An organic electroluminescent material and an organic electroluminescent device containing the same

Abstract

The present invention belongs to the field of organic photoelectric materials, and discloses an organic electroluminescent material and an organic electroluminescent device containing the same. The structure of the organic electroluminescent material is shown in Formula I: The organic electroluminescent material provided by the present invention is used as a material in the light-emitting layer of the organic electroluminescent device, which can reduce the driving voltage of the device, improve the maximum external quantum efficiency of the device, and extend the phosphorescence life of the device.

Description

Technical Field

[0001] The invention belongs to the field of organic photoelectric materials, and in particular relates to an organic electroluminescent material and an organic electroluminescent device containing the same. Background Art

[0002] OLED is a self-luminous solid-state device that offers great potential for display and lighting applications. OLEDs can be divided into three different types based on their light-emitting mechanism. The OLED invented by Tang and van Slyke is a fluorescent OLED. Because it only uses singlet states to emit light, the triplet states generated in the device are wasted through non-radiative decay channels. Therefore, the internal quantum efficiency (IQE) of fluorescent OLEDs is only 25%, which has hindered the commercialization of OLEDs.

[0003] In 1997, Forrest and Thompson reported phosphorescent OLEDs that used triplet emission from heavy metal containing complexes as emitters to enable harvesting of singlet and triplet states, achieving an IQE of 100%. Due to its high efficiency, the discovery and development of phosphorescent OLEDs directly contributed to the commercialization of active matrix OLEDs (AMOLEDs).

[0004] At present, green phosphorescent materials still have the problems of low luminescent quantum efficiency and poor color purity. The main reason for this situation is that phosphorescence comes from the transition between energy levels with a narrow energy gap, and there are certain difficulties in the design of ligands for narrow-bandgap heavy metal complexes. Secondly, there is a strong π-π bond interaction in the system of phosphorescent materials, and there is a strong charge transfer characteristic between ligands, which makes more radiation-free relaxation channels exist in the narrow band gap, aggravates the quenching of phosphors, and reduces the quantum yield and molecular stability of phosphorescent systems. Therefore, designing and synthesizing green phosphorescent materials with excellent comprehensive performance will become an important topic in the research of organic electroluminescent materials. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention discloses an organic electroluminescent material and an organic electroluminescent device comprising the same. The organic electroluminescent material provided by the present invention is used as a material in the light-emitting layer of the organic electroluminescent device, so that the driving voltage of the device can be reduced, the maximum external quantum efficiency of the device can be improved, and the phosphorescence life of the device can be prolonged.

[0006] In order to achieve the above-mentioned purpose, the first object of the present invention is to provide an organic electroluminescent material. The following technical scheme is adopted:

[0007] An organic electroluminescent material having a structure shown in general formula I:

[0008] ;

[0009] Among them, R1, R2, R3, R4, R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 each independently selected from hydrogen, deuterium, halogen, substituted or unsubstituted alkyl having 1 to 20 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 20 carbon atoms, substituted or unsubstituted heterocyclyl having 3 to 20 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 6 to 30 carbon atoms, substituted or unsubstituted alkoxy having 1 to 20 carbon atoms, substituted or unsubstituted aryloxy having 6 to 30 carbon atoms, silanyl, germyl, and combinations thereof;

[0010] At least one of R5, R6, R7 and R8 is not hydrogen, and each is independently selected from hydrogen, deuterium, fluoro, cyano, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted isopropyl, substituted or unsubstituted n-butyl, substituted or unsubstituted isobutyl, substituted or unsubstituted tert-butyl, substituted or unsubstituted sec-butyl, substituted or unsubstituted n-pentyl, substituted or unsubstituted neopentyl, substituted or unsubstituted isopentyl, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted aryl having 6 to 18 carbon atoms, substituted or unsubstituted heteroaryl having 6 to 18 carbon atoms, and combinations thereof;

[0011] R9 and R 10 Each is independently selected from hydrogen, deuterium, fluorine, cyano, -CD3, methyl, ethyl, propyl, isobutyl, tert-butyl, isopentyl, cyclopentyl, and cyclohexyl.

[0012] Furthermore, the hydrogen atoms in the above groups may be partially or fully deuterated.

