Metal iridium complex, preparation method thereof and organic electroluminescent device

Abstract

The invention provides a metal iridium complex, a preparation method thereof and an organic electroluminescent device, and belongs to the field of organic electroluminescent materials, and the structure of the metal iridium complex is shown as a formula I. According to the metal iridium complex, the intermolecular steric configuration is improved, the intermolecular bond angle is reduced, the service life is prolonged, and the organic electroluminescent device has the advantages that the organic electroluminescent device is simple in preparation method and easy to implement. The metal iridium complex has good space torsion capability, so that carrier migration is avoided, the wavelength of the metal iridium complex can be adjusted after the metal iridium complex is used as a specific doping material of a luminescent layer and applied to an organic electroluminescent device, the metal iridium complex has low voltage, the power efficiency is obviously improved, and the metal iridium complex has the characteristics of low evaporation temperature, high photo-electrochemical stability, high luminous efficiency and the like. In addition, the preparation method of the metal iridium complex is simple in process, high in product purity and suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the field of organic electroluminescent materials, and in particular relates to a metal iridium complex and a preparation method thereof, as well as an organic electroluminescent device. Background Art

[0002] Organic light-emitting diodes (OLEDs), a next-generation display technology, are gaining increasing attention in both display and lighting applications, boasting a broad range of applications. However, compared to market requirements, OLED device performance, including luminous efficiency, driving voltage, and lifespan, still requires further improvement.

[0003] Generally speaking, the basic structure of an OLED device consists of a thin film of organic materials with various functions sandwiched between metal electrodes. Driven by an electric current, holes and electrons are injected from the cathode and anode, respectively. After traveling a certain distance, the holes and electrons recombine in the light-emitting layer and release the energy as light or heat, thus generating the OLED's luminescence. However, organic functional materials are the core components of organic electroluminescent devices, and the material's thermal stability, photochemical stability, electrochemical stability, quantum yield, film-forming stability, crystallinity, and color saturation are all major factors affecting device performance.

[0004] Generally, organic functional materials include fluorescent materials and phosphorescent materials. Fluorescent materials are typically small organic molecules and can only utilize 25% of their singlet exciton energy, resulting in relatively low luminescence efficiency. Phosphorescent materials, on the other hand, utilize the energy of 75% of triplet excitons in addition to the 25% of singlet excitons due to the spin-orbit coupling effect caused by the heavy atom effect, resulting in higher luminescence efficiency.

[0005] Compared with fluorescent materials, phosphorescent materials started later, and the thermal stability, lifespan, and color saturation of the currently disclosed organic phosphorescent materials need to be improved. CN107973823A discloses a class of quinoline iridium compounds. The color saturation and device performance of this class of compounds, especially the luminous efficiency and device life, need to be improved; CN106459114A discloses a class of iridium compounds coordinated by β-diketone ligands. This class of compounds has a high sublimation temperature and poor color saturation, especially the device luminous efficiency and device life are not ideal, and need further improvement; CN111377969A discloses a class of dibenzofuran-isoquinoline iridium complexes. The device performance of this class of materials, especially the color saturation, cannot meet the display color gamut requirements of BT2020 and need to be further improved.

[0006] Therefore, how to develop a metal iridium complex material with high luminous efficiency, low voltage, low evaporation temperature, high optical and electrochemical stability, high luminous efficiency and long device life is a technical problem that needs to be solved at present. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention aims to provide a metal iridium complex and a preparation method thereof, as well as an organic electroluminescent device.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In one aspect, the present invention provides a metal iridium complex having a structure of (La)2IrLb, specifically as shown in Formula I:

[0010] ;

[0011] wherein X is independently selected from O, S, Se, NRx, CRxRy, SiRxRy or GeRxRy, and Rx and Ry are independently selected from hydrogen, methyl, -F, -D, -CN, -CD3 or phenyl;

[0012] R1, R2, R3, R4 and R5 are independently selected from any one or a combination of at least two of hydrogen, deuterium, halogen, -CN, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C3-C20 heterocyclyl, substituted or unsubstituted C6-C30 aryl, trimethylgermanium or trimethylsilyl;

