tetrahydrofuran solution of ethyl 4,6-diphenyl-1,3,5-triazine-2-carboxylate (30.4 g, 0.12 mol). Let it warm up to room temperature naturally and stir for 2 hours. Take a sample for detection. The raw material IM-2 < 0.5%, the reaction is complete. Add the reaction solution to water, separate the layers, concentrate the organic phase to obtain a crude product, and recrystallize it with toluene:petroleum ether = 1:2 to obtain E3 (21.4 g, yield 32%).

[0041] Structural test of E3: Mass spectrometry detection, m / z measured: 683; 1 HNMR(300MHz, CDCl3) δ8.60 - 8.50 (d, 2H), δ8.40 - 8.20 (d, 4H), δ8.20 - 8.0 (m, 4H), δ8.0 - 7.90 (d, 2H), δ7.60 - 7.40 (m, 8H), δ7.30 - 7.10 (s, 10H).

[0042] Example 4 Synthesis of diphenylfluorene - based organic electroluminescent compound E4: ; Synthesis of E4: In a 1000 ml three - necked flask, add IM - 2 (50 g, 0.10 mol), dissolve it in 500 ml of THF, cool down to - 78 °C, dropwise add butyllithium (2.5 M, 48 ML, 0.12 mol). After the addition, stir at - 78 °C for 1 hour, then dropwise add 200 ml of a THF solution of methyl 2 - (4 - fluorophenyl)-6 - phenylisonicotinate (30.6 g, 0.12 mol). Let it warm up to room temperature naturally and stir for 2 hours. Take a sample for detection. The raw material IM - 2 < 0.5%, the reaction is complete. Add the reaction solution to water, separate the layers, concentrate the organic phase to obtain a crude product, and recrystallize it with toluene: petroleum ether = 1:2 to obtain E4 (24.3 g, yield 35%).

[0043] Structural test of E4: Mass spectrometry detection, m / z measured: 699; 1 HNMR(300MHz, CDCl3) δ8.60 - 8.50 (d, 2H), δ8.40 - 8.20 (d, 4H), δ8.20 - 8.0 (m, 4H), δ8.0 - 7.90 (d, 2H), δ7.60 - 7.40 (m, 5H), δ7.30 - 7.10 (s, 14H).

[0044] Example 5 Synthesis of diphenylfluorene - based organic electroluminescent compound E16: ; Synthesis of E16: In a 1000 ml three-necked flask, add IM-2 (50 g, 0.10 mol), dissolve it in 500 ml of THF, cool down to -78 °C, dropwise add n-butyllithium (2.5 M, 48 mL, 0.12 mol). After the addition, stir at -78 °C for 1 hour, then dropwise add 200 ml of a tetrahydrofuran solution of methyl 2,6-bis([1,1'-biphenyl]-4-yl)isonicotinate (43.9 g, 0.12 mol). Let it warm up to room temperature naturally and stir for 2 hours. Take a sample for detection. The raw material IM-2 < 0.5%, indicating that the reaction is complete. Add the reaction solution to water, separate the layers, concentrate the organic phase to obtain the crude product, and recrystallize it with toluene:petroleum ether = 1:2 to obtain E16 (22.4 g, yield 27%).

[0045] Structure test of E16: Detected by mass spectrometry, m / z: 833 was measured; 1 HNMR (300 MHz, CDCl3) δ 8.70 - 8.50 (m, 6H), δ 8.40 - 8.20 (d, 4H), δ 8.10 - 7.80 (m, 10H), δ 7.60 - 7.40 (m, 8H), δ 7.30 - 7.10 (s, 12H).

[0046] Example 6 Synthesis of diphenylfluorene-based organic electroluminescent compound E19: ; Synthesis of E19: In a 1000 ml three-necked flask, add IM-2 (50 g, 0.10 mol), dissolve it in 500 ml of THF, cool down to -78 °C, dropwise add n-butyllithium (2.5 M, 48 mL, 0.12 mol). After the addition, stir at -78 °C for 1 hour, then dropwise add 200 ml of a tetrahydrofuran solution of methyl 2-(4-methoxyphenyl)-6-(5,6,7,8-tetrahydronaphthalen-2-yl)isonicotinate (37.2 g, 0.12 mol). Let it warm up to room temperature naturally and stir for 2 hours. Take a sample for detection. The raw material IM-2 < 0.5%, indicating that the reaction is complete. Add the reaction solution to water, separate the layers, concentrate the organic phase to obtain the crude product, and recrystallize it with toluene:petroleum ether = 1:2 to obtain E19 (22.1 g, yield 29%).