[0013] It should be noted that the above-mentioned substituted or unsubstituted is substituted by one, two or more substituents selected from the following: deuterium; halogen group; cyano group; C1-C6 alkyl group; C3-C10 cycloalkyl group; alkoxy group; C6-C18 aryl group; C3-C24 heterocyclic group, or is substituted by a substituent connected by two or more substituents shown above, or has no substituent.

[0014] Furthermore, Formula I has the structure shown in Formula a-Formula d: ;

[0015] Among them, R1, R2, R3, R4, R 11 , R12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 Each is independently selected from hydrogen, deuterium, cyano, -CD3, -CD2CD3, -(CD3)3, -F, methyl, ethyl, propyl, butyl, pentyl, cyclopropyl, cyclobutyl, cyclopentyl, methoxy, ethoxy, phenyl, naphthyl or the following groups:

[0016] ;

[0017] At least one of R5, R6, R7 and R8 is not hydrogen, and each is independently selected from hydrogen, deuterium, -F, -CN, -CD3, -CD2CD3, -(CD3)3, methyl, ethyl, propyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, cyclopentyl, cyclohexyl, phenyl, biphenyl, naphthyl or the following groups:

[0018] .

[0019] Furthermore, the alkyl group and the aryl group may be partially or fully deuterated.

[0020] Furthermore, the LA ligand Select from the following structures: .

[0021] Furthermore, the LB ligand Select from the following structures: .

[0022] In the present invention, the organic electroluminescent material is selected from any one of the following structures: .

[0023] Only some specific structural forms are listed above, but this series of organic electroluminescent materials is not limited to the above molecular structures. Other specific molecular structures can be obtained by simple changes of some simple groups and their substituted groups and substitution positions, which will not be described one by one here.

[0024] The second object of the present invention is to provide application of the above organic electroluminescent material in an organic electroluminescent device.

[0025] The present invention provides an organic electroluminescent device, comprising the organic electroluminescent material as described above.

[0026] The organic electroluminescent device comprises an anode, a cathode and an organic layer disposed between the anode and the cathode, wherein the organic layer contains the organic electroluminescent material of the present invention; the organic electroluminescent material is in a single form or mixed with other substances and exists in the organic layer.

[0027] The organic layer at least includes a hole injection layer, a hole transport layer, a layer having both hole injection and hole transport skills, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer and a layer having both electron transport and electron injection skills, or a combination of at least two of them.

[0028] The organic electroluminescent device comprises at least one functional layer, namely, the organic electroluminescent material of the present invention.

[0029] The organic electroluminescent device comprises a light-emitting layer, and the light-emitting layer contains the organic electroluminescent material of the present invention.

[0030] The light-emitting layer of the organic electroluminescent device includes a main material and a doping material, wherein the doping material is the organic electroluminescent material of the present invention, and the mixing mass ratio of the main material to the doping material is 90:10 to 99.5:0.5, for example, 90:10, 91:9, 92:8, 93:7, 94:6, 95:5, 96:4, 97:3, 98:2 or 99:1, etc.

[0031] The device of the present invention can be used in organic light-emitting devices, organic solar cells, electronic paper, organic photoreceptors or organic thin film transistors.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention provides an organic electroluminescent material. By selecting a specific heterocyclic ligand for coordination and changing the position of a substituent or the activity of a substituent, the obtained organic electroluminescent material is used in an organic electroluminescent device, and the maximum external quantum efficiency of the device is improved, the life span is prolonged, and the driving voltage is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0035] Figure 1 This is the G-695 hydrogen nuclear magnetic resonance spectrum. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention and the related drawings. 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.

[0037] The invention specifically discloses an organic electroluminescent material and an organic electroluminescent device containing the same.

[0038] The features and performance of the present invention will be further described in detail below with reference to the embodiments.

[0039] Example 1 Preparation of G-597

[0040] ;

[0041] Step 1: Under a nitrogen atmosphere, 1-bromo-2,4,6-triphenylbenzene (1 eq), (6-bromodibenzo[b,d]furan-3-yl)boric acid (1.1 eq), and anhydrous potassium carbonate (3 eq) were added to the phase system in sequence, dissolved in a mixed solution of toluene, ethanol, and water (volume ratio 2:1:1), and nitrogen was replaced twice. Under nitrogen protection, tetrakis(triphenylphosphine)palladium (3% eq) was added to the phase system, and nitrogen was replaced twice. The system was heated to 75°C and refluxed for 10 hours. The heating was turned off, and the system was cooled to room temperature. The system was allowed to stand for separation, and the aqueous phase was extracted twice with ethyl acetate. The organic phases were combined, washed three times with water, and dried by spin column chromatography. A mixture of petroleum ether and dichloromethane was used as an eluent to obtain intermediate S3 with a yield of 31.64%.

