An organic metal compound and an organic electroluminescent device containing the same

Abstract

The present invention provides an organometallic compound and an organic electroluminescent device containing the same. The present invention belongs to the field of organic photoelectric materials. The organometallic compound of the present invention has a structure shown in General Formula I. The present invention generates the organometallic compound by changing the combination of substituents on 2-(dibenzo[b,d]furan-4-yl)pyridine to add -CN, -F, a branched alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted cycloalkyl group. This improves the intermolecular spatial configuration and has good spatial torsion ability, thereby avoiding carrier migration. When the organometallic compound is used as a specific doping material for a light-emitting layer and applied to an organic electroluminescent device, the driving voltage of the device is reduced, thereby avoiding carrier migration. The driving voltage is significantly reduced, and the luminous efficiency and life are significantly improved.

Description

Technical Field

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

[0002] Organic electroluminescent device (OLED) is a device that changes electrical energy into light by applying electricity to an organic electroluminescent material, and generally has a structure comprising an anode, a cathode, and an organic layer between the anode and the cathode. The organic layer of the organic EL device can be composed of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer (which comprises a host material and a doping material), an electron buffer layer, a hole blocking layer, an electron transport layer, an electron injection layer, etc., and the materials used for the organic layer are classified into hole injection materials, hole transport materials, electron blocking materials, light-emitting materials, electron buffer materials, hole blocking materials, electron transport materials, electron injection materials, etc. by their functions. In the organic EL device, due to the application of voltage, holes are injected into the light-emitting layer from the anode, and electrons are injected into the light-emitting layer from the cathode, and high-energy excitons are formed by the recombination of holes and electrons. Through this energy, the organic light-emitting compound reaches an excited state, and luminescence is generated by emitting light due to the energy generated by the excited state of the organic light-emitting compound returning to the ground state.

[0003] However, existing organic electroluminescent materials have low stability, and the HOMO and LUMO energy levels are poorly matched with adjacent energy levels, resulting in an imbalance in carrier mobility. This in turn causes organic electroluminescent devices containing these organic electroluminescent materials to have high driving voltages, low luminous efficiency, and short lifespans, severely limiting their application. Therefore, how to develop a high-performance luminescent material that enables organic electroluminescent devices to have comprehensive characteristics such as high efficiency, long life, and low voltage is a technical problem that researchers in this field urgently need to solve. Summary of the Invention

[0004] To address the shortcomings of the prior art, the present invention aims to provide an organometallic compound and an organic electroluminescent device containing the same. The present invention generates an organometallic compound by modifying the substituent combination on 2-(dibenzo[b,d]furan-4-yl)pyridine, adding -CN, -F, a branched alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted cycloalkyl group. The addition of electron-withdrawing groups improves the intermolecular spatial configuration and provides improved spatial torsion, thereby preventing carrier migration. When the compound is used as a specific dopant material in the light-emitting layer of an organic electroluminescent device, the device's startup voltage is reduced, thereby preventing carrier migration. Furthermore, the driving voltage is significantly lowered, and the luminous efficiency and lifetime are significantly improved.

[0005] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0006] In one aspect, the present invention provides an organometallic compound having a structure shown in Formula I:

[0007]

[0008] wherein R1, R2, R3, R4, R5 and R6 are each independently selected from any one or a combination of at least two of hydrogen, -D, -CD3, -CD2, -T, -CN, -F, -CT3, -CF3, -CH2F, -CHF2, a substituted or unsubstituted C1-C6 alkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C3-C24 heteroaryl group, a substituted or unsubstituted C2-C6 alkynyl group, a substituted or unsubstituted methoxy group, trimethylgermanium, and trimethylsilyl;

[0009] R7, R8, R9, R 10 、R 11 、R 12 、R 13 and R 14 Each is independently selected from any one or a combination of at least two of hydrogen, -D, -T, -CN, -F, -CT3, -CF3, -CH2F, -CHF2, C1-C6 alkyl which is fully or partially substituted with deuterium, cyclopentyl, cyclohexyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C24 heteroaryl, substituted or unsubstituted C2-C6 alkynyl, substituted or unsubstituted C1-C40 alkoxy, substituted or unsubstituted C3-C15 cycloalkyl, trimethylgermanium or trimethylsilyl;

