Organic electroluminescent material, preparation method therefor, and use thereof

Abstract

The present invention belongs to the field of organic photoelectric materials. Disclosed are an organic electroluminescent material, a preparation method therefor, and use thereof. The structure of the organic electroluminescent material is as shown in formula I. The compound provided by the present invention can be used as a doping material for a luminescent layer. By selecting a specific ligand compound and substituting with a specific substituent at the 3-position of dibenzothiophene, the spatial configuration and three-dimensional structure between molecules can be changed, resulting in a designed molecular orientation. The present invention features superior device performance of higher turn-on voltage and low driving voltage, and it mitigates the crosstalk between sub-pixels and endows OLED devices with the advantages of long service life, high efficiency, and low driving voltage.

Description

An organic electroluminescent material, its preparation method and application

[0001] This disclosure claims priority to the prior application filed by the applicant with the China National Intellectual Property Administration on October 17, 2024, with patent application number 2024114496951 entitled "An organic electroluminescent material and its preparation method and application"; the full text of the prior application is incorporated herein by reference. Technical Field

[0002] This invention belongs to the field of organic optoelectronic materials, specifically relating to an organic electroluminescent material, its preparation method, and its application. Background Technology

[0003] Organic light-emitting displays (OLEDs) are active-emitting display devices with advantages such as simple manufacturing process, low cost, high contrast, wide viewing angle, and low power consumption. Optoelectronic devices using organic materials are becoming increasingly popular.

[0004] The performance of materials used to fabricate OLED display devices affects the display's performance. Generally, organic photoluminescent materials need to have the following performance requirements: 1. High luminous efficiency; 2. Excellent electron and hole stability; 3. Suitable emission color; 4. Low driving voltage; 5. Suitable turn-on voltage; 6. Excellent film-forming processability.

[0005] In existing OLED display devices, the turn-on voltages of the RGB sub-pixels are not consistent. Turn-on voltage is defined as the voltage required to achieve a device luminance of 1 cd / m². A low turn-on voltage can lead to crosstalk between sub-pixels at low grayscale levels. Meanwhile, achieving optimal luminous efficiency under low driving voltage conditions is a common requirement in the OLED field; reducing the driving voltage is an important way to reduce power consumption and improve device luminous efficiency and stability.

[0006] Therefore, how to obtain organic electroluminescent materials with high turn-on voltage and low driving voltage is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the technical problem to be solved by the present invention is to provide an organic electroluminescent material with a high turn-on voltage and a low driving voltage, thereby obtaining an organic electroluminescent device with high efficiency and long life.

[0008] To achieve the above objectives, the first objective of this invention is to provide an organic electroluminescent material. The following technical solution is adopted:

[0009] An organic electroluminescent material has the molecular formula Ir(LA)2(LB) and has the structure of formula I:

[0010] In the general formula, R is selected from any one of -D (deuterium), -T (tritium), -F, -CN, -CT3, -CF3, -CH2F, -CHF2, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted 4-24 membered aromatic heterocyclic groups;

[0011] R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 R 11 It is independently selected from any one of -H, -D (deuterium), -T (tritium), -F, -CN, -CD3, -CT3, -CF3, -CH2F, -CHF2, -Ge(Me)3, -Si(Me)3, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted 4-24 membered aromatic heterocyclic groups.

[0012] It should be noted that the organic electroluminescent device provided by the present invention uses doped materials with specific atomic structures. By introducing substituents at the 3-position of dibenzothiophene, the spatial stereochemistry and size of the obtained compound molecular structure are adjusted, so that the obtained organic compound, when used in organic electroluminescent devices, has long lifespan, high efficiency, low driving voltage, and can also improve the turn-on voltage.

[0013] Furthermore, all atoms in the above groups can be replaced by deuterium.

[0014] Further, R is selected from -D, -F, -CN, -CF3, -CH2F, -CHF2, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, biphenyl, fluorenyl, phenanthrene, triphenylene, furanyl, benzofuranyl, benzothiophene, dibenzofuranyl, dibenzothiophene, or any of the following substituents:

[0015] R1-R 11Independently selected from -H, -D (deuterium), -T (tritium), -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -Ge(Me)3, -Si(Me)3, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, thiacyclopentane, phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, Any one of phenanthrene, anthracene, indene, triphenylene, fluoranthracene, furanyl, thiophene, imidazolyl, pyrazolyl, thiazolyl, pyridinyl, pyrazinyl, pyrimidinyl, benzofuranyl, benzothiophene, isobenzofuranyl, dibenzofuranyl, dibenzothiophene, benzimidazolyl, benzothiazolyl, benziisothiazolyl, benzothiadiazolyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, and carbazoleyl.

[0016] Furthermore, R is selected from methyl, ethyl, -F, -CN, -CF3, or any of the following substituents:

[0017] R1 is hydrogen, methyl, ethyl, -F, -CN, -CF3, or any of the following substituents:

[0018] R2 and R3 are independently selected from -H or -D.

[0019] It is worth noting that in this invention, * represents a connection position; "substitution" means that it can be replaced by -H, -D (deuterium), -T (tritium), -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -Ge(Me)3, -Si(Me)3, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, thiacyclopentane, phenyl, Substitution with groups such as biphenyl, triphenyl, naphthyl, fluorenyl, phenanthryl, anthracene, indyl, triphenylene, fluoranthracene, furanyl, thiophene, imidazolyl, pyrazolyl, thiazolyl, pyridinyl, pyrazinyl, pyrimidinyl, benzofuranyl, benzothiophene, isobenzofuranyl, dibenzofuranyl, dibenzothiophene, benzimidazolyl, benzothiazolyl, benziisothiazolyl, benzothiadiazolyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazole, etc.

