An electroluminescent material and light-emitting device

Abstract

This invention relates to the field of organic electroluminescent display technology, specifically disclosing a novel organic electroluminescent material and an organic electroluminescent device prepared using this material. The organic electroluminescent material provided by this invention includes a first metal complex and a second metal complex, wherein the first metal complex and the second metal complex are independently selected from the structure shown in general formula (I), and the first metal complex and the second metal complex are different. By combining two different metal complexes, the first metal complex and the second metal complex, this invention obtains an emitting layer co-doped with multiple guest luminescent materials, which enables the prepared organic electroluminescent device to achieve lower voltage, higher luminous efficiency, and longer lifetime, significantly improving device performance.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescent display technology, and specifically discloses a novel organic electroluminescent material and an organic electroluminescent device prepared using the luminescent material. Background Technology

[0002] Organic electronic devices include, but are not limited to, the following types: organic light-emitting diodes (OLEDs), organic field-effect transistors (O-FETs), organic light-emitting transistors (OLETs), organic photovoltaic devices (COPVs), dye-sensitized solar cells (DSSCs), organic optical detectors, organic photosensors, organic field-effect devices (OFQDs), luminescent electrochemical cells (LEGS), organic laser diodes, and organic plasma light-emitting devices.

[0003] In 1987, Tang et al. from Eastman Kodak first reported a green electroluminescent device made of a double-layer organic thin film. The device used indium tin oxide (ITO) as the anode, on which a 75 nm thick amorphous, pinhole-free aromatic diamine film was deposited for hole transport. Then, a 60 nm thick 8-hydroxyquinoline aluminum film was deposited on the aromatic diamine film as both an electron transport layer and a light-emitting layer. A magnesium-silver alloy was used as the cathode. This double-layer film structure successfully reduced the turn-on voltage to 5.5 V and achieved high emissivity (>1000 cd·m⁻¹). -2 With a wavelength of 550 nm and an external quantum efficiency of 1.0%, it has great practical significance. In 1994, Kido et al. in Japan first fabricated an organic electroluminescent device that emits white light. They doped three fluorescent dyes of blue, green, and orange into a poly(N-vinylcarbazole) (PVK) film as a hole transport layer and emission layer, used a 1,2,4-triazole derivative (TAZ) as a hole blocking layer, and 8-hydroxyquinoline aluminum (Alq3) as an electron transport layer. The device was composed of a multilayer structure of glass substrate / ITO / PVK / TAZ / Alq3 / Mg:Ag. Under a driving voltage of 14V, they achieved a wide coverage of the visible light region and a brightness of up to 3400 cd·m. -2 The high-brightness white light emission is achieved by doping a polymer film with fluorescent compounds of various colors to form a single light-emitting layer. This discovery by Kido et al. adds a significant chapter to the application of organic electroluminescence, opens the door to the field of lighting for organic light-emitting devices, and promotes the further development of organic light-emitting devices.

[0004] Organic light-emitting devices emit light in two forms: fluorescence and phosphorescence. Fluorescence is emitted using the energy of singlet excitons, while phosphorescence is emitted using the energy of both singlet and triplet excitons. Because the ratio of singlet to triplet excitons is fixed at 1:3, theoretically, the internal quantum efficiency of fluorescent devices using only singlet excitons is at most 25%, while the internal quantum efficiency of phosphorescent devices can reach 100%.

[0005] Currently, organometallic complexes and organic electroluminescent devices with phosphorescence emission have been reported, but in many applications such as TVs and lighting equipment, the lifetime of OLEDs is insufficient, and higher efficiency OLEDs are still needed. Typically, the higher the brightness of an OLED, the shorter its lifetime. Therefore, for displays requiring long-term use and high resolution, OLEDs with high luminous efficiency and long lifetime are needed.

[0006] A large number of phosphorescent materials have been disclosed in the prior art. When these materials are applied to organic electroluminescent devices, some have long lifetimes and some have high external quantum efficiencies. However, they often cannot have both lifetime and efficiency at the same time. In practical applications, trade-offs need to be made according to the requirements.

[0007] To address the above problems, this invention, through in-depth research, aims to provide an organic electroluminescent device with improved overall performance. Summary of the Invention

[0008] The purpose of this invention is to develop a new organic electroluminescent material. By using a combination of two different metal complexes, a first metal complex and a second metal complex, a light-emitting layer co-doped with multiple guest light-emitting materials is obtained. This allows the organic electroluminescent device to achieve lower voltage, higher luminous efficiency, and longer lifetime, significantly improving the device's performance.