[0013] Ra are each independently selected from any one or more combinations of hydrogen, -D, -CN, -F, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C10 cycloalkyl, and Ra may be monosubstituted or polysubstituted;

[0014] Ring A is independently selected from absent, substituted or unsubstituted C6-C18 aromatic rings, C6-C18 heteroaromatic rings;

[0015] R6, R7 and R8 are each independently selected from any one or a combination of at least two of hydrogen, -D, -CN, -F, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, substituted or unsubstituted C3-C10 cycloalkyl, and substituted or unsubstituted heterocycloalkyl;

[0016] The substituents in the substituted group are selected from -D, C1-C6 alkyl, -F, -CN, trimethylgermanyl, trimethylsilyl, C3-C10 cycloalkyl, or are substituted by two or more substituents connected to each other among the substituents shown above, or have no substituents.

[0017] The hydrogen atoms in formula I are unsubstituted, partially substituted or fully substituted by deuterium.

[0018] In the present invention, D represents deuterium.

[0019] Furthermore,

[0020] X is independently selected from O, S, Se, NRx, CRxRy, SiRxRy or GeRxRy, Rx and Ry are independently selected from hydrogen, methyl;

[0021] R1, R2, R3, R4 and R5 are each independently selected from hydrogen, -F, -CD3, -D, -CN, substituted or unsubstituted phenyl, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted butyl, substituted or unsubstituted pentyl, substituted or unsubstituted cyclopentyl, any one or a combination of at least two of trimethylsilyl or trimethylgermanium;

[0022] R a is independently selected from -F, -CD3, -D, -CN, substituted or unsubstituted phenyl, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted butyl, substituted or unsubstituted pentyl, substituted or unsubstituted cyclopentyl;

[0023] A is selected from absent, substituted or unsubstituted phenyl, and substituted or unsubstituted naphthyl.

[0024] Going a step further, The specific structure is preferably as follows:

[0025]

[0026] .

[0027] Preferably, R6, R7 and R8 are each independently selected from any one or a combination of at least two of hydrogen, -F, -D, -CN, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted butyl, substituted or unsubstituted pentyl, substituted or unsubstituted cyclopropyl, and substituted or unsubstituted cyclopentyl;

[0028] Preferably, the substituted methyl group may be -CD3, CF3 or CD2F.

[0029] In the present invention, The specific structure is preferably as follows:

[0030]

[0031] Where D stands for deuterium.

[0032] As a further embodiment of the present invention, hydrogen in the above-mentioned groups or substituent groups may be substituted with deuterium.

[0033] As a further embodiment of the present invention, the metal iridium complex is selected from any one of the following structures, but not limited thereto:

[0034]

[0035] Where D stands for deuterium.

[0036] It should be noted that only some specific structural forms are listed above, but this series of metal iridium complexes is not limited to the above molecular structures. Any simple transformation of some simple groups and their substituted groups and substitution positions can obtain other specific molecular structures, which will not be repeated here.

[0037] A second object of the present invention is to provide a method for preparing the above-mentioned metal iridium complex. The metal iridium complex of the present invention can be prepared by methods known to those skilled in the art. Alternatively, the following reaction scheme is preferably used for preparation, comprising the following steps:

[0038] (1) Providing a compound represented by the following formula II:

[0039]

[0040] (2) reacting the compound of formula II provided in step (1) with iridium trichloride to obtain a compound of formula III:

[0041]

[0042] (3) Providing a compound represented by the following formula IV:

[0043]

[0044] (4) reacting the compound represented by formula IV provided in step (3) with the compound represented by formula III obtained in step (2) to obtain a metal iridium complex represented by formula I;

[0045]

[0046] Wherein, the groups represented by R1, R2, R3, R4, R5, Ra and A are the same as those described above.

[0047] As a further embodiment of the present invention, the compound II provided in step (1) is reacted with iridium trichloride, and the molar ratio of the compound II to the iridium trichloride is (2.2-2.5):1, for example, 2.2:1, 2.3:1, 2.4:1 or 2.5:1.