[0020] Furthermore, the organic electroluminescent material is selected from one of the following structures:

[0021] The second objective of this invention is to provide a method for preparing the organic electroluminescent material as described above, the specific operation of which is as follows:

[0022] 1. Under nitrogen protection, the ligand LA structure compound and IrCl3·3H2O were placed in the reaction system, and a mixed solution of ethylene glycol ethyl ether and pure water was added. The reaction was refluxed under nitrogen protection and then cooled to room temperature. A precipitate was formed. The precipitate was filtered, washed with water, anhydrous ethanol and petroleum ether in sequence and dried to obtain the bridged ligand compound shown in intermediate formula II.

[0023] 2. Weigh the intermediate compound of formula II and anhydrous potassium carbonate, add ethylene glycol ethyl ether, then add the compound of ligand formula LB structure, reflux under nitrogen protection, filter, wash with alcohol, and dry; use dichloromethane as solvent, perform silica gel column chromatography, concentrate the filtrate to precipitate the solid, and obtain the compound shown in formula I;

[0024] The specific synthetic route is as follows:

[0025] Where R, R1-R 11 The groups represented are the same as those mentioned above.

[0026] The third objective of this invention is to provide an application of an organic electroluminescent material, as described above, which can be used as a dopant material in an organic electroluminescent device.

[0027] Compared with the prior art, the present invention provides an organic electroluminescent material, its preparation method and application, which has the following superior effects:

[0028] 1. By introducing substituent groups at the 3-position of dibenzothiophene, the spatial structure size and morphology of the resulting material can be adjusted, resulting in special device performance with improved turn-on voltage and low driving voltage. This also improves crosstalk between sub-pixels and gives OLED devices the advantages of long lifespan, high efficiency, and low driving voltage.

[0029] 2. In the study of the diketone ligand portion of iridium complexes, a complete theoretical framework has not yet been established. Because the carbon atoms on the side chains do not participate in conjugation, they have some influence on the electron cloud distribution, but the impact is not significant. Studies have also found that the length, configuration, and group size of the side chain alkyl groups all have a certain degree of influence on the wavelength, full width at half maximum (FWHM), efficiency, lifetime, and CIE coordinates of the doped material. More importantly, for different red light host (RH) materials, controlling the molecular structure of the diketone ligand to achieve a match between RH and red light doped materials (RD) is currently largely without directional guidance and requires verification through extensive experiments.

[0030] In summary, the light-emitting layer of the organic electroluminescent device adopts the doped material shown in Formula I of this invention and the structure formed with the host material, and in combination with other layer materials, which can effectively improve the start-up voltage, maintain a low driving voltage, improve crosstalk between sub-pixels, improve efficiency, and improve the problem of low lifetime. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 shows the brightness-voltage test results of the organic electroluminescent devices prepared by compound I-3 and Comparative Example 5.

[0033] Figure 2 shows the 1H NMR spectrum of compound I-3. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and related drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] This invention specifically discloses an organic electroluminescent material, its preparation method, and its application.

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides an organometallic compound I-1, namely compound numbered I-1, and the specific synthesis steps are as follows:

[0039] Under nitrogen protection, 950 mmol of 1-bromo-2-chloro-4-iodo-3-methylbenzene (CAS: 1000573-57-8), 950 mmol of isobutylboronic acid (CAS: 84110-40-7), and 990 mmol of anhydrous potassium carbonate were weighed and added to the reaction system. 2000 mL of toluene, 1000 mL of anhydrous ethanol, and 1000 mL of purified water were added. 9.5 mmol of Pd(PPh3)4 was added under nitrogen protection. The mixture was refluxed at 100 °C for 25 h under nitrogen protection. After the reaction was complete, the mixture was separated, extracted with ethyl acetate, washed three times with saturated brine, and concentrated under reduced pressure. The solution was dissolved in 400 mL of dichloromethane. The solution was then subjected to column chromatography (200–300 mesh, 900 g) using DCM:PE as the developing solvent at a ratio of 1:2. The receiving liquid was vortexed until no liquid flowed out, yielding the compound of formula L. AE -1 (93.8 g, yield 37.9%), the intermediate compound of formula L AE -1 Perform the following analysis and tests:

[0040] HPLC purity: greater than 99.5%;

[0041] Mass spectrometry: The measured value is 260.12.

[0042] Under nitrogen protection, compound L was added sequentially. AE -1 (360 mmol), pinacol diboronate (360 mmol), X-Phos (72 mmol), palladium acetate (7.2 mmol), potassium acetate (1080 mmol), and dioxane (1200 mL) were added to the reaction system. The mixture was substituted three times with N2 under N2 protection and heated at 100 °C with stirring overnight. After the reaction was complete, the mixture was filtered through diatomaceous earth and anhydrous magnesium sulfate, washed twice with ethyl acetate, and the organic phase was collected and concentrated under reduced pressure to obtain the crude intermediate of formula L. AD -1 is used directly in the next step.

[0043] Under nitrogen protection, compound L was added sequentially. AD -1 (360 mmol), cuprous bromide (360 mmol), and anhydrous sodium methanethiol (1080 mmol) were added to DMF (900 mL), followed by water (90 mL). The mixture was substituted three times with N2 under N2 protection and heated and stirred at 140 °C for 48 h. After the reaction was complete, the mixture was cooled to room temperature, and the reaction solution was poured into three times its volume of water. A solid precipitated, which was filtered. The solid was dissolved in DCM, and the filtrate was passed through a silica gel funnel, washed with DCM, and evaporated to dryness to give the crude intermediate of formula L. AC -1 is used directly in the next reaction.

[0044] Under nitrogen protection, weigh out the compound of formula L AC -1 (360 mmol), 2-chloro-3-amino-4-bromopyridine (CAS: 1354021-09-2) (360 mmol), and anhydrous potassium carbonate (1080 mmol) were added to the reaction system. 2600 mL of toluene, 1300 mL of anhydrous ethanol, and 1300 mL of purified water were added. Pd(PPh3)4 (7.2 mmol) was added under nitrogen protection. The mixture was refluxed at 100 °C for 26 h under nitrogen protection. After the reaction was complete, the mixture was separated, extracted with ethyl acetate, washed three times with saturated brine, and concentrated under reduced pressure. 400 mL of dichloromethane was added to dissolve the solution. The solution was then subjected to column chromatography (200–300 mesh, 1000 g) using DCM:PE = 1:1 as the developing solvent. The receiving liquid was vortexed until no liquid flowed out, yielding the compound of formula L. AB -1 (55.3 g, yield 48.2%), the intermediate compound L AB -1 Perform the following analysis and tests:

[0045] HPLC purity: greater than 99.5%;

[0046] Mass spectrometry: The measured value is 320.26.

