A diphenylfluorene organic electroluminescent compound, electroluminescent material and electroluminescent device

Abstract

The present invention discloses a diphenylfluorene-based organic electroluminescent compound, an electroluminescent material, and an electroluminescent device, and relates to the technical field of diphenylfluorene-based organic electroluminescent compounds and materials. The diphenylfluorene-based organic electroluminescent compound optimizes the molecular orbital energy levels, enhances electron injection and transport performance, and utilizes a rigid conjugated skeleton to improve thermal stability. When used as an electron transport layer material in an electroluminescent device, it can significantly reduce the driving voltage, increase the charge recombination efficiency, and improve the luminous efficiency and service life of the device. The present invention also provides an electroluminescent material and device structure containing the compound, which is suitable for the display and lighting fields and has 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 organic electroluminescent compounds and materials, and in particular to a diphenylfluorene organic electroluminescent compound, an electroluminescent material and an electroluminescent device. Background Art

[0002] With the rapid development of science and technology, organic electroluminescent devices (OLEDs) have become a highly anticipated technology in the display and lighting fields. Due to their numerous advantages, including self-luminescence, fast response time, high contrast, wide color gamut, and flexible display capabilities, OLED devices have been widely used in electronic display devices such as smartphones, tablets, and televisions, as well as in new lighting devices. However, OLED technology currently faces numerous challenges.

[0003] From a materials perspective, the luminous efficiency of existing organic electroluminescent materials needs to be further improved. Some materials exhibit low quantum efficiency when exposed to an electric field, resulting in high device energy consumption and impacting device endurance and energy efficiency. Furthermore, insufficient material stability poses a significant challenge. Over long-term use, some organic compounds are susceptible to corrosion by oxygen, water vapor, and thermal effects, leading to degradation and aggregation. This accelerates device brightness decay and shortens device lifespan.

[0004] At the device structure level, the problem of balancing and coordinating charge injection and transport still exists. Insufficient matching of efficient electron injection and transport layer materials and hole injection and transport layer materials can easily lead to uneven charge injection, resulting in low charge recombination efficiency in the light-emitting layer, which in turn affects the overall performance of the device. In addition, for large-scale production, the preparation process of some existing organic electroluminescent materials is complex and costly, which limits the further popularization and cost reduction of OLED devices. Therefore, the development of new organic electroluminescent compounds and electroluminescent materials and the optimization of device structure are of extremely important practical significance for promoting the development of organic electroluminescent technology and meeting the growing demand for display and lighting. Summary of the Invention

[0005] The present invention aims to address the problems of the prior art by providing a diphenylfluorene-based organic electroluminescent compound, an electroluminescent material, and an electroluminescent device. The diphenylfluorene-based organic electroluminescent compound has higher luminous efficiency and better stability, effectively solving 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 organic electroluminescent compound, wherein the diphenylfluorene organic electroluminescent compound is a compound represented by the following chemical formula 1:

[0007] Chemical formula 1;

[0008] Said X1, X2, X3 are each independently selected from: N or CH, wherein at least one of X1, X2, X3 is N;

[0009] Said R1 and R2 are independently selected from: substituted or unsubstituted C6-C 60 Aryl, substituted or unsubstituted C5-C 60 Heteroaryl; the C5-C 60 The heteroaryl group includes any one of N, O, S and F.

[0010] Further, the unsubstituted C6-C 60 Aryl is selected from any one of phenyl, biphenyl and naphthyl; the substituted C6-C 60 Aryl is selected from: phenyl substituted by fluorine or methoxy.

[0011] Further, the substituted C5-C 60 The heteroaryl group is selected from any one of dibenzofuranyl, dibenzothiophenyl and carbazolyl.

[0012] Furthermore, the diphenylfluorene organic electroluminescent compound is selected from but not limited to the compounds shown in the following structures E1-E36:

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024] .

[0025] An electroluminescent material comprises the above-mentioned diphenylfluorene organic electroluminescent compound.