[0009] Specifically, in a first aspect, the present invention provides an electroluminescent material comprising a first metal complex and a second metal complex, wherein the first metal complex and the second metal complex are each independently selected from the structure shown in general formula (I), and the first metal complex and the second metal complex are not the same;

[0010]

[0011] in:

[0012] R 1 ~R 11 Each of the following is independently and arbitrarily selected from hydrogen atom, deuterium atom, alkyl, deuterated alkyl, alkoxy, alkylamino, alkylthio, fluorine atom, trifluoromethyl, aromatic and heterocyclic aromatic groups, and / or, R 1 ~R11 Adjacent substituents in the middle form a ring structure through bridging;

[0013] L is a monovalent bidentate anion ligand, wherein the bonding atoms X and Y are independently and arbitrarily selected from oxygen, nitrogen, and carbon atoms, respectively;

[0014] n is 1, 2, or 3.

[0015] In one embodiment of the present invention, L is phenylpyridinyl, substituted phenylpyridinyl, acetylacetonyl, or substituted acetylacetonyl.

[0016] Preferably, L is a group represented by formula L1 or formula L2:

[0017]

[0018] in:

[0019] In equation L1, R 12 ~R 19 Each of the following is independently and arbitrarily selected from hydrogen atom, deuterium atom, alkyl, deuterated alkyl, alkoxy, alkylamino, alkylthio, fluorine atom, trifluoromethyl, aromatic and heterocyclic aromatic groups, and / or, R 12 ~R 19 Adjacent substituents in the middle form a ring structure through bridging;

[0020] In equation L2, R 20 ~R 26 Each of the following is independently and arbitrarily selected from hydrogen atom, deuterium atom, alkyl, deuterated alkyl, alkoxy, alkylamino, alkylthio, fluorine atom, trifluoromethyl, aromatic and heterocyclic aromatic groups, and / or, R 20 ~R 26 Adjacent substituents are bridged to form a ring structure.

[0021] As a further preferred embodiment of the present invention, the first metal complex and the second metal complex are each independently selected from compounds represented by general formula I, general formula II or general formula III;

[0022]

[0023] Where m is 1 or 2.

[0024] More preferably, the first metal complex and the second metal complex are both selected from compounds represented by general formula I, or both selected from compounds represented by general formula II, or both selected from compounds represented by general formula III, and the first metal complex and the second metal complex are different.

[0025] As one embodiment of the present invention, the substituents involved in general formulas I, II, and III are defined as follows:

[0026] The R 1 ~R 11 Each of the following is independently and arbitrarily selected from hydrogen atoms, deuterium atoms, C1-C5 alkyl groups, C1-C5 deuterated alkyl groups, alkoxy groups containing 1-5 carbon atoms, alkylamino groups containing 1-5 carbon atoms, alkathioyl groups containing 1-5 carbon atoms, fluorine atoms, trifluoromethyl groups, phenyl groups, substituted phenyl groups, heterocyclic aromatic groups; and / or, R 1 ~R 11 Adjacent substituents are bridged to form a fused ring structure, wherein the fused ring structure is any one of a substituted or unsubstituted five-membered ring, a substituted or unsubstituted six-membered ring, a substituted or unsubstituted five-membered heterocycle, and a substituted or unsubstituted six-membered heterocycle. The substituents used for substitution are C1 to C5 alkyl, phenyl, benzo[a], substituted phenyl, or substituted benzo[a], and the five-membered or six-membered heterocycle contains at least one heteroatom, which is arbitrarily selected from oxygen, sulfur, nitrogen, and selenium atoms.

[0027] The R 12 ~R 19 Each of the following is independently and arbitrarily selected from hydrogen atom, deuterium atom, C1-C5 alkyl group, C1-C5 deuterated alkyl group, fluorine atom, phenyl, substituted phenyl, alkoxy group containing 1-5 carbon atoms, alkylamino group containing 1-5 carbon atoms, alkylthio group containing 1-5 carbon atoms, trifluoromethyl group, heterocyclic aromatic group; and / or, R 12 ~R 19 Adjacent substituents are bridged to form a fused ring structure, wherein the fused ring structure is any one of a substituted or unsubstituted five-membered ring, a substituted or unsubstituted six-membered ring, a substituted or unsubstituted five-membered heterocycle, and a substituted or unsubstituted six-membered heterocycle. The substituents used for substitution are C1 to C5 alkyl, phenyl, benzo[a], pyrido[a], alkyl-substituted pyrido[a], or deuterated alkyl-substituted pyrido[a]. The five-membered or six-membered heterocycle contains at least one heteroatom, which is arbitrarily selected from oxygen, sulfur, and nitrogen atoms.

[0028] The R 20 ~R 26 Each of the following is independently and arbitrarily selected from hydrogen atoms, deuterium atoms, C1-C5 alkyl groups, fluorine atoms, C1-C5 deuterated alkyl groups, alkoxy groups containing 1-5 carbon atoms, alkylamino groups containing 1-5 carbon atoms, alkylthio groups containing 1-5 carbon atoms, and trifluoromethyl groups.