[0047] Under nitrogen protection, weigh out the compound of formula L AB -1 (170 mmol) was dissolved in THF (700 mL) in the reaction system. The temperature was raised to 55℃~57℃, and then heating was stopped. Copper acetate (170 mmol) was added, followed by 90 mL of THF solution containing tert-butyl nitrite (204 mmol) which was carefully added dropwise to the system. The system exhibited exothermic and gas-releasing behavior. After the addition was complete, the system was kept at this temperature for 1.5 h to complete the reaction. The reaction solution was directly concentrated to dryness under reduced pressure, and then dissolved under reflux in DCM (900 mL) until clear. The solution was passed through a silica gel column, and the column liquid was collected and concentrated under reduced pressure to a remaining volume of about 100 mL, after which a solid precipitated. The solution was cooled to below 20℃, filtered, dried under vacuum, and then dried to obtain compound L. AA -1 (22.1 g, yield 45.1%), the intermediate compound L AA -1 Perform the following analysis and tests:

[0048] HPLC purity: greater than 99.5%;

[0049] The mass spectrometry value was 289.42.

[0050] Under nitrogen protection, weigh out the compound of formula L AA-1 (75 mmol), [4-(tert-butyl)naphthyl]-2-boronic acid pinacol ester (CAS: 2217657-10-6) (82.5 mmol), and anhydrous potassium carbonate (225 mmol) were added to the reaction system. 1200 mL of toluene, 600 mL of anhydrous ethanol, and 600 mL of purified water were added. Pd(PPh3)4 (1.5 mmol) was added under nitrogen protection. The mixture was refluxed at 100 °C for 24 h under nitrogen protection. After the reaction was complete, the mixture was separated, extracted with ethyl acetate, washed three times with saturated brine, and concentrated under reduced pressure. 200 mL of dichloromethane was added to dissolve the solution. The solution was then subjected to column chromatography (200–300 mesh, 600 g) with DCM:PE = 1:5 as the developing solvent. The receiving liquid was vortexed until no liquid flowed out, yielding the compound of formula L. A -1 (22.3 g, yield 68.1%), the intermediate compound L A -1 Perform the following analysis and tests:

[0051] HPLC purity: greater than 99.5%;

[0052] Mass spectrometry: The measured value was 437.39;

[0053] Elemental analysis:

[0054] The calculated values ​​are C, 82.33; H, 7.14; N, 3.20; S, 7.33.

[0055] The test values ​​were C, 82.35; H, 7.12; N, 3.21; S, 7.32.

[0056] Under nitrogen protection, weigh the ligand of type L A -1 (48.4 mmol) and IrCl3·3H2O (22 mmol) were added to the reaction system, along with a mixed solution of 450 mL ethylene glycol ethyl ether and 150 mL purified water. The mixture was refluxed under nitrogen protection for 28 hours, then cooled to room temperature. A precipitate was formed. The precipitate was filtered, washed with water, anhydrous ethanol, and petroleum ether in sequence, and dried to obtain a dark red powder of bridged ligand II-1 (14.52, yield 59.8%).

[0057] Weigh out 5.5 mmol of the bridging ligand II-1, add 55 mmol of anhydrous potassium carbonate, then add 190 ml of ethylene glycol ethyl ether to the system, purge with nitrogen three times, and add formula L under nitrogen atmosphere. BThe compound (CAS: 2891969-73-4) (16.5 mmol) was refluxed for 23 hours under nitrogen protection, cooled, filtered, washed with alcohol, and dried. The mixture was then subjected to neutral alumina column chromatography using dichloromethane as solvent. The filtrate was concentrated to precipitate the solid, ultimately yielding the luminescent material shown in I-1 (4.3 g, yield 29.4%).

[0058] The organometallic compound I-1 was subjected to the following analytical tests:

[0059] HPLC purity: greater than 99.5%;

[0060] Mass spectrometry: The measured value was 1332.75;

[0061] Elemental analysis:

[0062] The calculated values ​​are C, 69.38; H, 6.88; N, 2.10; O, 2.40; S, 4.81.

[0063] The test values ​​were: C, 69.39; H, 6.87; N, 2.11; O, 2.41; S, 4.80.

[0064] 1 H NMR(400MHz,Chloroform-d)δ8.87(d,2H),8.34(dd,2H),7.98(dd,2H),7.81(d,2H),7.71(d,2H),7.62(s,2H),7.45(td,2H),7.37(td,2H),7.27(d,2 H),5.68(dd,1H),2.78(pd,1H),2.60-2.51(m,5H),2.29(s,6H),1.90(dp, 2H),1.74(dq,2H),1.62-1.39(m,26H),0.93-0.84(m,18H),0.83(dd,12H).

[0065] Example 2

[0066] This embodiment provides an organometallic compound I-3, namely compound numbered I-3, and the specific synthesis steps are as follows:

[0067] Under nitrogen protection, 1380 mmol of 1-bromo-2-chloro-4-iodo-3-methylbenzene (CAS: 1000573-57-8), 1380 mmol of neopentylboronic acid (CAS: 701261-35-0), and 4140 mmol of anhydrous potassium carbonate were weighed and added to the reaction system. 2500 mL of toluene, 1250 mL of anhydrous ethanol, and 1250 mL of purified water were added. 27.6 mmol of Pd(PPh3)4 was added under nitrogen protection. The mixture was refluxed at 100 °C for 25 h under nitrogen protection. After the reaction was complete, the mixture was separated, extracted with ethyl acetate, washed three times with saturated brine, and concentrated under reduced pressure. The solution was dissolved in 600 mL of dichloromethane. The solution was then subjected to column chromatography (200–300 mesh, 1000 g) using DCM:PE = 1:4 as the developing solvent. The receiving liquid was vortexed until no liquid flowed out, yielding the compound of formula L. AE -3 (121.0 g, yield 32.1%), the intermediate compound of formula L AE -3. Perform the following analysis and tests:

[0068] HPLC purity: greater than 99.5%;

[0069] Mass spectrometry: The measured value is 274.15.