[0026] An electroluminescent device comprising a cathode, an anode, and a light-emitting layer located between the cathode and the anode;

[0027] 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;

[0028] 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;

[0029] The material of the electron transport layer includes the above-mentioned electroluminescent material.

[0030] Furthermore, the material of the anode is metal, metal oxide or conductive polymer.

[0031] Furthermore, the metal is selected from any one of copper, gold, silver, iron, chromium, nickel or platinum.

[0032] Furthermore, the metal oxide is selected from any one of indium tin oxide, indium zinc oxide or zinc oxide.

[0033] Furthermore, the conductive polymer is selected from polyaniline or polypyrrole.

[0034] Furthermore, the cathode is made of metal or multilayer metal material.

[0035] Furthermore, the multilayer metal is selected from any one of LiF / Al, LiO2 / Al, and BaF2 / Al.

[0036] The introduction of at least one N atom in X1-X3 in the diphenylfluorene organic electroluminescent compound described in the present invention significantly affects the molecular orbital energy level. 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 conducive to the efficient injection of electrons from the cathode. The conjugated system of the pyridine ring and 9,9-diphenylfluorene further expands the delocalized electron cloud, improves electron mobility, and matches the energy level gradient with the adjacent functional layer (such as the light-emitting layer), reducing the electron transport barrier. The rigid aromatic ring skeleton (pyridine / 9,9-diphenylfluorene) gives the molecule a high thermal decomposition temperature, which meets the requirements of the evaporation process. The N atom participates in the intermolecular hydrogen bond / dipole interaction, inhibits the crystallization tendency, and improves the amorphous film-forming property.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. Driving voltage is significantly reduced: Through the optimized design of the molecular structure of diphenylfluorene organic electroluminescent compounds, the electron injection and transmission efficiency is effectively improved, the device can be operated stably at a lower voltage, and energy consumption is reduced.

[0039] 2. Significantly improved luminous efficiency: The introduction of heterocyclic structures enhances molecular orbital matching, promotes charge recombination efficiency, and improves the electro-optical conversion performance of the device.

[0040] 3. Effectively extend the life of the device: The rigid molecular skeleton and the substituents work synergistically to inhibit the crystallization degradation of the material, improve thermal stability and anti-aging ability, and extend the service life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic structural diagram of an electroluminescent device according to the present invention. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] Example 1

[0044] Synthesis of diphenylfluorene organic electroluminescent compound E1:

[0045] ;

[0046] Synthesis of IM-2: IM-1 (50 g, 0.11 mol) was added to a 1000 ml three-necked flask and dissolved in 500 ml of THF (tetrahydrofuran). The temperature was lowered to -78 ° C. Butyl lithium (2.5 M, 50 ml, 0.13 mol) was added dropwise. After the addition was complete, the mixture was stirred at -78 ° C for 1 hour. 200 ml of a tetrahydrofuran solution of methyl isonicotinate (14.4 g, 0.11 mol) was added dropwise. The mixture was naturally warmed to room temperature and stirred for 2 hours. A sample was taken for HPLC detection. The raw material IM-1 was <0.5%, and the reaction was complete. The reaction solution was added to water, separated, and the organic phase was concentrated to obtain a crude product. The crude product was recrystallized from toluene: petroleum ether = 1:2 to obtain the intermediate IM-2 (41.7 g, yield 79%).

[0047] Synthesis of E1: IM-2 (41.7 g, 0.083 mol) was added to a 1000 ml three-necked flask and dissolved in 500 ml of THF. The temperature was lowered to -78 ° C. Butyl lithium (2.5 M, 40 ml, 0.10 mol) was added dropwise. After the addition was completed, the temperature was kept at -78 ° C. and stirred for 1 hour. 200 ml of a tetrahydrofuran solution of methyl 2,6-diphenylisonicotinate (24.0 g, 0.083 mol) was added dropwise. The temperature was naturally raised to room temperature and stirred for 2 hours. After sampling and detection, the raw material IM-2 was <0.5%, and the reaction was complete. The reaction solution was added to water, separated, and the organic phase was concentrated to obtain a crude product. E1 (26.6 g, yield 47%) was recrystallized from toluene: petroleum ether = 1:2.