[0048] Preferably, in the reaction of the compound of formula II provided in step (1) with iridium trichloride (IrCl3), the solvent is a mixed solution of ethylene glycol ethyl ether and ultrapure water, the volume ratio of the ethylene glycol ethyl ether and the ultrapure water is 3:1, the amount of the solvent is 30 times the mass of the iridium trichloride, under a nitrogen protection system, formula II, IrCl3·3H2O (1 eq) is taken into the reaction system, a mixed solution of ethylene glycol ethyl ether and pure water is added, under nitrogen protection, refluxing at 110°C for 24h, and then cooling to room temperature, a precipitate is separated out, the precipitate is suction filtered, washed with water, anhydrous ethanol and petroleum ether in sequence, and dried at 50°C for at least 10h to obtain the bridged ligand of formula III.

[0049] Further, in the reaction of the compound of formula IV provided in step (3) with the compound of formula III obtained in step (2), the molar ratio of the compound of formula III to the compound of formula IV is 1:2.5. The reaction is carried out in the presence of a base, the base used is anhydrous potassium carbonate or anhydrous sodium carbonate, the reaction is carried out in a solvent, the solvent is ethylene glycol ethyl ether, the amount of the solvent is 30 times the mass of the compound of formula III, under a nitrogen protection system, formula III compound (1 eq) is taken, anhydrous potassium carbonate (10 eq) is added, ethylene glycol ethyl ether is added to the system, and nitrogen is replaced for three times, the compound of formula IV is added under nitrogen, under nitrogen protection, refluxing at 110°C for 24h, cooling, suction filtration, alcohol washing, drying at 50°C for at least 10h, using dichloromethane as a solvent, using silica gel column chromatography, concentrating the filtrate to obtain a solid, and the final compound of formula I is obtained.

[0050] A third object of the present application is to provide the application of the above-mentioned metal iridium complex in an organic electroluminescent device.

[0051] The present application provides an organic electroluminescent device comprising the metal iridium complex as described above.

[0052] Further preferably, the organic electroluminescent device comprises a first electrode, a second electrode and an organic layer disposed between the first electrode and the second electrode, and the organic layer comprises the metal iridium complex of the present application.

[0053] In the present application, the organic layer comprises at least one functional layer, i.e. the metal iridium complex of the present application.

[0054] In the present application, the organic layer comprises a light-emitting layer, and the light-emitting layer comprises the metal iridium complex of the present application.

[0055] In the present invention, the light-emitting layer of the organic electroluminescent device includes a host material and a dopant material, the dopant material is the metal iridium complex described in the present invention, and the mixing mass ratio of the host material to the dopant material is 90:10~99.5:0.5, for example, 90:10, 91:9, 92:8, 93:7, 94:6, 95:5, 96:4, 97:3, 98:2 or 99:1.

[0056] In the present invention, the metal iridium complex is in a single form or mixed with other substances and exists in the organic layer.

[0057] Preferably, the organic layer further includes a hole injection layer, a hole transport layer, a layer having both hole injection and hole transport skills, an electron blocking 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.

[0058] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0059] The present invention generates a metal iridium complex by selecting a specific alkyl ligand for combination, changing the combination of substituents on the ligand, and adding a branched alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted alkyl group. The intermolecular spatial configuration is improved, the intermolecular bond angle is reduced, the lifespan is increased, and the complex has good spatial twisting ability, thereby avoiding carrier migration. When the complex is used as a specific doping material for a light-emitting layer and applied to an organic electroluminescent device, the wavelength of the metal iridium complex can be adjusted, the voltage is low, and the power efficiency is significantly improved. The complex has the advantages of low evaporation temperature, high light and electrochemical stability, high luminous efficiency, long device life, and the like. In addition, the preparation method of the metal iridium complex of the present invention is simple in process, the product has high purity, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is the H NMR spectrum of compound Z-1. DETAILED DESCRIPTION

[0061] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0062] In addition, it should be noted that the numerical values ​​given in the following examples are as accurate as possible, but those skilled in the art understand that due to unavoidable measurement errors and experimental operation problems, each number should be understood as an approximate number rather than an absolutely accurate value.