[0070] Under nitrogen protection, compound L was added sequentially. AE -3 (440 mmol), pinacol diboronate (440 mmol), X-Phos (88 mmol), palladium acetate (8.8 mmol), potassium acetate (1320 mmol), and dioxane (2000 mL) were added to the reaction system. The mixture was subjected to three N2 displacements under N2 protection and heated at 100 °C with stirring overnight. After the reaction was complete, the mixture was filtered through diatomaceous earth and anhydrous magnesium sulfate, washed twice with ethyl acetate, and the organic phase was collected and concentrated under reduced pressure to obtain the crude intermediate of formula L. AD -3 is used directly in the next step.

[0071] Under nitrogen protection, compound L was added sequentially. AD -3 (440 mmol), cuprous bromide (440 mmol), and anhydrous sodium methanethiol (1320 mmol) were added to DMF (1500 mL), followed by water (150 mL). The mixture was substituted three times with N2 under N2 protection and heated and stirred at 140 °C for 45 h. After the reaction was complete, the mixture was cooled to room temperature, and the reaction solution was poured into three times its volume of water. A solid precipitated, which was filtered. The solid was dissolved in DCM, and the filtrate was passed through a silica gel funnel, washed with DCM, and evaporated to dryness to give the crude intermediate of formula L. AC -3 is used directly in the next reaction.

[0072] Under nitrogen protection, weigh out the compound of formula L AC -3 (440 mmol), 2-chloro-3-amino-4-bromopyridine (CAS: 1354021-09-2) (440 mmol), and anhydrous potassium carbonate (1320 mmol) were added to the reaction system. 2800 mL of toluene, 1400 mL of anhydrous ethanol, and 1400 mL of purified water were added. Pd(PPh3)4 (8.8 mmol) was added under nitrogen protection. The mixture was refluxed at 100 °C for 22 h under nitrogen protection. After the reaction was complete, the mixture was separated, extracted with ethyl acetate, washed three times with saturated brine, and concentrated under reduced pressure. 700 mL of dichloromethane was added to dissolve the solution. The solution was then subjected to column chromatography (200–300 mesh, 1200 g) using DCM:PE = 1:2 as the developing solvent. The receiving liquid was vortexed until no liquid flowed out, yielding the compound of formula L. AB -3 (72.1 g, yield 49.3%), the intermediate compound of formula L AB -3. Perform the following analysis and tests:

[0073] HPLC purity: greater than 99.5%;

[0074] Mass spectrometry: The measured value is 334.28.

[0075] Under nitrogen protection, weigh out the compound of formula L AB -3 (215 mmol) was dissolved in THF (800 mL) in the reaction system. The temperature was raised to 55℃~57℃, and then heating was stopped. Copper acetate (215 mmol) was added, followed by 120 mL of THF solution containing tert-butyl nitrite (258 mmol) which was carefully added dropwise to the system. The system exhibited exothermic and gas-releasing behavior. After the addition was complete, the system was kept at this temperature for 1.5 h to complete the reaction. The reaction solution was directly concentrated to dryness under reduced pressure, and then dissolved under reflux in DCM (1000 mL) until clear. The solution was passed through a silica gel column, and the column liquid was collected and concentrated under reduced pressure to approximately 100 mL. A solid precipitated out. The solution was cooled to below 20℃, filtered, dried under vacuum, and then dried to obtain compound L. AA -3 (27.4 g, yield 42.3%), the intermediate compound of formula L AA -3. Perform the following analysis and tests:

[0076] HPLC purity: greater than 99.5%;

[0077] The mass spectrometry value was 303.26.

[0078] Under nitrogen protection, weigh out the compound of formula L AA-3 (90 mmol), [4-(tert-butyl)naphthalene]-2-boronic acid pinacol ester (CAS: 2217657-10-6) (99 mmol), and anhydrous potassium carbonate (270 mmol) were added to the reaction system. 1500 mL of toluene, 750 mL of anhydrous ethanol, and 750 mL of purified water were added. Pd(PPh3)4 (1.8 mmol) was added under nitrogen protection. The mixture was refluxed at 100 °C for 20 h under nitrogen protection. After the reaction was complete, the mixture was separated, extracted with ethyl acetate, washed three times with saturated brine, and concentrated under reduced pressure. 200 mL of dichloromethane was added to dissolve the solution. The solution was then subjected to column chromatography (200-300 mesh, 700 g) using DCM:PE = 1:4 as the developing solvent. The receiving liquid was vortexed until no liquid flowed out, yielding the compound of formula L. A -3 (23.2 g, yield 57.3%), the intermediate compound of formula L A -3. Perform the following analysis and tests:

[0079] HPLC purity: greater than 99.5%;

[0080] Mass spectrometry: The measured value was 451.37;

[0081] Elemental analysis:

[0082] The calculated values ​​are C, 82.44; H, 7.36; N, 3.10; S, 7.10.

[0083] The test values ​​were C, 82.46; H, 7.32; N, 3.11; S, 7.11.

[0084] Under nitrogen protection, weigh the ligand of type L A -3 (50 mmol) and IrCl3·3H2O (22 mmol) were added to the reaction system, along with a mixed solution of 480 mL ethylene glycol ethyl ether and 160 mL purified water. The mixture was refluxed under nitrogen protection for 30 hours, then cooled to room temperature. A precipitate was formed. The precipitate was filtered, washed with water, anhydrous ethanol, and petroleum ether in sequence, and dried to obtain a dark red powder of bridged ligand II-3 (14.2, yield 57.4%).