[0048] Structural analysis of E1: mass spectrometry, m / z: 681; 1 HNMR (300MHz, CDCl3) δ8.60-8.50 (d, 2H), δ8.30-8.20 (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, 12H).

[0049] Example 2

[0050] Synthesis of diphenylfluorene organic electroluminescent compound E2:

[0051] ;

[0052] Synthesis of E2: IM-2 (50 g, 0.10 mol) was added to a 1000 ml three-necked flask and dissolved in 500 ml of THF. The temperature was lowered to -78 ° C, and butyl lithium (2.5 M, 48 ml, 0.12 mol) was added dropwise. After the addition was complete, the temperature was kept at -78 ° C and stirred for 1 hour. 200 ml of a tetrahydrofuran solution of methyl 2,6-diphenylpyrimidine-4-carboxylate (28.9 g, 0.12 mol) was added dropwise. The temperature was naturally raised to room temperature and stirred for 2 hours. After sampling and testing, the raw material IM-2 was <0.5%, and the reaction was complete. The reaction solution was added to water, separated, and the organic phase was concentrated to obtain a crude product. E2 (24.4 g, yield 36%) was recrystallized from toluene: petroleum ether = 1:2.

[0053] Structural analysis of E2: mass spectrometry, m / z: 682; 1 HNMR (300MHz, CDCl3) δ8.60-8.50 (d, 2H), δ8.30-8.20 (d, 2H), δ8.20-8.0 (m, 4H), δ8.0-7.90 (m, 4H), δ7.60-7.40 (m, 9H), δ7.30-7.10 (s, 10H).

[0054] Example 3

[0055] Synthesis of diphenylfluorene organic electroluminescent compound E3:

[0056] ;

[0057] Synthesis of E3: IM-2 (50 g, 0.10 mol) was added to a 1000 ml three-necked flask, dissolved in 500 ml of THF, cooled to -78 ° C, and butyl lithium (2.5 M, 48 ml, 0.12 mol) was added dropwise. After the addition was completed, the temperature was kept at -78 ° C and stirred for 1 hour. 200 ml of a tetrahydrofuran solution of ethyl 4,6-diphenyl-1,3,5-triazine-2-carboxylate (30.4 g, 0.12 mol) was added dropwise, and the temperature was naturally raised to room temperature. Stir for 2 hours and sampled for detection. The raw material IM-2 was <0.5%, and the reaction was complete. The reaction solution was added to water, separated, and the organic phase was concentrated to obtain a crude product, which was recrystallized from toluene: petroleum ether = 1:2 to obtain E3 (21.4 g, yield 32%).

[0058] Structural analysis of E3: mass spectrometry, m / z: 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).

[0059] Example 4

[0060] Synthesis of diphenylfluorene organic electroluminescent compound E4:

[0061] ;

[0062] Synthesis of E4: IM-2 (50 g, 0.10 mol) was added to a 1000 ml three-necked flask and dissolved in 500 ml of THF. The temperature was lowered to -78 ° C. Butyl lithium (2.5 M, 48 ml, 0.12 mol) was added dropwise. After the addition was completed, the temperature was kept at -78 ° C. and stirred for 1 hour. 200 ml of a tetrahydrofuran solution of methyl 2-(4-fluorophenyl)-6-phenylisonicotinate (30.6 g, 0.12 mol) was added dropwise. The temperature was naturally raised to room temperature and stirred for 2 hours. After sampling and detection, the raw material IM-2 was <0.5%, and the reaction was complete. The reaction solution was added to water, separated, and the organic phase was concentrated to obtain a crude product, which was recrystallized from toluene: petroleum ether = 1:2 to obtain E4 (24.3 g, yield 35%).