[0042] Mass spectrometry test value: 550.14;

[0043] HPLC: ≥99.8%

[0044] ;

[0045] Step 2: Under nitrogen atmosphere, add intermediate S3 (1 eq), pyridine-2-boric acid (1.2 eq), and anhydrous potassium carbonate (3 eq) to the phase system in sequence, dissolve in a mixed solution of toluene, ethanol, and water (volume ratio 2:1:1), replace nitrogen twice, add tetrakis(triphenylphosphine)palladium (2% eq) to the phase system under nitrogen protection, replace nitrogen twice, heat to 85°C and reflux for reaction for 12 hours, turn off the heating, cool to room temperature, stand and separate the liquids, extract the aqueous phase twice with ethyl acetate, combine the organic phases, wash three times with water, spin dry, and column chromatograph, using a mixture of petroleum ether and ethyl acetate as eluent to obtain intermediate S4, with a yield of 46.79%.

[0046] Mass spectrometry test value: 549.34;

[0047] HPLC: ≥99.5%;

[0048] 1 H NMR (400 MHz, deuterated chloroform) δ 8.57 (dd, 1H), 8.14 (dd, 1H), 8.06 (dt,1H), 7.96 (d, 1H), 7.78 (dd, 1H), 7.71 (ddd, 1H), 7.67 – 7.57 (m, 9H), 7.55 –7.34 (m, 11H), 7.24 (ddd, 1H).

[0049] ;

[0050] Step 3: Add intermediate S4 (1 eq) and tetrahydrofuran (40 eq) to the reaction system in sequence. When the temperature in the reaction system drops to -78°C, slowly add lithium diisopropylamide (2 eq) to the reaction system. The temperature is controlled at -78°C during the addition. After the addition is completed, keep the temperature for 4 hours. After the reaction is completed, naturally warm it to room temperature. Add heavy water (50 ml) to the reaction system to quench, extract the aqueous phase with ethyl acetate, combine the organic phases, concentrate, column chromatography, use a mixture of petroleum ether and dichloromethane as the eluent, and concentrate to obtain intermediate S5 with a yield of 51.4%.

[0051] Mass spectrometry test value: 550.21;

[0052] HPLC: ≥99.6%;

[0053] ;

[0054] Step 4: Under nitrogen protection, weigh A-597 (2.2 eq) and IrC13•3H2O (1 eq) into the reaction system, dissolve in a mixed solution of ethylene glycol ethyl ether and water (volume ratio 3:1), reflux for 48 hours under nitrogen protection, then cool to room temperature, and precipitate is precipitated. Filter the precipitate, rinse and dry it with water, anhydrous ethanol and petroleum ether in turn to obtain the bridging ligand B-597 with a yield of 94.02%.

[0055] Step 5: Weigh the bridging ligand B-597 (1 eq), add silver trifluoromethanesulfonate (2.2 eq), dissolve in a mixed solution of dichloromethane and methanol (volume ratio 2:1), react at 25 ° C for 48 hours under nitrogen protection, pass through a silica gel funnel, and spin dry to obtain the intermediate C-597 with a yield of 95.12%.

[0056] Step 6: Weigh the intermediate C-597 (1 eq), add the ligand S5 (2.5 eq), dissolve in anhydrous ethanol solvent, reflux for 48 hours under nitrogen protection, filter, wash with alcohol, and dry; use a mixture of petroleum ether and dichloromethane as eluent, column chromatography, concentrate the filtrate and precipitate the solid to obtain the organic electroluminescent material G-597, yield: 35.53%.

[0057] Mass spectrometry test value: 1084.45;

[0058] HPLC: ≥99.4%

[0059] 1 H NMR (400 MHz, deuterated chloroform) δ 8.57 (dd, 1H), 8.04 (d, 2H), 7.86 (d,2H), 7.74 (td, 1H), 7.70 – 7.67 (m, 2H), 7.67 – 7.63 (m, 4H), 7.62 (s, 2H),7.58 (s, 1H), 7.55 (dd, 2H), 7.50 – 7.44 (m, 3H), 7.37 – 7.19 (m, 19H).