[0010] Ra and Rb are present simultaneously; wherein the number of substitutions of Ra is 1-3, and Rb is independently selected from -CN or -F;

[0011] Ra is selected from the following structures:

[0012]

[0013] Where R 15 、R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 、R 24 、R 25 、R 26 、R 27 、R 28 and R 29Each is independently selected from any one or a combination of at least two of hydrogen, -D, -T, -CN, -F, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C24 heteroaryl, substituted or unsubstituted C2-C6 alkynyl, substituted or unsubstituted C2-C15 heterocyclyl, substituted or unsubstituted C3-C15 cycloalkyl, substituted or unsubstituted methoxy, naphthyl, trimethylgermanium, and trimethylsilyl;

[0014] The hydrogen atoms in Formula I are all substituted with deuterium, partially substituted with deuterium, or not substituted with deuterium.

[0015] In the present invention, D represents deuterium and T represents tritium.

[0016] Further, R1, R2, R3, R4, R5 and R6 are each independently selected from any one or a combination of at least two of hydrogen, -D, -CN, -F, -CD3, -CF3, methyl, ethyl, propyl, butyl, pentyl, C1-C6 alkyl fully or partially substituted with deuterium, cyclopropyl, cyclopentyl, cyclohexyl, phenyl, phenyl substituted with pentyl, trimethylsilyl, and trimethylgermanium;

[0017] Furthermore, R7, R8, R9, R 10 、R 11 、R 12 、R 13 and R 14 Each is independently selected from any one or a combination of at least two of hydrogen, -D, -CN, -F, -CD3, -CF3, methyl, ethyl, propyl, butyl, pentyl, cyclopentyl, phenyl, deuterated phenyl, isobutyl, trimethylsilyl, trimethylgermanium, and a C1-C6 alkyl group which is fully or partially substituted with deuterium;

[0018] Furthermore, R 15 、R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 、R 24 、R 25 、R 26 、R 27 、R 28 and R 29Each is independently selected from any one or a combination of at least two of -F, -CN, -CD3, -CF3, -D, methyl, ethyl, propyl, butyl, pentyl, phenyl, deuterated ethyl, deuterated propyl, deuterated butyl, deuterated pentyl, biphenyl, C1-C6 alkyl-substituted phenyl, C1-C6 alkyl-substituted biphenyl, cyclopentyl, cyclopropyl, cyclohexyl, fluorine-substituted phenyl, cyano-substituted phenyl, deuterated benzene, trimethylgermanium, and trimethylsilyl;

[0019] In the present invention, the C1-C6 alkyl groups are each independently selected from one of substituted or unsubstituted linear alkyl groups, substituted or unsubstituted branched alkyl groups, and substituted or unsubstituted cycloalkyl groups; the C1-C6 alkyl groups are partially deuterated, fully deuterated, or undeuterated.

[0020] The C1-C6 alkyl group completely substituted by deuterium is preferably -CD3;

[0021] In the present invention, the substituents on the substituted group are selected from one or a combination of at least two of -F, -CN, -D, -CD3, -CF3, hydrogen, methyl, ethyl, propyl, butyl, pentyl, phenyl, biphenyl, cyclopentyl, cyclohexyl, cyclopropyl, deuterated ethyl, deuterated propyl, deuterated butyl, deuterated pentyl, pentyl-substituted phenyl, trimethylgermanium, and trimethylsilyl.

[0022] Furthermore, the organometallic compound is preferably selected from one of the following structures, but is not limited thereto:

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049] .

[0050] The second object of the present invention is to provide a method for preparing the above-mentioned organometallic compound.

[0051] In the present invention, the preparation process of the organometallic compound of formula I is as follows:

[0052] ;

[0053] Among them, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 、R 11 、R 12 、R 13 、R 14 、R 15 、R 16 , Ra and Rb are the same as defined above and will not be repeated here.