[0029] Preferably, the R 1 ~R 11 Each of the following is independently and arbitrarily selected from hydrogen atom, deuterium atom, C1-C5 alkyl group, C1-C5 deuterated alkyl group, phenyl group, C1-C5 alkyl-substituted phenyl group, fluorine atom, pyridyl group; and / or, R 1 ~R11 Adjacent substituents are bridged to form a fused ring structure, wherein the fused ring structure is any one of a substituted or unsubstituted five-membered ring, a substituted or unsubstituted benzene ring, or a substituted or unsubstituted five-membered heterocycle. The substituents used for substitution are C1-C5 alkyl, phenyl, benzo[a], C1-C5 alkyl-substituted benzo[a], or C1-C5 deuterated alkyl-substituted benzo[a], wherein the five-membered heterocycle has at least one heteroatom, which is arbitrarily selected from oxygen, sulfur, and selenium atoms.

[0030] The R 12 ~R 19 Each of the following is independently and arbitrarily selected from hydrogen atoms, deuterium atoms, C1-C5 alkyl groups, C1-C5 deuterated alkyl groups, fluorine atoms, phenyl groups; and / or, R 12 ~R 19 Adjacent substituents are bridged to form a fused ring structure, wherein the fused ring structure is any one of a substituted or unsubstituted benzene ring or a substituted or unsubstituted five-membered heterocycle. The substituents used for substitution are C1 to C5 alkyl, phenyl, benzo[a], pyrid[a], alkyl-substituted pyrid[a] containing 1 to 5 carbon atoms, or deuterated alkyl-substituted pyrid[a] containing 1 to 5 carbon atoms. The five-membered heterocycle has at least one heteroatom, which is arbitrarily selected from oxygen atoms and sulfur atoms.

[0031] The R 20 ~R 26 Each of the following is independently and arbitrarily selected from hydrogen atoms, deuterium atoms, and C1 to C5 alkyl groups.

[0032] In this application, the C1 to C5 alkyl groups can be straight-chain alkyl groups or branched alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, isobutyl, pentyl, neopentyl, etc.

[0033] C1-C5 deuterated alkyl groups are C1-C5 alkyl groups in which some hydrogen atoms are replaced by deuterium. Similarly, C1-C5 alkyl groups can be straight-chain alkyl groups or branched alkyl groups. Examples of C1-C5 deuterated alkyl groups include deuterated methyl, deuterated isopropyl, deuterated pentyl, deuterated neopentyl, and deuterated tert-butyl.

[0034] Alkoxy groups containing 1 to 5 carbon atoms are C n H 2n+1 The group represented by O-, where n is 1 to 5. Alkoxy groups containing 1 to 5 carbon atoms can be methoxy, ethoxy, etc.

[0035] When adjacent substituents are bridged to form a ring structure, for example, R 1 ~R 11When adjacent substituents are bridged to form a fused ring structure, the fused ring structure can be any one of a substituted or unsubstituted five-membered ring, a substituted or unsubstituted six-membered ring, a substituted or unsubstituted five-membered heterocycle, and a substituted or unsubstituted six-membered heterocycle. The five-membered or six-membered heterocycle contains at least one heteroatom, which is arbitrarily selected from oxygen, sulfur, nitrogen, and selenium atoms. For example, the fused ring structure can be a benzo[a] ring, a furan[a] ring, a thiophene[a] ring, a Se-heterocyclic pentenene[a] ring, etc. The fused ring structure can be further substituted by substituents, such as benzo[a] group, alkyl group, alkyl-substituted benzo[a] group (e.g., methyl-substituted benzo[a] group, ethyl-substituted benzo[a] group, propyl-substituted benzo[a] group), deuterated alkyl-substituted benzo[a] group (e.g., deuterated methyl-substituted benzo[a] group, deuterated propyl-substituted benzo[a] group, etc.

[0036] In a preferred embodiment of the present invention, the first metal complex and the second metal complex are each independently selected from compounds shown in the following structural formulas, and the first metal complex and the second metal complex are not the same.

[0037]

[0038]

[0039]

[0040]

[0041]

[0042] More preferably, the first metal complex and the second metal complex are each independently selected from compounds shown in I-1 to I-16, and the first metal complex and the second metal complex are different; or, the first metal complex and the second metal complex are each independently selected from compounds shown in II-1 to II-44, and the first metal complex and the second metal complex are different; or, the first metal complex and the second metal complex are each independently selected from compounds shown in III-1 to III-64, and the first metal complex and the second metal complex are different.

[0043] As one embodiment of the present invention, the organic electroluminescent material provided by the present invention has a mixing mass ratio of the first metal complex and the second metal complex between 1:99 and 99:1.

[0044] Preferably, in the organic electroluminescent material provided by the present invention, the mixing mass ratio of the first metal complex and the second metal complex is between 1:4 and 5:1.

[0045] More preferably, in the organic electroluminescent material provided by the present invention, the mixing mass ratio of the first metal complex and the second metal complex is between 1:4 and 4:1, more preferably 1:1.

[0046] Secondly, the present invention also provides the application of the organic electroluminescent material in the preparation of organic electroluminescent devices.

[0047] Preferably, the organic electroluminescent material is used as a dopant material for the light-emitting layer in an organic electroluminescent device.