[0060] Theoretical value of elemental analysis: C, 72.00%; H, 4.93%; N, 3.88%; O, 1.48%; tested value: C, 72.02%; H, 4.95%; N, 3.87%; O, 1.45%.

[0061] Example 2 Preparation of G-695

[0062] ;

[0063] Step 1: Under a nitrogen atmosphere, DMSO (50 ml), potassium phosphate trihydrate (2 eq), pyridine-2-carboxylic acid (1% eq) and CuI (5% eq) were added to the reaction system, followed by gradual addition of 2-chloro-3-fluorophenol (1.2 eq) and 2-bromo-1-chlorobenzene (1 eq), and the reaction mixture was heated at 85° C. for 16 h; after cooling, the reaction mixture was extracted with an ammonia solution and methyl tert-butyl ether, and the organic phase was washed five times with water and then twice with a saturated NaCl solution; finally, the combined organic phase was dried over anhydrous Na2SO4, concentrated, and fractionated to obtain intermediate S6 with a yield of 51.6%;

[0064] Mass spectrometry test value: 256.12;

[0065] HPLC: ≥99.4%.

[0066] 1 H NMR (400 MHz, deuterated chloroform) δ 7.36 (dd, 1H), 7.27 – 7.19 (m, 2H), 7.07(td, 1H), 7.00 – 6.91 (m, 2H), 6.87 (dd, 1H).

[0067] ;

[0068] Step 2: Under nitrogen atmosphere, S6 (1 eq) was added to tetrahydrofuran (150 ml), and when the temperature was lowered to -78°C, n-butyl lithium (2.5 mol / l hexane solution, 80 ml, 2 eq) was added dropwise to the system, and the internal temperature was controlled not to exceed -65°C during the addition, and the addition was completed. Stirring was continued at -75°C for 4 h, and bromine (2.5 eq) was added dropwise to the system, and the internal temperature was controlled not to exceed -65°C, and the addition was completed. The mixture was stirred at -78°C for 1 h, then gradually heated to 10°C and stirred at 10°C for 1 h. It was cooled to 0°C and quenched with saturated Na2SO3 solution (50 ml). The mixture was extracted with toluene and water, and the combined organic phase was washed three times with water and once with saturated NaCl solution, dried with Na2SO4, and the solvent was removed on a rotary evaporator. The crude product was extracted twice with 2-propanol with stirring and refluxing to obtain intermediate S7, with a yield of 55.98%.

[0069] Mass spectrometry test value: 341.92;

[0070] HPLC: ≥99.2%.

[0071] ;

[0072] Step 3: Under a nitrogen atmosphere, the intermediate S7 (1 eq), 5-methylpyridine-2-boric acid (1.2 eq), and anhydrous potassium carbonate (3 eq) were sequentially added to the phase system and dissolved in a mixed solution of toluene, ethanol, and water (volume ratio 3:1:1). Under nitrogen protection, tetrakis(triphenylphosphine)palladium (2% eq) was added to the phase system, and the nitrogen was replaced twice. The system was heated to 85°C and refluxed for 12 hours. The heating was turned off, and the system was cooled to room temperature. The system was allowed to stand for separation, and the aqueous phase was extracted twice with ethyl acetate. The organic phases were combined, washed with water three times, spin-dried, and subjected to column chromatography. A mixture of petroleum ether and ethyl acetate was used as the eluent to obtain the intermediate S8 with a yield of 46.84%.

[0073] Mass spectrometry test value: 1109.39;

[0074] HPLC: ≥99.3%;

[0075] 1 H NMR (400 MHz, deuterated chloroform) δ 8.39 – 8.35 (m, 1H), 8.00 – 7.89 (m,3H), 7.66 (ddd, 1H), 7.55 (d, 1H), 7.50 (t, 1H), 7.22 (d, 1H), 2.24 (d, 3H).