[0054] The preparation operation is as follows:

[0055] Under nitrogen protection, the ligand of formula V and IrC13·3H2O were placed in the reaction system, and a mixed solution of ethylene glycol ethyl ether and purified water was added, and the mixture was refluxed at 120°C for 36 hours under nitrogen protection to obtain the intermediate of formula IV;

[0056] Silver trifluoromethanesulfonate was added to the intermediate IV, and then dichloromethane and methanol were added to the system, and the mixture was refluxed at 25° C. for 48 hours under nitrogen protection to obtain the intermediate III;

[0057] Add the ligand of formula II to the intermediate of formula III, then add anhydrous ethanol to the system, and reflux at 80° C. for 36 hours under nitrogen protection to obtain the organometallic compound of formula I.

[0058] The third technical purpose of the present invention is to provide an organic electroluminescent device, which includes an anode, a cathode, and an organic material layer arranged between the anode and the cathode, and the organic material layer includes at least one of the organic metal compounds described above.

[0059] Preferably, the organic material layer includes a light-emitting layer, the light-emitting layer includes a host material and a doping material, and the doping material includes at least one of the organic metal compounds described above.

[0060] Preferably, the organic material layer further includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, an electron transport layer or an electron injection layer.

[0061] Preferably, the organic electroluminescent device comprises an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode arranged in sequence.

[0062] Generally speaking, an organic electroluminescent device (OLED) consists of a first electrode (anode), a second electrode (cathode), and an organic material layer located between the electrodes. This organic material layer can be 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.

[0063] In a specific embodiment, a substrate can be used below the first electrode or above the second electrode. The substrate is made of glass or a polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. In addition, the substrate used for the display can also be provided with thin film transistors (TFTs).

[0064] The first electrode can be formed by sputtering or depositing the material used as the first electrode on the substrate. When the first electrode serves as an anode, transparent conductive oxide materials such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO) and any combination thereof can be used. In addition, the anode material can also be selected from materials and combinations thereof that facilitate hole injection other than the listed anode materials, including materials known to be suitable for anodes. When the first electrode serves as a cathode, metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag) and any combination thereof can be used. In addition to the cathode materials listed above, the cathode material can also be a material and a combination thereof that facilitates electron injection, including materials known to be suitable for cathodes.

[0065] The organic material layer can be formed on the electrode by vacuum thermal evaporation, spin coating, printing and other methods. The compound used as the organic material layer can be an organic small molecule, an organic macromolecule and a polymer, and a combination thereof. The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a hole transport layer (HTL) with a single-layer structure, including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. The hole transport region can also be a multilayer structure including at least one layer of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0066] The material of the hole transport layer can be selected from, but 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 such as the compounds shown in HT-1 to HT-30 below, or any combination thereof.

[0067]

[0068] .

[0069] 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 use one or more compounds from the aforementioned HT-1 to HT-30, or one or more compounds from the following HI-1 to HI-3. Alternatively, one or more compounds from the aforementioned HT-1 to HT-30 can be doped with one or more compounds from the following HI-1 to HI-3:

[0070] .

[0071] The OLED organic material layer may also include an electron transport region between the light-emitting layer and the cathode. This region may be a single-layer electron transport layer (ETL), including those containing only one compound and those containing multiple compounds. The region may also be a multilayer structure comprising at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0072] The electron transport layer material may be selected from, but not limited to, one or a combination of at least two of the following ET-1 to ET-36:

[0073]

[0074]

[0075]

[0076] .

[0077] The device may further include an electron injection layer located between the electron transport layer and the cathode. Materials for the electron injection layer include, but are not limited to, one or more combinations of the following:

[0078] LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca.

[0079] Compared with the prior art, the present invention has the following beneficial effects:

[0080] The present invention generates an organometallic compound by changing the combination of substituents on 2-(dibenzo[b,d]furan-4-yl)pyridine to add -CN, -F, a branched alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted cycloalkyl group. This improves the intermolecular spatial configuration and has good spatial twisting ability, thereby avoiding carrier migration. When the organometallic compound is used as a specific doping material for the light-emitting layer and applied to an organic electroluminescent device, the driving voltage of the device is reduced, thereby avoiding carrier migration. The driving voltage is significantly reduced, and the luminous efficiency and life are significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of compound Z-1 prepared in Example 1. DETAILED DESCRIPTION

[0082] 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.