[0063] Example 1

[0064]

[0065] Under nitrogen protection, 3,6-dibromo-2-methylaniline (1 eq, CAS: 1263376-95-9), K3PO4·3H2O (3 eq) was placed into the reaction system, 1.4-dioxane was added, and DBA palladium (tris(dibenzylideneacetone)dipalladium, 0.01 eq) and S-Phos (2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl, 0.1 eq) were added under nitrogen protection. Diboric acid pinacol ester (1 eq, CAS: 73183-34-3) was added in three batches every 1 hour. After the addition, the mixture was refluxed at 100°C for 24 h under nitrogen protection, then cooled to 25°C and concentrated under reduced pressure. The crude product was subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA (ethyl acetate): PE (petroleum ether) in a volume ratio of 1:15. The receiving solution was vortexed until no liquid flowed out and dried in vacuo to obtain the intermediate 1 shown in FIG. The yield was 66.7%.

[0066]

[0067] Under nitrogen protection, intermediate 1 (1 eq) and anhydrous potassium carbonate (3 eq) were placed in a reaction system, and toluene, anhydrous ethanol, and purified water were added. Pd(PPh3)4 (tetrakis(triphenylphosphine)palladium, 0.015 eq) was added under nitrogen protection, and 5-bromo-4-chloro-6-(methylthio)pyrimidine (1 eq, CAS: 1289199-12-7) was added in three batches every 1 hour. After the addition was completed, the mixture was refluxed at 70°C for 24 hours under nitrogen protection and then cooled to 25°C. After the reaction was cooled, it was extracted with ethyl acetate, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The crude product was subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA:PE (volume ratio) = 1:10. The receiving solution was vortexed until no liquid flowed out and dried under vacuum to obtain the intermediate 2 shown in FIG. 2 with a yield of 57.7%.

[0068]

[0069] Under nitrogen protection, intermediate 2 (1 eq) was added with tetrahydrofuran and glacial acetic acid, and the mixture was stirred at -10°C for 10 minutes. Tert-butyl nitrite was added under nitrogen protection, and the mixture was reacted at -10°C for 2 hours, and then returned to room temperature for 2 hours. After the reaction was completed, the mixture was diluted with water, and the crude product was subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA:PE in a volume ratio of 1:10. The receiving solution was vortexed until no liquid flowed out, and then dried in vacuo to obtain the compound intermediate 3 shown in the figure, with a yield of 55.6%.

[0070]

[0071] Under nitrogen protection, intermediate 3 (1 eq) and anhydrous potassium carbonate (3 eq) were placed in a reaction system, and toluene, anhydrous ethanol, and purified water were added. Pd(PPh3)4 (0.015 eq) was added under nitrogen protection, and tert-butylboric acid (1 eq, CAS: 86253-12-5) was added in three batches every 1 hour. After the addition was completed, the mixture was refluxed at 100°C for 24 hours under nitrogen protection and then cooled to 25°C. After the reaction was cooled, it was extracted with ethyl acetate, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The crude product was subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA:PE in a volume ratio of 1:20. The receiving solution was vortexed until no liquid flowed out and dried in vacuo to obtain the intermediate 4 shown in the figure with a yield of 49.8%.

[0072]

[0073] Under nitrogen protection, intermediate 4 (1 eq) and anhydrous potassium carbonate (3 eq) were placed in a reaction system, and toluene, anhydrous ethanol, and purified water were added. Pd(PPh3)4 (0.015 eq) was added under nitrogen protection, and (4-tert-butylnaphthalen-2-yl)boric acid (1 eq, CAS: 2387377-70-8) was added in three batches every 1 hour. After the addition was completed, the mixture was refluxed at 100°C for 24 hours under nitrogen protection and then cooled to 25°C. After the reaction was cooled, it was extracted with ethyl acetate, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The crude product was subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA:PE in a volume ratio of 1:10. The receiving solution was vortexed until no liquid flowed out and dried in vacuo to obtain compound II-1 with a yield of 91.2%.