[0063] Structural analysis of E4: mass spectrometry, m / z: 699; 1HNMR (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).

[0064] Example 5

[0065] Synthesis of diphenylfluorene organic electroluminescent compound E16:

[0066] ;

[0067] Synthesis of E16: IM-2 (50 g, 0.10 mol) was added to a 1000 ml three-necked flask and dissolved in 500 ml of THF. The temperature was lowered to -78 ° C. Butyl lithium (2.5 M, 48 ml, 0.12 mol) was added dropwise. After the addition was complete, the temperature was kept at -78 ° C. and stirred for 1 hour. 200 ml of a tetrahydrofuran solution of methyl 2,6-bis([1,1'-biphenyl]-4-yl)isonicotinate (43.9 g, 0.12 mol) was added dropwise. The temperature was naturally raised to room temperature and stirred for 2 hours. Sampling was performed for detection. The raw material IM-2 was <0.5%, indicating that the reaction was complete. The reaction solution was added to water, separated, and the organic phase was concentrated to obtain a crude product. E16 (22.4 g, 27% yield) was recrystallized from toluene: petroleum ether = 1:2.

[0068] Structural analysis of E16: mass spectrometry, m / z: 833; 1 HNMR (300MHz, CDCl3) δ8.70-8.50 (m, 6H), δ8.40-8.20 (d, 4H), δ8.10-7.80 (m, 10H), δ7.60-7.40 (m, 8H), δ7.30-7.10 (s, 12H).

[0069] Example 6

[0070] Synthesis of diphenylfluorene organic electroluminescent compound E19:

[0071] ;

[0072] Synthesis of E19: IM-2 (50 g, 0.10 mol) was added to a 1000 ml three-necked flask and dissolved in 500 ml of THF. The temperature was lowered to -78 ° C. Butyl lithium (2.5 M, 48 ml, 0.12 mol) was added dropwise. After the addition was completed, the temperature was kept at -78 ° C. and stirred for 1 hour. 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) was added dropwise. The temperature was naturally raised to room temperature and stirred for 2 hours. Sampling was performed for detection. The raw material IM-2 was <0.5%, and the reaction was complete. The reaction solution was added to water, separated, and the organic phase was concentrated to obtain a crude product. E19 (22.1 g, yield 29%) was recrystallized from toluene: petroleum ether = 1:2.

[0073] Structural analysis of E19: mass spectrometry, m / z: 765; 1 HNMR (300MHz, CDCl3) δ8.70-8.50 (d, 2H), δ8.40-8.20 (d, 2H), δ8.10-7.90 (m, 4H), δ7.90-7.80 (d, 2H), δ7.80- 7.60 (m, 2H), δ7.60-7.40 (d, 2H), δ7.30-7.10 (s, 15H), δ3.70 (s, 3H), δ2.80-2.60 (m, 4H), δ1.80-1.60 (m, 4H).

[0074] Example 7

[0075] Synthesis of diphenylfluorene organic electroluminescent compound E26:

[0076] ;

[0077] Synthesis of E26: IM-2 (50 g, 0.10 mol) was added to a 1000 ml three-necked flask and dissolved in 500 ml of THF. The temperature was lowered to -78 ° C. Butyl lithium (2.5 M, 48 ml, 0.12 mol) was added dropwise. After the addition was completed, the temperature was kept at -78 ° C. and stirred for 1 hour. 200 ml of a tetrahydrofuran solution of methyl 4-(naphthalen-1-yl)-6-phenylpicolinate (33.8 g, 0.12 mol) was added dropwise. The temperature was naturally raised to room temperature and stirred for 2 hours. After sampling and testing, the raw material IM-2 was <0.5%, and the reaction was complete. The reaction solution was added to water, separated, and the organic phase was concentrated to obtain a crude product, which was recrystallized from toluene: petroleum ether = 1:2 to obtain E26 (19.6 g, yield 27%).