[0047] Structure test of E19: Detected by mass spectrometry, m / z: 765 was measured; 1HNMR (300 MHz, CDCl3) δ 8.70 - 8.50 (d, 2H), δ 8.40 - 8.20 (d, 2H), δ 8.10 - 7.90 (m, 4H), δ 7.90 - 7.80 (d, 2H), δ 7.80 - 7.60 (m, 2H), δ 7.60 - 7.40 (d, 2H), δ 7.30 - 7.10 (s, 15H), δ 3.70 (s, 3H), δ 2.80 - 2.60 (m, 4H), δ 1.80 - 1.60 (m, 4H).

[0048] Example 7 Synthesis of diphenylfluorene-based organic electroluminescent compound E26: ; Synthesis of E26: In a 1000 ml three-necked flask, add IM-2 (50 g, 0.10 mol), dissolve it in 500 ml of THF, cool down to -78 °C, dropwise add n-butyllithium (2.5 M, 48 ML, 0.12 mol). After the addition, stir at -78 °C for 1 hour, then dropwise add 200 ml of a tetrahydrofuran solution of methyl 4-(naphthalen-1-yl)-6-phenylpyridine-2-carboxylate (33.8 g, 0.12 mol). Let it warm up to room temperature naturally and stir for 2 hours. Take a sample for detection. When the raw material IM-2 < 0.5%, the reaction is complete. Add the reaction solution into water, separate the layers, concentrate the organic phase to obtain the crude product, and recrystallize it with toluene:petroleum ether = 1:2 to obtain E26 (19.6 g, yield 27%).

[0049] Structure test of E26: Detected by mass spectrometry, m / z: 731; 1 HNMR (300 MHz, CDCl3) δ 8.90 - 8.60 (m, 3H), δ 8.60 - 8.50 (d, 2H), δ 8.50 - 8.20 (m, 5H), δ 8.20 - 7.90 (m, 7H), δ 7.80 - 7.50 (m, 7H), δ 7.30 - 7.10 (s, 10H).

[0050] Example 8 Synthesis of diphenylfluorene-based organic electroluminescent compound E27: ; Synthesis of E27: In a 1000 ml three-necked flask, add IM-2 (50 g, 0.10 mol), dissolve it in 500 ml of THF, cool down to -78 °C, dropwise add butyllithium (2.5 M, 48 mL, 0.12 mol). After the addition, stir at -78 °C for 1 hour, then dropwise add 200 ml of a THF solution of methyl 4-(naphthalen-2-yl)-6-phenylpyridine-2-carboxylate (33.8 g, 0.12 mol). Let it warm up to room temperature naturally and stir for 2 hours. Take a sample for detection. The raw material IM-2 < 0.5%, indicating the reaction is complete. Add the reaction solution to water, separate the layers, remove the organic phase and concentrate it to obtain the crude product. Recrystallize it with toluene:petroleum ether = 1:2 to obtain E27 (18.2 g, yield 25%).

[0051] Structure test of E27: Detected by mass spectrometry, m / z: 731 was measured; 1 HNMR (300 MHz, CDCl3) δ 8.90 - 8.80 (s, 1H), δ 8.60 - 8.50 (d, 2H), δ 8.50 - 8.20 (m, 4H), δ 8.20 - 7.90 (m, 8H), δ 7.80 - 7.50 (m, 9H), δ 7.30 - 7.10 (s, 10H).

[0052] Performance test Device 1 An organic light-emitting device: Use a Sunicsp1710 evaporation machine to fabricate an organic light-emitting device. The specific steps are as follows: 1. Ultrasonically wash a glass substrate (anode) (Corning glass 40 mm × 40 mm × 0.7 mm) coated with 135 nm thick ITO (indium tin oxide) with isopropyl alcohol and pure water for 5 minutes respectively, then clean it with ultraviolet ozone, and then transfer the glass substrate to the vacuum deposition chamber; 2. Vacuum thermally deposit a hole-transporting material HT1 doped with 4% PD with a thickness of 20 nm (about 10-7 Torr) on the transparent ITO electrode to form a hole injection layer; 3. Then vacuum deposit a 120 nm thick compound HT1 on the hole injection layer as the hole-transporting layer; 4. Vacuum deposit 25 nm of BH doped with 4% BD4 by mass fraction as the light-emitting layer on the hole-transporting layer; 5. Vacuum deposit a blend of compound A1 and Liq (mass ratio 50%:50%) on the light-emitting layer to form an electron-transporting layer with a thickness of 30 nm; 6. Deposit a 2 nm thick ytterbium metal (Yb, electron injection layer) and a magnesium-silver alloy with a doping ratio of 10:1 in sequence to form the cathode; 7. 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.

[0053] The structure of the organic electroluminescent element is expressed 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). The schematic diagram of the structure is shown in Figure 1 .

[0054] Device 2 The difference between Device 2 and Device 1 is that compound A2 is used instead of compound A1, and the mass ratio of A1 to Liq is 50%: 50%, and finally an organic electroluminescent element is obtained.