[0074]

[0075] Under a nitrogen protection system, ligand II-1 (2.5 eq) and IrC13·3H2O (1 eq) were put into the reaction system, and a mixed solution of ethylene glycol ethyl ether and purified water was added. The mixture was refluxed at 110°C for 24 hours under nitrogen protection, and then cooled to room temperature. A precipitate was precipitated, filtered, washed with water, anhydrous ethanol, and petroleum ether in sequence, and dried at 50°C for at least 10 hours to obtain a bridged ligand of formula III-1 with a yield of 53%.

[0076]

[0077] Under nitrogen protection, ligand III-1 (1 eq) was taken, anhydrous potassium carbonate (10 eq) was added, and ethylene glycol ethyl ether was added to the system, and nitrogen was replaced three times. 3,7-diethylnonane-4,6-dione (CAS: 872802-98-7, 2.5 eq) was added under nitrogen. Under nitrogen protection, the mixture was refluxed at 110°C for 24 h, cooled, filtered, washed with alcohol, and dried at 50°C for at least 10 h. Dichloromethane was used as the solvent, and silica gel column chromatography was used. The filtrate was concentrated to precipitate the solid to obtain the final compound Z-1 (11.78 g, yield 59.6%).

[0078] HPLC purity: greater than 99.5%;

[0079] MS (ESI, m / Z): [M+H]+: 1306.69.

[0080] The H NMR spectrum of compound Z-1 is shown in Figure 1 shown.

[0081] Example 2

[0082]

[0083] Under nitrogen protection, intermediate 4 (1 eq) and anhydrous potassium carbonate (3 eq) were placed in a reaction system, and toluene, anhydrous ethanol, and purified water were added. Pd(PPh3)4 (0.015 eq) was added under nitrogen protection, and (4-chloronaphthalen-2-yl)boric acid (1 eq, CAS: 2575133-50-3) was added in three batches every 1 hour. After the addition, the mixture was refluxed at 100°C for 24 hours under nitrogen protection and then cooled to 25°C. After the reaction was cooled, it was extracted with ethyl acetate, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The crude product was subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA:PE (volume ratio) = 1:50. The receiving solution was vortexed until no liquid flowed out and dried under vacuum to obtain the intermediate 5 shown in FIG. 5 with a yield of 89.8%.

[0084]

[0085] Under nitrogen protection, intermediate 5 (1 eq) and anhydrous potassium carbonate (3 eq) were placed in a reaction system, and toluene, anhydrous ethanol, and purified water were added. Pd(PPh3)4 (0.015 eq) was added under nitrogen protection, and tert-butylboric acid (1 eq, CAS: 86253-12-5) was added in three batches every 1 hour. After the addition was completed, the mixture was refluxed at 100°C for 24 hours under nitrogen protection, and then cooled to 25°C. After the reaction was cooled, it was extracted with ethyl acetate, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The crude product was subjected to column chromatography (200-300 mesh, 500 g) to remove impurities. The developing solvent was EA:PE by volume ratio = 1:50. The receiving solution was vortexed until no liquid flowed out, and then dried under vacuum to obtain the compound of formula II-1 with a yield of 89.6%.

[0086]

[0087] Under a nitrogen protection system, ligand II-88 (2.5 eq) and IrC13·3H2O (1 eq) were put into the reaction system, and a mixed solution of ethylene glycol ethyl ether and purified water was added. The mixture was refluxed at 110°C for 24 hours under nitrogen protection, and then cooled to room temperature. A precipitate was precipitated, filtered, washed with water, anhydrous ethanol, and petroleum ether in sequence, and dried at 50°C for at least 10 hours to obtain a bridged ligand III-88 with a yield of 52%.

[0088]

[0089] Under nitrogen protection, ligand III-88 (1 eq) was taken, anhydrous potassium carbonate (10 eq) was added, and ethylene glycol ethyl ether was added to the system, and nitrogen was replaced three times. 3,7-diethylnonane-4,6-dione (CAS: 872802-98-7, 2.5 eq) was added under nitrogen. Under nitrogen protection, the mixture was refluxed at 110°C for 24 h, cooled, filtered, washed with alcohol, and dried at 50°C for at least 10 h. Dichloromethane was used as the solvent, and silica gel column chromatography was used. The filtrate was concentrated to precipitate the solid to obtain the final compound Z-1 (13.68 g, yield 52.3%).