[0048] More preferably, the organic electroluminescent material accounts for 1% to 20% of the total mass of the light-emitting layer, even more preferably 1% to 10%, and more preferably 5% to 10%.

[0049] Thirdly, the present invention also provides an organic electroluminescent device comprising the aforementioned organic electroluminescent material, the device comprising:

[0050] anode,

[0051] cathode,

[0052] And an organic layer disposed between the anode and the cathode, wherein the organic layer includes a light-emitting layer, and the light-emitting layer includes the organic electroluminescent material of the present invention.

[0053] Preferably, the light-emitting layer comprises a host material and a light-emitting material, wherein the light-emitting material comprises the organic electroluminescent material described in this invention.

[0054] More preferably, the doping concentration of the organic electroluminescent material in the light-emitting layer is 1-20%, even more preferably 1-10%, and more preferably 5-10%.

[0055] Preferably, the host material of the light-emitting layer contains at least one chemical group selected from the following: benzene, pyridine, pyrimidine, triazine, carbazole, azacarbazole, indolecarbazole, dibenzothiophene, azadibenzothiophene, dibenzofuran, azadibenzofuran, dibenzoselenene, triphenylene, azatriphenylene, fluorene, silylfluorene, naphthalene, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene, azaphenanthrene, and combinations thereof.

[0056] Preferably, the organic electroluminescent device emits green or yellow light.

[0057] Fourthly, the present invention also provides a display component, including the organic electroluminescent device described in the present invention.

[0058] This invention provides a novel organic electroluminescent device in which the light-emitting layer is co-doped with multiple guest light-emitting materials. By using a combination of two different metal complexes, a first metal complex and a second metal complex, the resulting organic electroluminescent device can achieve lower voltage, higher luminous efficiency, and longer lifespan, thus significantly improving the device's performance. Detailed Implementation

[0059] The technical solution of the present invention will be described in detail below.

[0060] OLEDs can be fabricated on various substrates, such as glass, plastic, and metal. An OLED has multiple layers, including a substrate, an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode. It can be fabricated by sequentially depositing the described layers. The properties and functions of each layer, as well as exemplary materials, are described in more detail in columns 6-10 of U.S. Patent 7,279,704B2, the entire contents of which are incorporated herein by reference.

[0061] Each of these layers has numerous examples. For instance, a flexible and transparent substrate-anode combination is disclosed in U.S. Patent No. 5,844,363, which is incorporated herein by reference in its entirety. An example of a p-doped hole transport layer is m-MTDATA doped with F4-TCNQ at a molar ratio of 50:1, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated herein by reference in its entirety. An example of a host material is disclosed in U.S. Patent No. 6,303,238 to Thompson et al., which is incorporated herein by reference in its entirety. An example of an n-doped electron transport layer is BPhen doped with Li at a molar ratio of 1:1, as disclosed in U.S. Patent Application Publication No. 2003 / 0230980, which is incorporated herein by reference in its entirety. Examples of cathodes are disclosed in U.S. Patent Nos. 5,703,436 and 5,707,745, which are incorporated herein by reference in their entirety. These cathodes comprise composite cathodes having a thin metal layer, such as Mg:Ag, overlaid with a transparent, conductive, sputter-deposited ITO layer. The principles and use of barrier layers are described in more detail in U.S. Patent No. 6,097,147 and U.S. Patent Application Publication No. 2003 / 0230980, which are also incorporated herein by reference in their entirety. Examples of implantation layers are provided in U.S. Patent Application Publication No. 2004 / 0174H6, which is incorporated herein by reference in its entirety. A description of protective layers can be found in U.S. Patent Application Publication No. 2004 / 0174H6, which is incorporated herein by reference in its entirety.

[0062] The functionality of an OLED can be achieved by combining the various layers described above, or by omitting some layers entirely. It may also include other layers not explicitly described.

[0063] Devices manufactured according to embodiments of the present invention can be incorporated into a variety of consumer products having one or more electronic component modules (or units). Some examples of such consumer products include flat panel displays, monitors, medical monitors, televisions, billboards, lights for indoor or outdoor lighting and / or signaling, head-up displays, fully or partially transparent displays, flexible displays, smartphones, tablet computers, phablets, wearable devices, smartwatches, laptop computers, digital cameras, portable camcorders, viewfinders, microdisplays, 3D displays, vehicle displays, and taillights.

[0064] The materials and structures described in this article can also be used in other organic electronic devices listed above.

[0065] The specific materials described in this invention for use in organic light-emitting devices can be used in combination with a variety of other materials present in the device. These combinations of materials are described in detail in paragraphs 0132-0161 of U.S. Patent Application US2016 / 0359122A1, the entire contents of which are incorporated herein by reference. The materials described or mentioned herein are non-limiting examples of materials that can be used in combination with the compounds disclosed herein, and those skilled in the art can readily consult the literature to identify other materials that can be used in combination.