[0083] Example 1

[0084] This embodiment provides an organometallic compound Z-1, and the specific synthesis steps are as follows:

[0085]

[0086] Under nitrogen protection, 2,4-dichloro-3-hydroxybenzonitrile (200 mmol, CAS: 2383945-79-5) and anhydrous potassium carbonate (600 mmol) were placed in the reaction system, 1000 mL of toluene, 500 mL of anhydrous ethanol, and 500 mL of purified water were added, and Pd(PPh3)4 (1.5 mmol) was added under nitrogen protection. 2,3-dichlorophenylboronic acid (200 mmol, CAS: 151169-74- 3). After the addition was completed, the mixture was refluxed at 100°C for 24 h under nitrogen protection, then cooled to 25°C. After the reaction was cooled, the mixture 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, 400 g) to remove impurities. The developing solvent was EA (ethyl acetate): PE (petroleum ether) 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 1 (12.89 g, yield 21.7%).

[0087]

[0088] To a three-necked flask, intermediate 1 (30 mmol) and potassium carbonate (90 mmol) were added, and the nitrogen was replaced three times. DMF (N,N-dimethylformamide, 200 ml) was added to the system, and the nitrogen was replaced three times. The mixture was heated at 100 ° C. and refluxed for 24 h under a nitrogen atmosphere. Then, the mixture was cooled to room temperature and passed through a silica gel funnel. The organic phase was washed with saturated brine, extracted twice with ethyl acetate, dried over anhydrous magnesium sulfate, and concentrated by rotary evaporation. The crude product was purified by column chromatography and eluted with DCM (dichloromethane) / PE solution to obtain intermediate 2 (4.21 g, yield 33.2%).

[0089]

[0090] Under nitrogen protection, intermediate 2 (200 mmol) and anhydrous potassium carbonate (600 mmol) were placed in the reaction system, 1000 mL of toluene, 500 mL of anhydrous ethanol, and 500 mL of purified water were added. Pd(PPh3)4 (1.5 mmol) was added under nitrogen protection, and 4-methyl-2-pyridineboronic acid (200 mmol, CAS: 372963-48-9) 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. 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 column chromatography (200-300 mesh, 400 g) to remove impurities, the developing solvent EA:PE volume ratio = 1:16, the receiving solution was vortexed until no liquid flowed out, and vacuum dried to obtain the compound intermediate 3 (26.53 g, yield 41.7%).

[0091]

[0092] Under nitrogen protection, intermediate 3 (100 mmol) and anhydrous potassium carbonate (300 mmol) were placed in a reaction system. 500 mL of toluene, 250 mL of anhydrous ethanol, and 250 mL of purified water were added. Pd(PPh3)4 (0.75 mmol) was added under nitrogen protection, and (triphenylsilyl)boric acid (100 mmol, CAS: 2169240-95-1) 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, 300 g) to remove impurities. The developing solvent was DCM:PE (volume ratio = 1:3). The receiving solution was vortexed until no liquid flowed out and dried under vacuum to obtain the compound shown in Formula II-1 (48.58 g, yield 89.6%).

[0093]

[0094] Under a nitrogen protection system, ligand V-1 (50 mmol, CAS: 27012-22-2) and IrC13·3H2O (20 mmol) were weighed and placed in the reaction system. A mixed solution of 420 mL of ethylene glycol ethyl ether and 140 mL of purified water was added. The mixture was refluxed at 120°C for 36 hours under nitrogen protection, and then cooled to room temperature. A precipitate was precipitated, which was filtered, rinsed with water, anhydrous ethanol, and petroleum ether in sequence and dried to obtain a bridged ligand of formula IV-1 with a mass of 9.93 g and a yield of 88%.

[0095]

[0096] Under nitrogen protection, the intermediate formula IV-1 (20 mmol) was weighed, silver trifluoromethanesulfonate (44 mmol) was added, and then 600 mL of dichloromethane and 200 mL of methanol were added to the system. Under nitrogen protection, the mixture was refluxed at 25°C for 36 hours and cooled to room temperature. The column chromatography filtrate was concentrated until a solid precipitated to obtain an iridium complex formula III-1 (15.13 g, yield 95%).