[0055] Device 3 The difference between Device 3 and Device 1 is that compound A3 is used instead of compound A1, and the mass ratio of A1 to Liq is 50%: 50%, and finally an organic electroluminescent element is obtained.

[0056] The structural formulas of the above PD, HT1, BH, BD4, A1, A2, A3, and Liq are as follows: .

[0057] Device 4 The difference between Device 4 and Device 1 is that compound E1 is used instead of compound A1, and the mass ratio of A1 to Liq is 50%: 50%, and finally an organic electroluminescent element is obtained.

[0058] Device 5 The difference between Device 5 and Device 1 is that compound E2 is used instead of compound A1, and the mass ratio of A1 to Liq is 50%: 50%, and finally an organic electroluminescent element is obtained.

[0059] Device 6 The difference between Device 6 and Device 1 is that compound E3 is used instead of compound A1, and the mass ratio of A1 to Liq is 50%: 50%, and finally an organic electroluminescent element is obtained.

[0060] Device 7 The difference between Device 7 and Device 1 is that compound E4 is used instead of compound A1, and the mass ratio of A1 to Liq is 50%: 50%, and finally an organic electroluminescent element is obtained.

[0061] Device 8 The difference between Device 8 and Device 1 is that compound E16 is used instead of compound A1, and the mass ratio of A1 to Liq is 50%: 50%, and finally an organic electroluminescent element is obtained.

[0062] Device 9 The difference between Device 9 and Device 1 is that compound E19 is used to replace compound A1, and the mass ratio of compound A1 to Liq is 50%:50%, and finally an organic electroluminescent device is obtained.

[0063] Device 10 The difference between Device 10 and Device 1 is that compound E26 is used to replace compound A1, and the mass ratio of compound A1 to Liq is 50%:50%, and finally an organic electroluminescent device is obtained.

[0064] Device 11 The difference between Device 11 and Device 1 is that compound E27 is used to replace compound A1, and the mass ratio of compound A1 to Liq is 50%:50%, and finally an organic electroluminescent device is obtained.

[0065] Table 1 Detection Results of Organic Electroluminescent Device Performance

[0066] Compared with the electron transport layer materials A1, A2, and A3, the diphenylfluorene-based organic electroluminescent compound of the present invention can form an ordered arrangement of molecules due to the existence of intermolecular hydrogen bonds by using terminal pyridine and azacyclic molecules, thereby significantly reducing the driving voltage. By using double-substituted electron-withdrawing groups, the energy level matching degree can be improved, the efficiency can be increased, and the device lifetime can be extended. 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.

[0067] 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, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A diphenylfluorene-based organic electroluminescent compound, characterized in that, The diphenylfluorene-based organic electroluminescent compound is a compound represented by the following Chemical Formula 1: Chemical formula 1; X1, X2, and X3 are each independently selected from: N or CH, where at least one of X1, X2, and X3 is N; The R1 and R2 are each independently selected from: substituted or unsubstituted C6-C 60 aryl, substituted or unsubstituted C5-C 60 heteroaryl; The C5-C 60 The heteroaryl contains any one of N, O, S or F.

2. The diphenylfluorene-based organic electroluminescent compound according to claim 1, characterized in that, The unsubstituted C6-C 60 aryl is selected from any one of phenyl, biphenyl, naphthyl or hexahydronaphthyl; The substituted C6-C 60 aryl is selected from: phenyl substituted by fluorine or methoxy group.

3. A diphenylfluorene-based organic electroluminescent compound according to claim 1, wherein The substituted C5-C 60 The heteroaryl is selected from any one of dibenzofuranyl, dibenzothiophenyl or carbazolyl.

4. A diphenylfluorene-based organic electroluminescent compound according to claim 1, characterized in that, The diphenylfluorene-based organic electroluminescent compound is selected from, but not limited to, the compounds represented by the following E1-E36 structures: ； ； ； ； ； ； ； ； ； ； ； 。 5. An electroluminescent material, characterized in that, The electroluminescent material includes the diphenylfluorene-based organic electroluminescent compound according to any one of claims 1-4.

6. 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, 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 includes the electroluminescent material according to claim 5.

7. An electroluminescent device according to claim 6, wherein, The material of the anode is a metal, a metal oxide, or a conductive polymer.

8. An electroluminescent device according to claim 7, characterized in that, The metal is selected from any one of copper, gold, silver, iron, chromium, nickel, or platinum; The metal oxide is selected from any one of indium tin oxide, indium zinc oxide, or zinc oxide; The conductive polymer is selected from polyaniline or polypyrrole.

9. An electroluminescent device according to claim 6, characterized in that, The material of the cathode is a metal or a multi-layer metal material.

10. An electroluminescent device according to claim 9, characterized in that, The multi-layer metal is selected from any one of LiF / Al, LiO2 / Al, BaF2 / Al.

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