[0066] Materials described herein for use in specific layers in organic light-emitting devices can be used in combination with a variety of other materials present in said devices. For example, the compounds disclosed herein can be used in combination with a variety of host layers, delivery layers, barrier layers, injection layers, electrodes, and other possible layers. These combinations of materials are described in detail in paragraphs 0080-0101 of U.S. Patent Application US2015 / 0349273A1, the entire contents of which are incorporated herein by reference. The materials described or mentioned herein are non-limiting examples of materials that can be used in combination with the compounds disclosed herein, and those skilled in the art can readily consult the literature to identify other materials that can be used in combination.

[0067] In the examples of material synthesis, unless otherwise stated, all reactions were carried out under nitrogen protection. All reaction solvents were anhydrous and used as is from commercial sources. The synthesized products were structurally confirmed and characterized using one or more instruments conventional in the art (including but not limited to Agilent liquid chromatographs, liquid chromatography-mass spectrometers, gas chromatography-mass spectrometers, differential scanning calorimeters, fluorescence spectrophotometers, electrochemical workstations, sublimation apparatuses, etc.) in methods well known to those skilled in the art. In the examples of devices, the fabrication and testing of the devices were also performed using equipment conventional in the art (including but not limited to vapor deposition machines manufactured by Nanjing Institute of Microelectronics, optical testing systems and lifetime testing systems manufactured by Suzhou Fushida, ellipsometers manufactured by Wuhan Yiguang Technology, etc.) in methods well known to those skilled in the art. Since those skilled in the art are familiar with the use of the above-mentioned equipment, testing methods, and other related content, and can obtain the inherent data of the samples definitively and unaffected, the above-mentioned related content will not be elaborated further in this patent.

[0068] The technical solution of the present invention will be further described below through specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Any equivalent changes or modifications made without departing from the spirit of the invention should be included within the scope of the claims.

[0069] The preparation methods of the first and second metal complexes selected in this invention are not limited. Typical but not limited examples are the following compounds, and their synthetic routes and preparation methods are as follows.

[0070] Example 1: Synthesis of Compound III-5

[0071]

[0072] The reaction formula is as follows:

[0073]

[0074] The specific experimental steps are as follows:

[0075] (1) In a 500 mL three-necked flask equipped with a mechanical stirrer, reflux condenser, and nitrogen protection device, the following were added sequentially: ligand P1 (25 mmol, 8.3 g), iridium trichloride trihydrate (10 mmol, 3.52 g), ethylene glycol monoethyl ether (90 mL), and distilled water (30 mL). The system was evacuated and purged with nitrogen (N2) five times to remove oxygen. The mixture was then refluxed at 110 °C for 24 hours. After natural cooling, 10 mL of distilled water was added, the mixture was shaken, filtered, washed with water, and washed with ethanol. The mixture was then dried under vacuum to obtain 6.6 g of crude dichlorobridged intermediate M7, a yellow solid, with a yield of 74.2%.

[0076] (2) In a 250 mL three-necked flask equipped with a magnetic stirrer and a reflux condenser, the above intermediate M7 (5 mmol, 8.9 g), acetylacetone (25 mmol, 2.5 g, 2.6 mL), anhydrous Na2CO3 (22 mmol, 2.3 g), and 100 mL of ethylene glycol monoethyl ether were added sequentially. The system was evacuated and purged with N2, repeated five times to remove oxygen. The mixture was then heated under N2 protection in an oil bath at 120 °C for reflux for 24 hours. After natural cooling to room temperature, the mixture was filtered, washed sequentially with water, n-hexane, and diethyl ether, and dried to obtain a yellow crude product. After dissolving in CH2Cl2 and separating by column chromatography, the solvent was removed by removing the CH2Cl2 eluent and drying to obtain 7.46 g of yellow powder, with a yield of 78.2%.

[0077] Product MS (m / e): 954.12; Elemental analysis (C) 43 H 29 IrN4O6S2): Theoretical values: C: 54.08%, H: 3.04%, N: 5.87%; Measured values: C: 54.21%, H: 3.16%, N: 5.79%.

[0078] Example 2: Synthesis of Compound III-1

[0079]

[0080] The specific experimental steps are the same as in Example 1. The difference is that in step (2), 3,7-diethylnonane-4,6-dione is used instead of acetylacetone to react with intermediate M7. Other raw materials and steps are the same as in Example 1. Compound III-1 is prepared with a yield of 72.8%.

[0081] Product MS (m / e): 1066.38; Elemental analysis (C) 51 H 45 IrN4O6S2): Theoretical values: C: 57.45%, H: 4.25%, N: 5.25%; Measured values: C: 57.52%, H: 4.33%, N: 5.16%.