[0078] Structural analysis of E26: Mass spectrometry, m / z: 731; 1HNMR (300MHz, CDCl3) δ8.90-8.60 (m, 3H), δ8.60-8.50 (d, 2H), δ8.50-8.20 (m, 5H), δ8.20-7.90 (m, 7H), δ7.80-7.50 (m, 7H), δ7.30-7.10 (s, 10H).

[0079] Example 8

[0080] Synthesis of diphenylfluorene organic electroluminescent compound E27:

[0081] ;

[0082] Synthesis of E26: IM-2 (50 g, 0.10 mol) was added to a 1000 ml three-necked flask and dissolved in 500 ml of THF. The temperature was lowered to -78 ° C. Butyl lithium (2.5 M, 48 ml, 0.12 mol) was added dropwise. After the addition was completed, the temperature was kept at -78 ° C. and stirred for 1 hour. 200 ml of a tetrahydrofuran solution of methyl 4-(naphthalene-2-yl)-6-phenylpicolinate (33.8 g, 0.12 mol) was added dropwise. The temperature was naturally raised to room temperature and stirred for 2 hours. After sampling and testing, the raw material IM-2 was <0.5%, and the reaction was complete. The reaction solution was added to water, separated, and the organic phase was concentrated to obtain a crude product, which was recrystallized from toluene: petroleum ether = 1:2 to obtain E27 (18.2 g, yield 25%).

[0083] Structural analysis of E27: mass spectrometry, m / z: 731; 1 HNMR (300MHz, CDCl3) δ8.90-8.80 (s, 1H), δ8.60-8.50 (d, 2H), δ8.50-8.20 (m, 4H), δ8.20-7.90 (m, 8H), δ7.80-7.50 (m, 9H), δ7.30-7.10 (s, 10H).

[0084] Performance Testing

[0085] Device 1

[0086] An organic electroluminescent device:

[0087] An organic electroluminescent device is manufactured using a Sunicsp1710 evaporation machine. The specific steps are as follows:

[0088] 1. A glass substrate (anode) coated with 135 nm thick ITO (indium tin oxide) (Corning glass, 40 mm × 40 mm × 0.7 mm) was ultrasonically cleaned with isopropyl alcohol and pure water for 5 minutes each, then cleaned with ultraviolet ozone. The glass substrate was then transferred to a vacuum deposition chamber.

[0089] 2. HT1, a hole transport material doped with 4% PD, was thermally deposited on the transparent ITO electrode in a vacuum (approximately 10-7 Torr) with a thickness of 20 nm to form a hole injection layer;

[0090] 3. Compound HT1 was then vacuum deposited to a thickness of 120 nm on the hole injection layer to serve as a hole transport layer;

[0091] 4. Vacuum deposit 25nm of BH doped with 4% BD4 as the light-emitting layer on the hole transport layer;

[0092] 5. Vacuum deposit a mixture of compound A1 and Liq (mass ratio of 50%:50%) on the light-emitting layer to form an electron transport layer with a thickness of 30 nm.

[0093] 6. Deposit 2nm thick ytterbium (Yb, electron injection layer) and magnesium-silver alloy with a doping ratio of 10:1 to form a cathode in sequence;

[0094] 7. Finally, the device is transferred from the deposition chamber to a glove box and then encapsulated with UV-curable epoxy resin and a glass cover containing a moisture absorbent to obtain an organic electroluminescent device.

[0095] The structure of the organic electroluminescent element is: ITO (135nm) / HT1:4%HD (20nm) / HT1 (120nm) / BH:4%BD4 (25nm) / A1:Liq (50%:50%, 30nm) / Yb (2 nm) / Mg:Ag (10:1, 150nm). See the schematic diagram of the structure. Figure 1 .

[0096] Device 2

[0097] The difference between device 2 and device 1 is that compound A2 is used instead of compound A1 and the mass ratio of compound A2 to Liq is 50%:50%, and an organic electroluminescent element is finally obtained.

[0098] Device 3

[0099] The difference between device 3 and device 1 is that compound A3 is used instead of compound A1 and the mass ratio of compound A3 to Liq is 50%:50%, and an organic electroluminescent element is finally obtained.