[0090] HPLC purity: greater than 99.5%;

[0091] MS (ESI, m / Z): [M+H]+: 1334.75.

[0092] In the embodiments of the present invention, the preparation methods of the metal iridium complexes represented by other formulas Z-1 to Z-1062 are basically the same as the methods in the above embodiments, and only the corresponding raw materials need to be replaced, which will not be described in detail here.

[0093] Device Example 1

[0094] The metal iridium complex Z-1 prepared in Example 1 was used to prepare an organic electroluminescent device. The specific method is as follows:

[0095] The ITO glass substrate with a coating thickness of 1500Å was washed three times in distilled water, ultrasonically washed for 30 minutes, and then repeatedly washed three times with distilled water, ultrasonically washed for 30 minutes. After the distilled water washing, it was ultrasonically washed in sequence with isopropyl alcohol, acetone, methanol and other solvents. After drying, it was transferred to a plasma cleaning machine, the above ITO glass substrate was washed for 5 minutes, and then sent to the evaporation machine; under vacuum conditions, the standard pressure was set to 1×10 -6 torr, and then organic layers were formed on the ITO glass substrate in the order of CuPc (200Å), NPB (400Å), CBP+metal iridium complex Z-1 (200Å), Alq3 (300Å), LiF (5Å) and Al (1000Å).

[0096] The CBP+metal iridium complex Z-1 is represented by CBP doped with 5% (mass) of metal iridium complex Z-1 for vapor deposition.

[0097] The structural formulas of CuPc, NPB, CBP and Alq3 used in the device examples are as follows:

[0098]

[0099] Device Example 2-Device Example 50

[0100] Referring to the method of the device embodiment 1, the only difference is that the dopant compound formula Z-1 is replaced by Z-8, Z-18, Z-22, Z-57, Z-78, Z-100, Z-144, Z-166, Z-173, Z-206, Z-255, Z-270, Z-311, Z-341, Z-356, Z-413, Z-430, Z-464, Z-480, Z-503, Z-540, Z-566, Z-579, Z-592, Z- -603, Z-606, Z-622, Z-633, Z-667, Z-680, Z-693, Z-716, Z-744, Z-758, Z-786, Z-792, Z-804, Z-846, Z-866, Z-889, Z-910, Z-919, Z-930, Z-950, Z-961, Z-973, Z-988, Z-1002, Z-1032, and then an organic electroluminescent device was prepared according to the same method as in Device Example 1.

[0101] Device Comparative Example 1-Device Comparative Example 6

[0102] An organic electroluminescent device was prepared in the same manner as in Example 1, except that (btp)2Ir(acac), the compounds of Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5, and Comparative Example 6 were used to replace the dopant compound Z-1 in Example 1. The specific structures are as follows:

[0103]

[0104] The driving voltage, luminous efficiency and lifespan of the organic electroluminescent devices obtained from the above device examples and device comparative examples were characterized at a brightness of 8000 (nits). The test results are shown in Table 1.

[0105] It should be noted that the relative value is the result of a comparison between numbers. The relative value is usually expressed as a percentage or decimal, and is used to indicate the degree of change of a number relative to other numbers. In addition, in the industrial field, the relative value can also be used to measure the degree of change in production efficiency, as well as to evaluate product quality and stability.

[0106] Table 1 Performance test results

[0107]

[0108]

[0109] As shown in Table 1, under the same current conditions, the organic electroluminescent device prepared from the metal iridium complex of the present invention is generated by selecting a ligand with a specific alkyl group, changing the combination of substituents on the ligand, and adding branched alkyl groups, substituted or unsubstituted aryl groups, and substituted or unsubstituted alkyl groups to form a metal iridium complex, thereby improving the intermolecular spatial configuration and having good spatial twisting ability, thereby avoiding carrier migration. When it is used as a specific doping material for the light-emitting layer and applied to an organic electroluminescent device, the wavelength of the metal iridium complex can be adjusted, with a lower voltage and significantly improved power efficiency. It has the advantages of low evaporation temperature, high light and electrochemical stability, high luminous efficiency, and long device life. In addition, the preparation method provided in the embodiment of the invention has a simple process, the prepared product has high purity, and is suitable for industrial production.