[0082] Example 3: Synthesis of Compound I-1

[0083]

[0084] The reaction formula is as follows:

[0085]

[0086] The specific experimental steps were as follows: In a 250 mL three-necked flask equipped with a magnetic stirrer and a reflux condenser, Ir(acac)3 (10 mmol, 4.9 g), ligand P1 (40 mmol, 13.3 g), and 150 mL of glycerol were added sequentially. The system was evacuated and purged with N2, repeated five times to remove oxygen. The mixture was then heated under N2 protection in an oil bath at 190 °C for reflux for 24 hours. After natural cooling to room temperature, the mixture was filtered, washed sequentially with water, n-hexane, and diethyl ether, and dried to obtain a yellow crude product. After dissolving in CH2Cl2, column chromatography was performed, with CH2Cl2 as the eluent. The solvent was then removed by vacuum drying to obtain 5.4 g of yellow powder, with a yield of 45.5%.

[0087] Product MS (m / e): 1186; Elemental analysis (C) 57 H 33 IrN6S3O6): Theoretical values: C: 57.67%, H: 2.78%, N: 7.08%; Measured values: C: 57.58%, H: 2.91%, N: 7.14%.

[0088] Example 4: Synthesis of Compound II-21

[0089]

[0090] The reaction formula is as follows:

[0091]

[0092] The specific experimental steps are as follows:

[0093] (1) In a 100 mL three-necked flask equipped with a mechanical stirrer, reflux condenser, and nitrogen protection device, phenylpyridine (15 mmol, 2.5 mL), iridium trichloride trihydrate (6 mmol, 2.1 g), ethylene glycol monoethyl ether (45 mL), and distilled water (15 mL) were added sequentially. The system was evacuated and purged with nitrogen (N2) five times to remove oxygen. The mixture was then refluxed at 110 °C for 24 hours. After natural cooling, 10 mL of distilled water was added, the mixture was shaken, filtered, washed with water, and washed with ethanol. The mixture was then dried under vacuum to obtain 2.7 g of crude dichlorobridged intermediate M8, a yellow solid, with a yield of 84.4%.

[0094] (2) In a 500 mL three-necked flask equipped with a nitrogen protection device, dichloro-bridging intermediate M8 (10.7 g, 10 mmol) was added sequentially, followed by 150 mL of dichloromethane. The mixture was stirred thoroughly, and then 200 mL of a methanol solution of silver trifluoromethanesulfonate (6.4 g, 25 mmol) was added. The mixture was stirred for 24 hours in the dark. After cooling to room temperature, the generated AgCl was filtered off using diatomaceous earth. The filtrate was evaporated to dryness to obtain a light yellow solid powder. This solid was used directly in the next reaction without further treatment.

[0095] (3) In a 250 ml three-necked flask, add the yellowish-brown solid (5.1 g, 6.9 mmol) and ligand P1 (5.05 g, 15.2 mmol) obtained in step (2) above, then add 100 ml of ethanol, heat the mixture under reflux for 36 hours, cool the reaction mixture to room temperature, filter the resulting yellow solid, dissolve the solid in dichloromethane, separate by column chromatography, and obtain 3.2 g of bright yellow solid. The two-step yield is 53.3%.

[0096] Product MS (m / e): 864; Elemental analysis (C) 41 H 27 IrN4SO2): Theoretical values: C: 56.94%, H: 3.13%, N: 6.48%; Measured values: C: 56.88%, H: 3.25%, N: 6.63%.

[0097] Following the above synthesis method, or referring to patent CN112341499B, other compounds, such as compounds III-25, I-7, and II-17, were synthesized.

[0098] Those skilled in the art should understand that the above preparation method is merely an exemplary example, and they can obtain other compound structures of the present invention by improving it.

[0099] Examples 5-13: Organic Electroluminescent Materials

[0100] Examples 5-13 below provide organic electroluminescent materials with different compositions. The specific compositions of each example are shown in Table 1 below.

[0101] Table 1 Organic Electroluminescent Materials

[0102]

[0103] Device Examples

[0104] Organic electroluminescent devices were prepared using the organic electroluminescent materials provided in Examples 5-13.

[0105] This invention does not specifically limit the fabrication method of organic electroluminescent devices. The preparation methods in the following embodiments are merely examples and should not be construed as limiting. Those skilled in the art can make reasonable improvements to the preparation methods of the following embodiments based on existing technology.

[0106] Device Example 1

[0107] This embodiment provides an organic electroluminescent device, the fabrication process of which is as follows:

[0108] First, the glass substrate, which has a 120 nm thick indium tin oxide (ITO) anode, is cleaned using UV ozone and oxygen plasma treatment. After treatment, the substrate is dried in a nitrogen-filled glove box to remove moisture. Then, the substrate is mounted on a substrate holder and placed in a vacuum chamber. Next, an organic layer is deposited on the substrate. The organic layer specified below is deposited at a vacuum degree of approximately 10... -8 Under Torr conditions The deposition rate is achieved by sequentially vaporizing the ITO anode under thermal vacuum, as detailed below:

[0109] Simultaneously, the vapor-deposited compounds HT and NDP-9 are used as the hole injection layer (HIL), with a thickness of [missing information]. Compound HT accounts for 98% of the total mass of the hole injection layer, and NDP-9 accounts for 2% of the total mass of the hole injection layer.

[0110] Compound HT is used as a hole transport layer (HTL) with a thickness of [missing information].

