CN115895642A

CN115895642A - Organic electroluminescent material and luminescent device

Info

Publication number: CN115895642A
Application number: CN202211206381.XA
Authority: CN
Inventors: 曹占广; 呼建军; 陈婷; 石志亮; 李小赢; 班全志; 杭德余
Original assignee: Beijing Yanhua Jilian Optoelectronic Technology Co ltd
Current assignee: Beijing Yanhua Jilian Optoelectronic Technology Co ltd
Priority date: 2022-09-30
Filing date: 2022-09-30
Publication date: 2023-04-04

Abstract

The invention relates to the technical field of organic electroluminescent display, and particularly discloses a novel organic electroluminescent material and an organic electroluminescent device prepared from the same. The organic electroluminescent material provided by the invention comprises a first compound and a second compound, wherein the first compound and the second compound are respectively and independently selected from structures shown in a general formula (I), and the first compound and the second compound are different. The invention obtains the light-emitting layer which is jointly doped with a plurality of guest light-emitting materials by combining two different metal complexes of the first compound and the second compound, so that the prepared organic electroluminescent device can obtain lower voltage, higher light-emitting efficiency and longer service life, and the performance of the device can be obviously improved.

Description

Organic electroluminescent material and luminescent device

Technical Field

The invention relates to the technical field of organic electroluminescent display, and particularly discloses a novel organic electroluminescent material and an organic electroluminescent device prepared by adopting the novel organic electroluminescent material.

Background

Organic electronic devices include, but are not limited to, the following classes: organic Light Emitting Diodes (OLEDs), organic field effect transistors (O-FETs), organic Light Emitting Transistors (OLETs), organic photovoltaics (COPVs), dye-sensitized solar cells (DSSCs), organic optical detectors, organic photoreceptors, organic field effect devices (OFQDs), light emitting electrochemical cells (LEGS), organic laser diodes, and organic plasma light emitting devices.

In 1987, tang et al of Ishmann kodak company in USA reported a green electroluminescent device made of a double-layer organic film for the first time, the device uses Indium Tin Oxide (ITO) as an anode, an amorphous aromatic diamine film without pinholes and with a thickness of 75nm is evaporated on the anode for hole transmission, then an 8-hydroxyquinoline aluminum film with a thickness of 60nm is further coated on the aromatic diamine film for an electron transmission layer and a light emitting layer, and a magnesium-silver alloy is used as a cathode, the double-layer film structure successfully reduces the starting voltage to 5.5V, and high-radiation luminescence is realized (high-radiation luminescence)>1000cd·m ^-2 ) The wavelength is 550nm, the external quantum efficiency reaches 1.0 percent, and the method has great practical significance. In 1994, kido et al in Japan produced for the first time a white light-emitting organic electroluminescent device. The fluorescent dyes with 3 colors of blue, green and orange are doped in a poly (N-vinyl carbazole) (PVK) film to be used as a hole transport layer and an emission layer, 1,2,4-triazole derivative (TAZ) is used as a hole blocking layer, 8-hydroxyquinoline aluminum (Alq 3) is used as an electron transport layer, and the device is composed of a glass substrate/ITO/PVK/TAZ/Alq 3/Mg: ag multilayer structure, and under the drive voltage of 14V, the wide visible light coverage range and the high brightness of 3400 cd.m can be obtained ^-2 The high brightness white emission is formed by doping fluorescent compounds of multiple colors into a polymer film to form a single light emitting layerTo achieve the purpose. The discovery of Kido et al adds a strong color of thick ink to the application of organic electroluminescence, opens the door of the organic light-emitting device in the field of illumination, and promotes the further development of the organic light-emitting device.

Light emitted from the organic electroluminescent device is also classified into fluorescence and phosphorescence, and light emitted by energy of singlet excitons is fluorescence, while light emitted by energy of singlet and triplet excitons is phosphorescence. Since the number of singlet and triplet states formed by excitons has a fixed value of 1:3, the internal quantum efficiency of a fluorescent device using only singlet excitons is theoretically only 25% at the highest, whereas the internal quantum efficiency when phosphorescence is emitted can reach 100%.