[0097]

[0098] Under nitrogen protection, weigh III-1 (20 mmol), add formula II-1 (44 mmol), and then add 150 mL of anhydrous ethanol to the system. Reflux at 70 ° C for 36 hours under nitrogen protection, filter, wash with alcohol, and dry; use dichloromethane as solvent, use silica gel column chromatography, concentrate the filtrate and precipitate the solid to obtain the final compound Z-1 (11.26 g, yield 52.6%).

[0099] HPLC purity: greater than 99.5%;

[0100] MS (ESI, m / Z): [M+H]+: 1070.39.

[0101] The H NMR spectrum of compound Z-1 prepared in Example 1 is as follows: Figure 1 shown.

[0102] In addition, it should be noted that other compounds of the present invention can be obtained by referring to the synthesis methods of the above-mentioned embodiments, which are not described in detail here.

[0103] Device Example 1: Preparation of an organic electroluminescent device using an organometallic compound of formula Z-1

[0104] The ITO glass substrate with a coating thickness of 1500Å was washed twice in distilled water and ultrasonically washed for 30 minutes. After the distilled water washing was completed, it was ultrasonically washed in sequence with isopropyl alcohol, acetone, methanol and other solvents, and then dried. It was transferred to a plasma cleaning machine, washed for 10 minutes, and sent to a vapor deposition machine.

[0105] First, a 100Å-thick hole injection layer of HI-3 is evaporated on the ITO (anode), followed by a 900Å-thick hole transport layer of HT-3 evaporated on the hole injection layer, followed by a 400Å-thick light-emitting layer of a host material 4,4'-N,N'-dicarbazole biphenyl ("CBP") and a dopant material compound Z-1 in a 90:10 weight ratio, then a 400Å-thick electron transport layer of ET-3 is evaporated on the light-emitting layer, followed by a 150Å-thick electron injection layer material Liq evaporated on the electron transport layer, and finally a 1000Å-thick cathode material Al evaporated on the electron injection layer to obtain an organic electroluminescent device.

[0106] The structure of Liq is as follows:

[0107]

[0108] The performance and luminescence characteristics of the obtained devices were tested using a KEITHLEY 2400 source measurement unit and a CS-2000 spectroradiometer to evaluate the driving voltage, lifespan, and luminous efficiency.

[0109] Device Comparison Example 1:

[0110] An organic electroluminescent device was prepared in the same manner as in Device Example 1. The structure of the green light-emitting doping compound in the luminescent layer was as follows:

[0111] .

[0112] Device Comparison Example 2:

[0113] An organic electroluminescent device was prepared in the same manner as in Device Example 1. The structure of the green light-emitting doping compound in the luminescent layer was as follows:

[0114] .

[0115] Device Comparison Example 3:

[0116] An organic electroluminescent device was prepared in the same manner as in Device Example 1. The structure of the green light-emitting doping compound in the luminescent layer was as follows:

[0117] .

[0118] Device Comparison Example 4:

[0119] An organic electroluminescent device was prepared in the same manner as in Device Example 1. The structure of the green light-emitting doping compound in the luminescent layer was as follows:

[0120] .

[0121] Device Example 2-Device Example 30:

[0122] Referring to the method of the above-mentioned device embodiment 1, the only difference is that the doping material Z-1 is replaced by Z-7, Z-21, Z-56, Z-99, Z-143, Z-172, Z-205, Z-269, Z-310, Z-355, Z-412, Z-463, Z-502, Z-539, Z-578, Z-591, Z-605, Z-632, Z-666, Z-692, Z-715, Z-757, Z-785, Z-803, Z-845, Z-888, Z-918, Z-1023, and Z-1088 respectively.

[0123] 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 15,000 (nits). The test results are shown in Table 1.