[0076] ;

[0077] Step 4: Under nitrogen atmosphere, add intermediate S8 (1eq), bipyraclostrobin (1.5eq), and potassium acetate (3eq) to 1,4-dioxane (100ml) solvent, replace nitrogen, add tris(dibenzylideneacetone)dipalladium (DBA palladium for short) (3%eq) under nitrogen protection, and heat to 100°C and reflux for 12 hours. When the reaction is complete, concentrate and dry, pass through a silica gel funnel, concentrate, and column chromatography to obtain intermediate S9 with a yield of 64.49%.

[0078] Mass spectrometry test value: 403.52;

[0079] HPLC: ≥99%.

[0080] ;

[0081] Step 5: Under a nitrogen atmosphere, 1-bromo-2,4,6-triphenylbenzene (1 eq), intermediate S9 (1.5 eq), and anhydrous potassium carbonate (3 eq) were added to the reaction system in sequence, dissolved in a mixed solution of tetrahydrofuran and water (volume ratio 3:1), and nitrogen was replaced twice. Under nitrogen protection, tri(dibenzylideneacetone)dipalladium (3% eq) was added to the phase system, and nitrogen was replaced twice. The system was heated to 75°C for reflux reaction for 10 hours, the heating was turned off, and the system was cooled to room temperature. The system was allowed to stand for separation, and the aqueous phase was extracted twice with ethyl acetate. The organic phases were combined, washed three times with water, spin-dried, and subjected to column chromatography to obtain intermediate S10 with a yield of 48.24%.

[0082] Mass spectrometry test value: 581.45;

[0083] HPLC: ≥99.6%.

[0084] ;

[0085] Step 6: Under nitrogen protection, weigh A-497 (2.2 eq) and IrC13•3H2O (1 eq) into the reaction system, dissolve in a mixed solution of ethylene glycol ethyl ether and water (volume ratio 3:1), reflux for 48 hours under nitrogen protection, then cool to room temperature, and precipitate is precipitated. Filter the precipitate, rinse and dry it with water, anhydrous ethanol and petroleum ether in turn to obtain the bridging ligand B-497 with a yield of 94.02%.

[0086] Step 7: Weigh the bridging ligand B-497 (1 eq), add silver trifluoromethanesulfonate (2.2 eq), dissolve in a mixed solution of dichloromethane and methanol (volume ratio 3:1), react at room temperature for 48 hours under nitrogen protection, pass through a silica gel funnel, and spin dry to obtain intermediate C-497 with a yield of 95.12%.

[0087] Step 8: Weigh the intermediate C-497 (1 eq), add the ligand S10 (2.5 eq), dissolve in anhydrous ethanol, reflux for 48 hours under nitrogen protection, filter, wash with alcohol, and dry; use a mixture of petroleum ether and dichloromethane as eluent, column chromatography, concentrate the filtrate and precipitate the solid to obtain the organic electroluminescent material G-695, yield: 37.38%.

[0088] Mass spectrometry test value: 1109.39;

[0089] HPLC: ≥99.3%;

[0090] G-695 H NMR spectrum is attached Figure 1 .

[0091] Theoretical value of elemental analysis: C, 71.46%; H, 4.27%; F, 1.71%; N, 3.79%; O, 1.44%; tested value: C, 71.49%; H, 4.26%; F, 1.70%; N, 3.75%; O, 1.46%.

[0092] The synthesis methods of other organic electroluminescent materials G-2, G-9, G-107, G-137, G-241, G-280, G-322, G-329, G-503, G-618, G-734, G-751, G-800, G-899, G-909, G-910, G-916, G-923, G-970 and G-1010 are the same as those in the above embodiments, and are not described one by one here. The molecular formula and mass spectrum of other synthesized organic electroluminescent materials are shown in Table 1:

[0093] Table 1 Molecular formula and mass spectrum of organic electroluminescent materials

[0094]

[0095] Device Example 1: Fabrication of an organic electroluminescent device containing an organic electroluminescent material of Formula I

[0096] The ITO glass substrate with a coating thickness of 150nm was cleaned twice in distilled water and ultrasonically washed for 30 minutes, and then repeatedly cleaned twice with distilled water and ultrasonically washed for 10 minutes. After the distilled water cleaning, ultrasonically washed with isopropyl alcohol, acetone, methanol and other solvents in sequence, and then dried and transferred to a plasma cleaning machine. The above substrate was washed for 5 minutes and sent to a vapor deposition machine.