[0111] The compound TAPC is used as an electron blocking layer (EBL) with a thickness of [missing information].

[0112] An emissive layer (EML) was deposited by vapor deposition. The main material of the emissive layer was DIC-TRZ, and the emissive material was the organic electroluminescent material provided in Example 5. The emissive layer (EML) was obtained by co-evaporation and had a thickness of [missing information]. The specific mass percentages of the main compound DIC-TRZ and the organic electroluminescent material in the light-emitting layer are shown in Table 2. The temperature difference between the first metal complex and the second metal complex during device fabrication should be less than 15°C, preferably less than 5°C.

[0113] The compound TPBI was used as the hole blocking layer (HBL), with a thickness of [missing information].

[0114] On the hole-blocking layer, compound ET01 and 8-hydroxyquinoline-lithium (Liq) were co-deposited as an electron transport layer (ETL) with a thickness of [missing information]. Compounds ET01 and Liq each account for 50% of the total weight of the electron transport layer;

[0115] Finally, vapor deposition A thick layer of LiF is used as the electron injection layer (EIL) and is deposited by evaporation. Aluminum is used as the cathode.

[0116] The device was then transferred back to the glove box and sealed with a glass cover to complete the device, resulting in Device Example 1.

[0117] Device Examples 2-9

[0118] Device Examples 2-9 were fabricated following Device Example 1, with the only difference being that the organic electroluminescent material provided in Examples 6-13 was selected as the luminescent material in the fabrication of the emissive layer (EML), and co-deposited with the host material DIC-TRZ to obtain the emissive layer (EML) with a thickness of [thickness missing]. The specific mass percentages of the host compound DIC-TRZ and organic electroluminescent materials in the luminescent layer are shown in Table 2.

[0119] Device Comparison Examples

[0120] The following are further examples of device comparisons:

[0121] Comparative Device Example 1 was prepared in accordance with Device Example 1, except that in the light-emitting layer (EML), both the first metal complex and the second metal complex in the light-emitting material are III-5.

[0122] Comparative Example 2 was fabricated in accordance with Device Example 1, except that in the light-emitting layer (EML), both the first metal complex and the second metal complex in the light-emitting material are I-1.

[0123] Comparative Example 3 was prepared in accordance with Device Example 1, except that in the light-emitting layer (EML), both the first metal complex and the second metal complex in the light-emitting material are II-21.

[0124] The detailed device layer structures and thicknesses of the above device embodiments and comparative examples are shown in Table 2 below. The materials used are not a single type, but rather different compounds doped together in the weight ratios listed in Table 2.

[0125] Table 2 Device structures of device embodiments and comparative examples

[0126]

[0127]

[0128] The material structure used in the above devices is shown below:

[0129]

[0130]

[0131] The performance of the devices prepared above in the examples and comparative examples was tested. Table 3 lists the performance at 20 mA / cm². 2 Under the specified conditions, the voltage (V), current efficiency (CE), and device lifetime (LT) of devices in Examples 1-9 and Comparative Examples 1-3 were measured. 97 ) Test results.

[0132] Table 3 Device Performance Test Data

[0133]

[0134] Based on the test data of the above devices, we can find that compared with Comparative Examples 1 to 3, the devices in Examples 1 to 9, i.e., the light-emitting layer is co-doped with multiple guest light-emitting materials compared with the use of a single light-emitting material, show significant improvements in voltage, current efficiency, and lifetime when using two metal complexes as dopants. The resulting organic electroluminescent devices can achieve lower voltage, higher luminous efficiency, and longer lifetime, significantly improving device performance and bringing unexpected benefits to device performance.

[0135] As can be seen from the device data in Examples 1-3, changing the proportion of the two metal complex dopants in the total weight of the light-emitting layer and the mass ratio of the two metal complex dopants significantly alters the device performance. When the mass ratio of the two metal complex dopants is 1:1 and the two metal complex dopants account for 6% of the total weight of the light-emitting layer, the device exhibits the lowest voltage, the highest current efficiency, and the longest lifetime.

[0136] Comparing the detection data of Examples 1, 4-7, 8, and 9, it can be seen that the more similar the compound structures of the two metal complex dopants are, the better the performance of the device prepared using them as the light-emitting layer doping material. In particular, Example 7 shows a significant improvement in current efficiency and an unexpectedly improved lifetime.

[0137] In summary, the present invention, through the combination of a first metal complex and a second metal complex, exhibits excellent overall device performance in the device due to the good energy matching between the two compounds, resulting in lower driving voltage, higher efficiency, and ultra-long device life.