[0085] Weigh out the bridging ligand II-3 (5.5 mmol), add anhydrous potassium carbonate (55 mmol), then add 200 ml of ethylene glycol ethyl ether to the system, purge with nitrogen three times, and add formula L under nitrogen atmosphere. B The compound (CAS: 2891969-73-4) (22 mmol) was refluxed for 23 hours under nitrogen protection, cooled, filtered, washed with alcohol, and dried. The mixture was then subjected to neutral alumina column chromatography using dichloromethane as solvent. The filtrate was concentrated to precipitate the solid, ultimately yielding the luminescent material shown in I-3 (5.1 g, yield 34.1%).

[0086] The organometallic compound I-3 was subjected to the following analytical tests:

[0087] HPLC purity: greater than 99.5%;

[0088] Mass spectrometry: The measured value was 1360.87;

[0089] Elemental analysis:

[0090] The calculated values ​​are C, 69.72; H, 7.04; N, 2.06; O, 2.35; S, 4.71.

[0091] The test values ​​were C, 69.74; H, 7.02; N, 2.06; O, 2.32; S, 4.74.

[0092] Figure 2 shows the proton NMR spectrum of compound I-3.

[0093] Example 3

[0094] This embodiment provides an organometallic compound I-70, namely the compound numbered I-70, and the specific synthesis steps are as follows:

[0095] Where, formula L AA The preparation method of -70 is as shown in Example 2, formula L A As shown in -1, no further details will be provided.

[0096] Under nitrogen protection, weigh out the compound of formula L AA -70 (100 mmol), deuterated benzene (10000 mmol), and trifluoromethanesulfonic acid (300 mmol) were added to the reaction system, and the mixture was refluxed under nitrogen protection for 18 h. After the reaction was complete, the mixture was quenched with heavy water, extracted with ethyl acetate, washed three times with saturated brine, concentrated under reduced pressure, and column-chromatographically analyzed (200-300 mesh, 600 g) with DCM:PE = 1:10 as the developing solvent. The receiving liquid was vortexed until no liquid flowed out, yielding the compound of formula L shown. A -70 (23.9 g, yield 51.9%), intermediate compound L A -70 underwent the following analysis and testing:

[0097] HPLC purity: greater than 99.5%;

[0098] Mass spectrometry: The measured value was 460.43;

[0099] Elemental analysis:

[0100] The calculated values ​​are C, 80.82; H, 9.19; N, 3.04; S, 6.96.

[0101] The test values ​​were C, 80.84; H, 9.17; N, 3.06; S, 6.94.

[0102] Under nitrogen protection, weigh the ligand of type L A -70 (55 mmol) and IrCl3·3H2O (22 mmol) were added to the reaction system, along with a mixed solution of 540 mL of ethylene glycol ethyl ether and 180 mL of purified water. The mixture was refluxed under nitrogen protection for 32 hours, and then cooled to room temperature. A precipitate was formed. The precipitate was filtered, washed with water, anhydrous ethanol, and petroleum ether in sequence, and dried to obtain a dark red powder of bridging ligand II-70 (14.80 g, yield 58%).

[0103] Weigh out the bridging ligand II-70 (5.5 mmol), add anhydrous potassium carbonate (55 mmol), then add 190 ml of ethylene glycol ethyl ether to the system, purge with nitrogen three times, and add formula L under nitrogen atmosphere. B The compound (CAS: 2891969-73-4) (11 mmol) was refluxed for 36 hours under nitrogen protection, cooled, filtered, washed with alcohol, and dried. The mixture was then subjected to neutral alumina column chromatography using dichloromethane as solvent. The filtrate was concentrated to precipitate the solid, ultimately yielding the luminescent material shown in I-70 (4.7 g, yield 31.2%).

[0104] The organometallic compound I-70 was subjected to the following analytical tests:

[0105] HPLC purity: greater than 99.5%;

[0106] Mass spectrometry: The measured value was 1378.95;

[0107] Elemental analysis:

[0108] The calculated values ​​are: C, 68.80; H, 8.26; N, 2.03; O, 2.32; S, 4.65.

[0109] The test values ​​were C, 68.82; H, 8.24; N, 2.03; O, 2.35; S, 4.62.

[0110] 1 H NMR(400MHz,Chloroform-d)δ5.60(dd,1H),2.78(d,1H),2.66-2.51(m,5H),2.32( s,6H),1.74(dq,2H),1.62-1.37(m,26H),1.03-0.99(m,18H),0.93-0.86(m,18H).

[0111] Example 4

[0112] This embodiment provides an organometallic compound I-99, namely compound numbered I-99, and the specific synthesis steps are as follows:

[0113] Under nitrogen protection, 1500 mmol of 2-bromo-1-chloro-4-iodobenzene (CAS: 31928-46-8), 1500 mmol of neopentylboronic acid (CAS: 701261-35-0), and 4500 mmol of anhydrous potassium carbonate were weighed and added to the reaction system. 3000 mL of toluene, 1500 mL of anhydrous ethanol, and 1500 mL of purified water were added. 30 mmol of Pd(PPh3)4 was added under nitrogen protection. The mixture was refluxed at 100 °C for 25 h under nitrogen protection. After the reaction was complete, the mixture was separated, extracted with ethyl acetate, washed three times with saturated brine, and concentrated under reduced pressure. The solution was dissolved in 900 mL of dichloromethane. The solution was then subjected to column chromatography (200–300 mesh, 1250 g) using DCM:PE = 1:6 as the developing solvent. The receiving liquid was vortexed until no liquid flowed out, yielding the compound of formula L. AE -99 (128.70 g, yield 33%), intermediate compound L AE -99 underwent the following analysis and testing:

[0114] HPLC purity: greater than 99.5%;

[0115] Mass spectrometry: The measured value is 260.17.