[0110] The applicant declares that while the present invention uses the above-described embodiments to illustrate the metal iridium complex, its preparation method, and the organic electroluminescent device, the present invention is not limited to these embodiments, nor does it imply that the present invention must rely on these embodiments for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A metal iridium complex, characterized in that The structure of the metal iridium complex is (La)2IrLb, as shown in Formula I: ； wherein X is independently selected from O, S, Se, NRx, CRxRy, SiRxRy or GeRxRy, and Rx and Ry are independently selected from hydrogen, methyl, -F, -D, -CN, -CD3 or phenyl; R1, R2, R3, R4 and R5 are independently selected from any one or a combination of at least two of hydrogen, deuterium, halogen, -CN, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C3-C20 heterocyclyl, substituted or unsubstituted C6-C30 aryl, trimethylgermanium or trimethylsilyl; Ra are each independently selected from any one or more combinations of hydrogen, -D, -CN, -F, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C30 aryl, and substituted or unsubstituted C3-C10 cycloalkyl, and Ra is monosubstituted or polysubstituted; Ring A is independently selected from absent, substituted or unsubstituted C6-C18 aromatic rings, C6-C18 heteroaromatic rings; R6, R7 and R8 are each independently selected from any one or a combination of at least two of hydrogen, -D, -CN, -F, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, substituted or unsubstituted C3-C10 cycloalkyl, and substituted or unsubstituted heterocycloalkyl; The substituents in the substituted group are selected from -D, C1-C6 alkyl, -F, -CN, trimethylgermanyl, trimethylsilyl, C3-C10 cycloalkyl, or substituted by two or more substituents connected to each other among the substituents shown above; The hydrogen atoms in formula I are unsubstituted, partially substituted or fully substituted by deuterium.

2. The metal iridium complex according to claim 1, characterized in that X is independently selected from O, S, Se, NRx, CRxRy, SiRxRy or GeRxRy, Rx and Ry are independently selected from hydrogen, methyl; R1, R2, R3, R4 and R5 are each independently selected from hydrogen, -F, -CD3, -D, -CN, substituted or unsubstituted phenyl, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted butyl, substituted or unsubstituted pentyl, substituted or unsubstituted cyclopentyl, any one or a combination of at least two of trimethylsilyl or trimethylgermanium; R a is independently selected from -F, -CD3, -D, -CN, substituted or unsubstituted phenyl, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted butyl, substituted or unsubstituted pentyl, substituted or unsubstituted cyclopentyl; A is selected from absent, substituted or unsubstituted phenyl, and substituted or unsubstituted naphthyl.

3. The metal iridium complex according to claim 1, characterized in that Selected from the following structures: ； ； ； ； ； ； 。 4. The metal iridium complex according to claim 1, characterized in that R6, R7 and R8 are each independently selected from any one or a combination of at least two of hydrogen, -F, -D, -CN, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted propyl, substituted or unsubstituted butyl, substituted or unsubstituted pentyl, substituted or unsubstituted cyclopropyl, and substituted or unsubstituted cyclopentyl; The substituted methyl group is -CD3, CF3 or CD2F.

5. The metal iridium complex according to claim 1, characterized in that Select any one of the following structures: ； ； Where D stands for deuterium.

6. The metal iridium complex according to claim 1, characterized in that The metal iridium complex is selected from any one of the following structures: Where D stands for deuterium.

7. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises the metal iridium complex according to any one of claims 1 to 6.

8. The organic electroluminescent device according to claim 7, characterized in that: The organic electroluminescent device includes a first electrode, a second electrode, and an organic layer disposed between the first electrode and the second electrode. The organic layer includes a light-emitting layer. The light-emitting layer includes a host material and a doping material. The doping material is the metal iridium complex according to any one of claims 1 to 6.

9. The organic electroluminescent device according to claim 8, characterized in that: The mass ratio of the main material to the doping material is 90:10~99.5:0.

5.

10. The organic electroluminescent device according to claim 8, characterized in that: The organic layer further includes a hole injection layer, a hole transport layer, a layer having both hole injection and hole transport skills, an electron blocking 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 the above.

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