[0138] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. An electroluminescent material, characterized in that, It includes a first metal complex and a second metal complex, wherein the first metal complex and the second metal complex are both selected from compounds represented by general formula I, or both selected from compounds represented by general formula II, or both selected from compounds represented by general formula III, and the first metal complex and the second metal complex are different; ； Where m is 1 or 2; The R 1 ~R 11 Each of the following is independently and arbitrarily selected from hydrogen atom, deuterium atom, C1-C5 alkyl group, C1-C5 deuterated alkyl group, phenyl group, C1-C5 alkyl-substituted phenyl group, fluorine atom, pyridyl group; and / or, R 1 ~R 11 Adjacent substituents are bridged to form a fused ring structure, wherein the fused ring structure is any one of a substituted or unsubstituted five-membered ring, a substituted or unsubstituted benzene ring, or a substituted or unsubstituted five-membered heterocycle. The substituents used for substitution are C1-C5 alkyl, phenyl, benzo[a], C1-C5 alkyl-substituted benzo[a], or C1-C5 deuterated alkyl-substituted benzo[a], wherein the five-membered heterocycle has at least one heteroatom, which is arbitrarily selected from oxygen, sulfur, and selenium atoms. The R 12 ~R 19 Each of the following is independently and arbitrarily selected from hydrogen atoms, deuterium atoms, C1-C5 alkyl groups, C1-C5 deuterated alkyl groups, fluorine atoms, phenyl groups; and / or, R 12 ~R 19 Adjacent substituents are bridged to form a fused ring structure, wherein the fused ring structure is any one of a substituted or unsubstituted benzene ring or a substituted or unsubstituted five-membered heterocycle. The substituents used for substitution are C1 to C5 alkyl, phenyl, benzo[a], pyrid[a], alkyl-substituted pyrid[a] containing 1 to 5 carbon atoms, or deuterated alkyl-substituted pyrid[a] containing 1 to 5 carbon atoms. The five-membered heterocycle has at least one heteroatom, which is arbitrarily selected from oxygen atoms and sulfur atoms. The R 20 ~R 26 Each of the following is independently and arbitrarily selected from hydrogen atoms, deuterium atoms, and C1 to C5 alkyl groups.

2. The luminescent material according to claim 1, characterized in that, The first metal complex and the second metal complex are each independently selected from the compounds shown in the following structural formulas, and the first metal complex and the second metal complex are not the same; 。 3. The electroluminescent material according to claim 1, characterized in that, The first metal complex and the second metal complex are independently selected from the compounds shown in I-1 to I-16, and the first metal complex and the second metal complex are different. Alternatively, the first metal complex and the second metal complex are each independently selected from the compounds shown in II-1 to II-44, and the first metal complex and the second metal complex are not the same; Alternatively, the first metal complex and the second metal complex are independently selected from the compounds shown in III-1 to III-64, and the first metal complex and the second metal complex are not the same.

4. The luminescent material according to claim 1, characterized in that, The mass ratio of the first metal complex to the second metal complex is between 1:99 and 99:

1.

5. The luminescent material according to claim 1, characterized in that, The mass ratio of the first metal complex to the second metal complex is between 1:4 and 5:

1.

6. The luminescent material according to claim 1, characterized in that, The mass ratio of the first metal complex to the second metal complex is between 1:4 and 4:

1.

7. The use of the luminescent material according to any one of claims 1 to 6 in the preparation of organic electroluminescent devices.

8. The application according to claim 7, characterized in that, The luminescent material is used as a dopant material for the luminescent layer in organic electroluminescent devices; and / or, The luminescent material accounts for 1% to 20% of the total mass of the luminescent layer.

9. The application according to claim 7, characterized in that, The luminescent material accounts for 1% to 10% of the total mass of the luminescent layer.

10. The application according to claim 7, characterized in that, The luminescent material accounts for 5% to 10% of the total mass of the luminescent layer.

11. An organic electroluminescent device comprising the luminescent material according to any one of claims 1 to 6, characterized in that, include: anode, cathode, And an organic layer disposed between the anode and the cathode, wherein the organic layer includes a light-emitting layer, and the light-emitting layer includes the light-emitting material according to any one of claims 1 to 6.

12. The organic electroluminescent device according to claim 11, characterized in that, The light-emitting layer includes the host material and the light-emitting material.

13. The organic electroluminescent device according to claim 11, characterized in that, The doping concentration of the luminescent material in the luminescent layer is 1 to 20% of the total mass of the luminescent layer.

14. The organic electroluminescent device according to claim 11, characterized in that, The doping concentration of the luminescent material in the luminescent layer is 1 to 10% of the total mass of the luminescent layer.

15. The organic electroluminescent device according to claim 11, characterized in that, The doping concentration of the luminescent material in the luminescent layer is 5 to 10% of the total mass of the luminescent layer.

16. The organic electroluminescent device according to claim 12, characterized in that, The main material comprises at least one chemical group selected from the following: benzene, pyridine, pyrimidine, triazine, carbazole, azacarbazole, indolecarbazole, dibenzothiophene, azadibenzothiophene, dibenzofuran, azadibenzofuran, dibenzoselenene, triphenylene, azatriphenylene, fluorene, silylfluorene, naphthalene, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene, azaphenanthrene, and combinations thereof.

17. A display component, characterized in that, The organic electroluminescent device included in any one of claims 11-16.

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