[0097] First, 60nm of HAT is vacuum evaporated on ITO (anode) as a hole injection layer; then 60nm of BPD is vacuum evaporated on the hole injection layer as a hole transport layer; a light-emitting layer is vacuum evaporated on the hole transport layer, wherein the main material CBP of the light-emitting layer and the doping material compound I are mixed and evaporated at a weight ratio of 95:5 to form a light-emitting layer; then 10nm thick BAlq is vacuum evaporated to form a hole blocking layer; then 40nm thick Alq3 is vacuum evaporated on the hole blocking layer to form an electron transport layer; then 0.2nm thick LiF is vacuum evaporated on it as an electron injection layer; and 150nm thick Al is vacuum evaporated on the electron injection layer as a cathode. An electroluminescent device is prepared in this way.

[0098] Under the condition of certain brightness, the performance and luminescence characteristics of the obtained electroluminescent device are tested to evaluate the driving voltage, maximum external quantum efficiency and phosphorescence lifetime.

[0099] In the present invention, the material structure used in the organic electroluminescent device is as follows:

[0100] .

[0101] Device Comparison Example:

[0102] An organic electroluminescent device was prepared in the same manner as in Device Example 1, except that the doping material of the light-emitting layer was replaced with Compound 1, Compound 2, Compound 3, and Compound 4, and the structure thereof was as follows:

[0103] ,

[0104] The prepared organic electroluminescent device was subjected to the same tests as those in device example 1. The results are shown in Table 2.

[0105] Table 2 Test results of organic electroluminescent devices

[0106]

[0107] It can be seen from Table 2 that:

[0108] 1) By changing the degree of conjugation of the heterocyclic ligand, the organic electroluminescent material prepared by the present invention is compared with the comparative compound. After being used in an organic electroluminescent device, the driving voltage of the organic electroluminescent material prepared by the present invention is significantly reduced, the maximum external quantum efficiency is improved, and the life span is significantly improved.

[0109] 2) By introducing functional groups at different positions of the ligand, the conjugation effect is enhanced, so that after the organic electroluminescent materials G-597 and G-695 prepared by the present invention are used in organic electroluminescent devices, it is tested that the driving voltage of the device is significantly reduced, the maximum external quantum efficiency is improved, and the life span is significantly improved.

[0110] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organic electroluminescent material, characterized in that: The organic electroluminescent material has a structure shown in formula a to formula d: ； Among them, R1, R2, R3, R4, R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 and R 18 Each is independently selected from hydrogen, deuterium, cyano, -CD3, -CD2CD3, -(CD3)3, -F, methyl, ethyl, propyl, butyl, pentyl, cyclopropyl, cyclobutyl, cyclopentyl, methoxy, ethoxy, phenyl, naphthyl or the following groups: ； At least one of R5, R6, R7 and R8 is not hydrogen, and each is independently selected from hydrogen, deuterium, -F, -CN, -CD3, -CD2CD3, -(CD3)3, methyl, ethyl, propyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, neopentyl, cyclopentyl, cyclohexyl, phenyl, biphenyl, naphthyl or the following groups: ； R9 and R 10 Each is independently selected from hydrogen, deuterium, fluorine, cyano, -CD3, methyl, ethyl, propyl, isobutyl, tert-butyl, isopentyl, cyclopentyl, and cyclohexyl.

2. The organic electroluminescent material according to claim 1, characterized in that: LA ligand Select from the following structures: 。 3. The organic electroluminescent material according to claim 1 or 2, characterized in that: LB ligand Select from the following structures: .

4. The organic electroluminescent material according to claim 1, characterized in that: The organic electroluminescent material is selected from any one of the following structures: 。 5. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises the organic electroluminescent material according to claim 1.

6. The organic electroluminescent device according to claim 5, characterized in that: The organic electroluminescent device comprises an anode, a cathode and an organic layer disposed between the anode and the cathode; the organic layer contains the organic electroluminescent material.

7. The organic electroluminescent device according to claim 6, characterized in that: The organic electroluminescent device comprises a light-emitting layer, and the light-emitting layer comprises the organic electroluminescent material.

8. The organic electroluminescent device according to claim 7, characterized in that: The light-emitting layer of the organic electroluminescent device comprises a main material and a doping material; the doping material is the organic electroluminescent material, and the mixing mass ratio of the main material to the doping material is 90:10-99.5:0.5.

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