[0116] Under nitrogen protection, compound L was added sequentially. AE -99 (490 mmol), cuprous bromide (490 mmol), and anhydrous sodium methanethiol (1470 mmol) were added to DMF (1300 mL), followed by water (130 mL). The mixture was substituted three times with N2 under N2 protection and heated and stirred at 140 °C for 45 h. After the reaction was complete, the mixture was cooled to room temperature, and the reaction solution was poured into three times its volume of water. A solid precipitated, which was filtered. The solid was dissolved in DCM, and the filtrate was passed through a silica gel funnel, washed with DCM, and evaporated to dryness to give the crude intermediate of formula L. AD -99 is used directly in the next reaction.

[0117] Under nitrogen protection, compound L was added sequentially. AD-99 (490 mmol), pinacol diboronate (490 mmol), X-Phos (98 mmol), palladium acetate (9.8 mmol), potassium acetate (1470 mmol), and dioxane (1500 mL) were added to the reaction system. The mixture was subjected to three N2 displacements under N2 protection and heated at 100 °C with stirring overnight. After the reaction was complete, the mixture was filtered through diatomaceous earth and anhydrous magnesium sulfate, washed twice with ethyl acetate, and the organic phase was collected and concentrated under reduced pressure to obtain the crude intermediate of formula L. AC -99 is used directly for the next step.

[0118] Under nitrogen protection, weigh out the compound of formula L AC -99 (490 mmol), 2-chloro-3-amino-4-bromopyridine (CAS: 1354021-09-2) (490 mmol), and anhydrous potassium carbonate (1470 mmol) were added to the reaction system. 2900 mL of toluene, 1450 mL of anhydrous ethanol, and 1450 mL of purified water were added. Pd(PPh3)4 (9.8 mmol) was added under nitrogen protection. The mixture was refluxed at 100 °C for 28 h under nitrogen protection. After the reaction was complete, the mixture was separated, extracted with ethyl acetate, washed three times with saturated brine, and concentrated under reduced pressure. 400 mL of dichloromethane was added to dissolve the solution. The solution was then subjected to column chromatography (200–300 mesh, 1000 g) using DCM:PE = 1:1 as the developing solvent. The receiving liquid was vortexed until no liquid flowed out, yielding the compound of formula L. AB -99 (69.02 g, yield 44%), intermediate compound L AB -99 underwent the following analysis and testing:

[0119] HPLC purity: greater than 99.5%;

[0120] Mass spectrometry: The measured value is 320.26.

[0121] Under nitrogen protection, weigh out the compound of formula L AB -99 (215 mmol) was dissolved in THF (950 mL) in the reaction system. The temperature was raised to 55℃~57℃, and then heating was stopped. Copper acetate (215 mmol) was added, followed by 95 mL of THF solution containing tert-butyl nitrite (258 mmol) which was carefully added dropwise to the system. The system exhibited exothermic and gas-releasing behavior. After the addition was complete, the system was kept at this temperature for 2.5 h to complete the reaction. The reaction solution was directly concentrated to dryness under reduced pressure, and then dissolved under reflux in DCM (1000 mL) until clear. The solution was passed through a silica gel column, and the column liquid was collected and concentrated under reduced pressure to approximately 100 mL. A solid precipitated out. The solution was cooled to below 20℃, filtered, dried under vacuum, and then dried to obtain compound L. AA -99 (24.91 g, yield 40%), intermediate compound L AA-99 underwent the following analysis and testing:

[0122] HPLC purity: greater than 99.5%;

[0123] The mass spectrometry value was 289.26.

[0124] Under nitrogen protection, weigh out the compound of formula L AA -99 (85 mmol), [4-(tert-butyl)naphthalene]-2-boronic acid pinacol ester (CAS: 2217657-10-6) (102 mmol), and anhydrous potassium carbonate (255 mmol) were added to the reaction system. 1500 mL of toluene, 750 mL of anhydrous ethanol, and 750 mL of purified water were added. Pd(PPh3)4 (1.7 mmol) was added under nitrogen protection. The mixture was refluxed at 100 °C for 27 h under nitrogen protection. After the reaction was complete, the mixture was separated, extracted with ethyl acetate, washed three times with saturated brine, and concentrated under reduced pressure. 200 mL of dichloromethane was added to dissolve the solution. The solution was then subjected to column chromatography (200–300 mesh, 800 g) using DCM:PE = 1:5 as the developing solvent. The receiving liquid was vortexed until no liquid flowed out, yielding the compound of formula L. A -99 (22.3 g, yield 60.2%), the intermediate compound of formula L A -99 underwent the following analysis and testing:

[0125] HPLC purity: greater than 99.5%;

[0126] Mass spectrometry: The measured value was 437.37;

[0127] Elemental analysis:

[0128] The calculated values ​​are C, 82.33; H, 7.14; N, 3.20; S, 7.33.

[0129] The test values ​​were C, 82.35; H, 7.12; N, 3.22; S, 7.32.

[0130] Under nitrogen protection, weigh the ligand of type L A -99 (55 mmol) and IrC13·3H2O (22 mmol) were added to the reaction system, along with a mixed solution of 480 mL ethylene glycol ethyl ether and 160 mL purified water. The mixture was refluxed under nitrogen protection for 29 hours, then cooled to room temperature. A precipitate was formed. The precipitate was filtered, washed sequentially with water, anhydrous ethanol, and petroleum ether, and dried to obtain the bridged ligand II-99 (15.49 g, yield 64%).

[0131] Weigh out the bridging ligand II-99 (5.5 mmol), add anhydrous potassium carbonate (55 mmol), then add 230 ml of ethylene glycol ethyl ether to the system, purge with nitrogen three times, and add formula L under nitrogen atmosphere. B The compound (CAS: 2891969-73-4) (19.25 mmol) was refluxed for 26 hours under nitrogen protection, cooled, filtered, washed with alcohol, and dried. The solution was then subjected to neutral alumina column chromatography using dichloromethane as solvent. The filtrate was concentrated to precipitate the solid, ultimately yielding the luminescent material shown in I-99 (3.6 g, yield 25%).