[0100] The structural formulas of the above-mentioned PD, HT1, BH, BD4, A1, A2, A3 and Liq are as follows:

[0101] .

[0102] Device 4

[0103] The difference between device 4 and device 1 is that compound E1 is used instead of compound A1 and the mass ratio of compound E1 to Liq is 50%:50%, and an organic electroluminescent element is finally obtained.

[0104] Device 5

[0105] The difference between device 5 and device 1 is that compound E2 is used instead of compound A1 and the mass ratio of compound E2 to Liq is 50%:50%, and an organic electroluminescent element is finally obtained.

[0106] Device 6

[0107] The difference between device 6 and device 1 is that compound E3 is used instead of compound A1 and the mass ratio of compound E3 to Liq is 50%:50%, and an organic electroluminescent element is finally obtained.

[0108] Device 7

[0109] The difference between device 7 and device 1 is that compound E4 is used instead of compound A1 and the mass ratio of compound E4 to Liq is 50%:50%, and an organic electroluminescent element is finally obtained.

[0110] Device 8

[0111] The difference between device 8 and device 1 is that compound E16 is used instead of compound A1 and the mass ratio of compound E16 to Liq is 50%:50%, and an organic electroluminescent element is finally obtained.

[0112] Device 9

[0113] The difference between device 9 and device 1 is that compound E19 is used instead of compound A1 and the mass ratio of compound E19 to Liq is 50%:50%, and an organic electroluminescent element is finally obtained.

[0114] Device 10

[0115] The difference between device 10 and device 1 is that compound E26 is used instead of compound A1 and the mass ratio of compound E26 to Liq is 50%:50%, and an organic electroluminescent element is finally obtained.

[0116] Device 11

[0117] The difference between device 11 and device 1 is that compound E27 is used instead of compound A1 and the mass ratio of compound E27 to Liq is 50%:50%, and an organic electroluminescent element is finally obtained.

[0118] Table 1 Performance test results of organic electroluminescent devices

[0119]

[0120] Compared to electron transport layer materials A1, A2, and A3, the diphenylfluorene-based organic electroluminescent compound of the present invention utilizes terminal pyridines and nitrogen heterocyclic molecules. Due to the presence of intermolecular hydrogen bonds, the molecular paths are arranged in an orderly manner, thereby significantly reducing the driving voltage. The use of disubstituted electron-withdrawing groups improves energy level matching, increases efficiency, and extends device life. This provides an organic electroluminescent device that exhibits high luminous efficiency and a long operating life while maintaining a relatively low driving voltage, thereby improving power efficiency and power consumption, and extending device life.

[0121] While 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 these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A diphenylfluorene-based organic electroluminescent compound, characterized in that: The diphenylfluorene organic electroluminescent compound is a compound represented by the following chemical formula 1: Chemical formula 1; Said X1, X2, X3 are each independently selected from: N or CH, wherein at least one of X1, X2, X3 is N; The R1 and R2 are independently selected from any one of phenyl, biphenyl, naphthyl, phenyl substituted by fluorine or methoxy, dibenzofuranyl, dibenzothiophenyl or carbazolyl.

2. The diphenylfluorene organic electroluminescent compound according to claim 1, characterized in that: The diphenylfluorene organic electroluminescent compound is selected from the compounds shown in the following structures E1-E36: ； ； ； ； ； ； ； ； ； ； 。 3. An electroluminescent material, characterized in that The electroluminescent material comprises the diphenylfluorene organic electroluminescent compound according to any one of claims 1 to 2.

4. 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 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 3.

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

6. An electroluminescent device according to claim 5, 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.

7. An electroluminescent device according to claim 4, characterized in that: The cathode is made of metal or multi-layer metal material.

8. An electroluminescent device according to claim 7, characterized in that: The multilayer metal is selected from any one of LiF / Al, LiO2 / Al, and BaF2 / Al.

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