[0124] Table 1

[0125]

[0126]

[0127] As can be seen from Table 1:

[0128] 1. By comparing Comparative Examples 1, 2, 3 and 4 with the organometallic compounds Z-1, Z-7, Z-21, Z-56, Z-99, Z-143, Z-172, Z-205, Z-269, Z-310, Z-355, Z-412, Z-463, Z-502, Z-539, Z-578, Z-591, Z-605, Z-632, Z-666, Z-692, Z-715, Z-757, Z-785, Z-803, Z-845, Z-888, Z-918, Z-1023 and Z-1088 of the present invention, it can be seen that the 2-(dibenzo[b,d]furan-4-yl)pyridine substituent The invention discloses a method for preparing an organic electroluminescent device by using a combination of -CN, -F, a branched alkyl group, a substituted or unsubstituted aryl group and a substituted or unsubstituted cycloalkyl group to generate an organometallic compound, increasing an electron-withdrawing group, improving the intermolecular spatial configuration, having good spatial torsion ability, and effectively adjusting the HOMO and LUMO energy levels, thereby avoiding carrier migration. When the method is used as a specific doping material for the light-emitting layer and applied to an organic electroluminescent device, the driving voltage of the device is reduced, thereby avoiding carrier migration. As a result, the organic electroluminescent device prepared by using the compound of the present application as a doping material for the light-emitting layer has a significantly lower driving voltage, and a significantly improved luminous efficiency and lifespan, compared with the organic electroluminescent device prepared in the comparative example.

[0129] 2. Compared with the organic electroluminescent devices prepared using the compounds provided in this application as the doping materials for the light-emitting layer in Comparative Examples 1-4, the driving voltage of the organic electroluminescent devices prepared using the compounds provided in this application as the doping materials for the light-emitting layer is significantly reduced and the luminous efficiency is significantly enhanced.

[0130] The applicant states that while the above-described embodiments illustrate the process of the present invention, the present invention is not limited to the above-described process steps, nor does it imply that the present invention must rely on the above-described process steps 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. An organometallic compound, characterized in that The organometallic compound has a structure shown in general formula I: ； wherein R1, R2, R3, R4, R5 and R6 are each independently selected from any one or a combination of at least two of hydrogen, -D, -CN, -F, -CF3, methyl, ethyl, propyl, butyl, pentyl, C1-C6 alkyl fully or partially substituted with deuterium, cyclopropyl, cyclopentyl, cyclohexyl, phenyl, phenyl substituted with pentyl, trimethylsilyl, and trimethylgermanium; R7, R8, R9, R 10 、R 11 、R 12 、R 13 and R 14 Each is independently selected from any one or a combination of at least two of hydrogen, -D, -CN, -F, -CF3, methyl, ethyl, propyl, butyl, pentyl, cyclopentyl, phenyl, deuterated phenyl, trimethylsilyl, trimethylgermanium, and a C1-C6 alkyl group which is fully or partially substituted with deuterium; Ra and Rb are present simultaneously; wherein the number of substitutions of Ra is 1-3, and Rb is independently selected from -CN or -F; Ra is selected from the following structures: ； R 15 、R 16 、R 17 、R 18 、R 19 、R 20 、R 21 、R 22 、R 23 、R 24 、R 25 、R 26 、R 27 、R 28 and R 29 Each is independently selected from any one or a combination of at least two of hydrogen, -F, -CN, -CD3, -CF3, -D, methyl, ethyl, propyl, butyl, pentyl, phenyl, deuterated ethyl, deuterated propyl, deuterated butyl, deuterated pentyl, biphenyl, C1-C6 alkyl-substituted phenyl, C1-C6 alkyl-substituted biphenyl, cyclopentyl, cyclopropyl, cyclohexyl, fluorine-substituted phenyl, cyano-substituted phenyl, deuterated benzene, trimethylgermanium, and trimethylsilyl; D stands for deuterium; The hydrogen atoms in Formula I are all substituted with deuterium, partially substituted with deuterium, or not substituted with deuterium.

2. An organometallic compound, characterized in that The organometallic compound is selected from one of the following compounds: ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； ； 。 3. An organic electroluminescent device, characterized in that: The organic electroluminescent device includes an anode, a cathode, and an organic material layer disposed between the anode and the cathode, wherein the organic material layer includes at least one of the organometallic compounds according to claim 1 or 2.

4. The organic electroluminescent device according to claim 3, characterized in that: The organic material layer includes a light-emitting layer, the light-emitting layer includes a host material and a doping material, and the doping material includes at least one of the organic metal compounds according to claim 1 or 2.

5. The organic electroluminescent device according to claim 4, characterized in that: The organic material layer further includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, an electron transport layer or an electron injection layer.

Images