[0132] The organometallic compound I-99 was subjected to the following analytical tests:

[0133] HPLC purity: greater than 99.5%;

[0134] Mass spectrometry: The measured value was 1332.74;

[0135] Elemental analysis:

[0136] The calculated values ​​are: C, 69.38; H, 6.88; N, 2.10; O, 2.40; S, 4.81.

[0137] The test values ​​were: C, 69.39; H, 6.87; N, 2.11; O, 2.41; S, 4.80.

[0138] 1 H NMR(400MHz,Chloroform-d)δ8.88(d,2H),8.34(dd,2H),7.98(dd,2H),7.89-7.84(m,4H),7.82(d,2H),7.57(s,2H),7.45(td,2H),7.37(td,2H), 7.23(dd,2H),5.68(dd,1H),2.78(pd,1H),2.55(pd,1H),2.48(s,4H),1. 74(dh,2H),1.61-1.39(m,26H),0.98-0.92(m,18H),0.92-0.86(m,18H).

[0139] The preparation methods for other compounds are the same as those described above, and will not be repeated here. The mass spectra or molecular formulas of other examples are shown in Table 1 below:

[0140] Table 1

[0141] The present invention also provides an organic electroluminescent device, wherein the organic electroluminescent device is made of the aforementioned organic electroluminescent material, more specifically, it is made of an organic electroluminescent material of a compound with chemical formula I.

[0142] Formula I of this invention is used as a doping material in the light-emitting layer, specifically as a phosphorescent doping material.

[0143] The present invention also provides a display panel comprising a substrate, a first electrode, a hole injection layer, a hole transport layer, an electron blocking layer, an organic electroluminescent layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a second electrode arranged sequentially.

[0144] Generally, an organic electroluminescent device includes a first electrode and a second electrode, as well as an organic material layer located between the electrodes. This organic material can be further divided into multiple regions. For example, the organic material layer may include a hole transport region, a light-emitting layer, and an electron transport region.

[0145] In specific embodiments, a substrate can be used below the first electrode or above the second electrode. The substrate is typically made of glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. Furthermore, thin-film transistors (TFTs) can also be incorporated into the substrate used for displays.

[0146] The first electrode can be formed by sputtering or depositing a material for use as the first electrode on a substrate. When the first electrode is used as the anode, it can be a transparent conductive oxide material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), or any combination thereof. Furthermore, the anode material can also be selected from materials and combinations thereof that facilitate hole injection, in addition to the anode materials listed above, including known materials suitable for use as anodes. When the first electrode is used as the cathode, it can be a metal or alloy such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), or any combination thereof. Besides the cathode materials listed above, the cathode material can also be a material and combination thereof that facilitates electron injection, including known materials suitable for use as cathodes.

[0147] The organic material layer can be formed on the electrode using methods such as vacuum thermal evaporation, spin coating, and printing. The compounds used as the organic material layer can be small organic molecules, large organic molecules, polymers, and combinations thereof. The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a monolayer hole transport layer (HTL), including monolayer hole transport layers containing only one compound and monolayer hole transport layers containing multiple compounds. The hole transport region can also be a multilayer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0148] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can be one or more compounds from HT-1 to HT-34 (as shown below), or one or more compounds from HI-1 to HI-3 described below; it can also be one or more compounds from HT-1 to HT-34 doped with one or more compounds from HI-1 to HI-3 described below, but is not limited to these materials.

[0149] The material of the hole transport layer may be selected from, but is not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives as shown in HT-1 to HT-34 below; or any combination thereof.

[0150] The emissive layer includes luminescent dyes (i.e., dopants) that can emit different wavelengths of light, and may also include a host material. The emissive layer can be a monochromatic emissive layer emitting a single color such as red, green, or blue. Multiple monochromatic emissive layers of different colors can be arranged in a planar pattern according to pixel design, or they can be stacked together to form a colored emissive layer. When different colored emissive layers are stacked together, they can be separated from each other or connected to each other. The emissive layer can also be a single-color emissive layer that can simultaneously emit different colors such as red and green.

[0151] Depending on the technology used, the light-emitting layer material can be phosphorescent photoluminescent material, thermally activated delayed fluorescence material, etc. In an OLED device, a single light-emitting technology can be used, or a combination of multiple different light-emitting technologies can be used. These different light-emitting materials, classified by technology, can emit light of the same color or different colors. Formula I of this invention is used as the doping material in the light-emitting layer.

[0152] The organic material layer of an OLED may also include an electron transport region between the light-emitting layer and the cathode. The electron transport region can be a single-layer electron transport layer (ETL), including single-layer electron transport layers containing only one compound and single-layer electron transport layers containing multiple compounds. Alternatively, the electron transport region can be a multilayer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0153] In this invention, the electron transport layer material may be selected from, but is not limited to, one or more combinations of ET-1 to ET-57 listed below:

[0154] The device also includes an electron injection layer located between the electron transport layer and the cathode. The electron injection layer material includes, but is not limited to, one or more combinations of the following: LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, and Ca.

[0155] To further describe the present invention, more specific device embodiments are listed below.

[0156] Device Example 1

[0157] All example devices were subjected to high vacuum (<10) -7 It is manufactured using a thermal evaporation method. The anode electrode is 1200 Å indium tin oxide (ITO). The cathode consists of 10 Å Liq (lithium 8-hydroxyquinoline) followed by 1000 Å Al. All devices are immediately sealed with epoxy-sealed glass lids in a nitrogen glove box (H2O and O2 < 1 ppm) after fabrication, and a desiccant is incorporated into the packaging. The organic stack of the device example consists of the following components in sequence: an ITO surface, 100 Å of HT-13 as a hole injection layer (HIL); 400 Å of HT-13 as a hole transport layer (HTL); 50 Å of EBM as an electron blocking layer (EBL); a light-emitting layer (EML) formed by evaporating a red host material RH-01 and a phosphorescent dopant compound I-1 at a rate ratio of 97:3, with a thickness of 400 Å; and 350 Å of Liq (lithium 8-hydroxyquinoline) doped with 35% ET-13 as an electron transport layer (ETL) deposited thereon.

[0158] Table 2 shows the thickness and material of the device layers.

[0159] Table 2. Materials and Thickness of Device Layers

[0160] Device Examples 2-18

[0161] Organic electroluminescent devices were prepared using the same method as in Device Example 1, except that the dopant material I-1 was replaced with I-3, I-6, I-13, I-15, I-31, I-41, I-58, I-69, I-70, I-72, I-80, I-97, I-99, I-103, I-105, I-116, and I-120, respectively.

[0162] Device Comparison Examples 1-8

[0163] Organic electroluminescent devices were prepared using the same method as in Device Example 1, except that the compounds of Comparative Examples 1-8 were used instead of the dopant compound I-1 in Example 1.

[0164] The structures of EBM, RH-01, and Comparative Examples 1-8 are as follows:

[0165] The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in the above-mentioned device embodiments and comparative examples were characterized at a brightness of 6000 nits. The test results are shown in Table 3 below:

[0166] Table 3

[0167] As can be seen from Table 3, compared with the organic electroluminescent devices prepared by the comparative example, the organic electroluminescent devices prepared using the compounds provided by the present invention as doping materials for the light-emitting layer have the advantages of the present invention. By selecting specific ligand compounds and substituting specific substituents at the 3-position of dibenzothiophene, the spatial configuration and stereostructure between molecules can be changed, the molecular orientation can be set, and the special device performance of improved turn-on voltage and low driving voltage can be achieved. This also improves the crosstalk phenomenon between sub-pixels and makes the OLED device have the advantages of long life, high efficiency and low driving voltage.

[0168] The above embodiments only list the effect data of devices made from a portion of the structures. This is a representative sampling test. Based on the experimental data, the overall data is not significantly different and can represent the effects of other unlisted structures.

[0169] In this invention, Formula I-3 has substituents at both the 3 and 4 positions of dibenzothiophene, while Comparative Example 5 has substituents only at the 4 position. This results in a 0.1V increase in turn-on voltage and a 0.2V decrease in drive voltage, leading to an approximately 24% increase in efficiency and a 300-hour increase in lifetime, demonstrating a significant performance improvement.

[0170] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organic electroluminescent material, characterized in that, The structure of the organic electroluminescent material is shown in formula I: in, R is selected from any one of -D (deuterium), -T (tritium), -F, -CN, -CT3, -CF3, -CH2F, -CHF2, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted 4-24 membered aromatic heterocyclic groups; R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 R 11 It is independently selected from any one of -H, -D (deuterium), -T (tritium), -F, -CN, -CD3, -CT3, -CF3, -CH2F, -CHF2, -Ge(Me)3, -Si(Me)3, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted 4-24 membered aromatic heterocyclic groups.

2. The organic electroluminescent material according to claim 1, characterized in that All atoms in the group can be replaced by deuterium.

3. The organic electroluminescent material according to claim 1 or 2, characterized in that R is selected from -D, -F, -CN, -CF3, -CH2F, -CHF2, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, biphenyl, fluorenyl, phenanthrene, triphenylene, furanyl, benzofuranyl, benzothiophene, dibenzofuranyl, dibenzothiophene, or any of the following substituents: R1-R 11 Independently selected from -H, -D (deuterium), -T (tritium), -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -Ge(Me)3, -Si(Me)3, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, thiacyclopentane, phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, Any one of phenanthrene, anthracene, indene, triphenylene, fluoranthracene, furanyl, thiophene, imidazolyl, pyrazolyl, thiazolyl, pyridinyl, pyrazinyl, pyrimidinyl, benzofuranyl, benzothiophene, isobenzofuranyl, dibenzofuranyl, dibenzothiophene, benzimidazolyl, benzothiazolyl, benziisothiazolyl, benzothiadiazolyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, and carbazoleyl.

4. The organic electroluminescent material according to claim 3, characterized in that R is selected from the group consisting of methyl, ethyl, -F, -CN, -CF3, or any one of the following substituents: R1is hydrogen, methyl, ethyl, -F, -CN, -CF3, or any one of the following substituents: R2 and R3 are independently selected from -H or -D.

5. The organic electroluminescent material according to claim 1, characterized in that, The structure of the organic electroluminescent material includes, but is not limited to, any one of the following compounds:

6. A method of producing an organic electroluminescent material according to claim 1, wherein The procedure is as follows: (1) Under nitrogen protection, the ligand LA structure compound and IrCl3·3H2O were placed in the reaction system, and a mixed solution of ethylene glycol ethyl ether and pure water was added. The reaction was refluxed under nitrogen protection and then cooled to room temperature. A precipitate was formed. The precipitate was filtered, washed with water, anhydrous ethanol and petroleum ether in sequence and dried to obtain the bridged ligand compound shown in intermediate formula II. (2) Weigh the intermediate compound of formula II and anhydrous potassium carbonate, add ethylene glycol ethyl ether, then add the ligand compound of formula LB, reflux under nitrogen protection, filter, wash with alcohol, and dry; use dichloromethane as solvent, perform silica gel column chromatography, concentrate the filtrate and precipitate the solid to obtain compound of formula I; A specific synthesis route is as follows: wherein R, R1-R 11 selected from the definitions given in claim 1.

7. Use of an organic electroluminescent material, characterized in that The organic electroluminescent material as described in any one of claims 1-5 is applied to an organic electroluminescent device.

8. Use according to claim 7, characterized in that, The organic electroluminescent device includes an organic layer; the organic layer contains the organic electroluminescent material as described in any one of claims 1-5.

9. Use according to claim 8, characterized in that, The organic electroluminescent material serves as a dopant in the light-emitting layer.

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