At present, both an organometallic complex having phosphorescent emission and an organic electroluminescent device are reported, but in many applications such as TV and lighting, the OLED lifetime is insufficient and there is still a need for higher efficiency OLEDs. Typically, the higher the luminance of an OLED, the shorter the lifetime of the OLED. Therefore, for a display that is used for a long time and has high resolution, an OLED having high luminous efficiency and a long lifetime is required.

In the prior art, a large number of phosphorescent materials are disclosed, and when the materials are applied to an organic electroluminescent device, some materials have longer service life and some materials have higher external quantum efficiency, but the materials often cannot have both the service life and the efficiency, and in practical application, the materials need to be selected according to requirements.

In view of the above problems, the present invention seeks to provide an organic electroluminescent device with improved overall performance.

Disclosure of Invention

The invention aims to develop a novel organic electroluminescent material, and a luminescent layer doped with a plurality of guest luminescent materials is obtained by combining two different metal complexes of a first compound and a second compound, so that the prepared organic electroluminescent device can obtain lower voltage, higher luminescent efficiency and longer service life, and the performance of the device can be obviously improved.

Specifically, in a first aspect, the invention provides an organic electroluminescent material, which comprises a first compound and a second compound, wherein the first compound and the second compound are respectively and independently selected from structures shown in a general formula (I), and the first compound and the second compound are different;

wherein:

R ¹ ～R ¹¹ independently selected from hydrogen atom, deuterium atom, alkyl group, deuterated alkyl group, cyano group, alkoxy group, alkylamino group, alkylthio group, fluorine atom, trifluoromethyl group, aryl group and heterocyclic aryl group, and/or R ¹ ～R ¹¹ Wherein adjacent substituents form a fused ring structure by bridging;

l is a monovalent bidentate anion, wherein the bonding atoms X, Y are each independently selected from the group consisting of oxygen atoms, nitrogen atoms, carbon atoms;

n is 1,2 or 3.

As an embodiment of the present invention, L is phenylpyridyl, substituted phenylpyridyl, acetylacetonate or substituted acetylacetonate;

preferably, L is a group of formula L1 or formula L2:

wherein:

in the formula L1, R ¹² ～R ¹⁹ Independently selected from hydrogen atom, deuterium atom, alkyl group, deuterated alkyl group, alkoxy group, alkylamino group, alkylthio group, fluorine atom, trifluoromethyl group, aryl group and heterocyclic aryl group, and/or R ¹² ～R ¹⁹ Wherein adjacent substituents form a fused ring structure by bridging;

in the formula L2, R ²⁰ ～R ²⁶ Independently selected from hydrogen atom, deuterium atom, alkyl, deuterated alkyl, alkoxy and alkylAmino group, alkylthio group, fluorine atom, trifluoromethyl group, aryl group and heterocyclic aryl group, and/or, R ²⁰ ～R ²⁶ Wherein adjacent substituents form a fused ring structure by bridging.

Further preferably, said L is selected from the following group:

as a preferred embodiment of the present invention, the first compound and the second compound are each independently selected from compounds represented by formula I or formula II or formula III;

preferably, the first compound and the second compound are both selected from compounds shown in a general formula I, or both selected from compounds shown in a general formula II, or both selected from compounds shown in a general formula III, and the first compound and the second compound are not the same;

wherein m is 1 or 2.

R in the general formula I ¹ ～R ¹¹ As previously defined.

R in formula II or formula III ¹ ～R ²⁶ As previously defined.

As a preferred embodiment of the present invention, in the above general formula (I) or general formula I or general formula II or general formula III, R is ¹ ～R ¹¹ Each independently selected from hydrogen atom, deuterium atom, C ₁ ～C ₅ Alkyl of (C) ₁ ～C ₅ Deuterated alkyl, cyano, alkoxy containing 1-5C atoms, alkylamino containing 1-5C atoms, alkylthio containing 1-5C atoms, fluorine atom, trifluoromethyl, phenyl, substituted phenyl, and heterocyclic aromatic group; and/or, R ¹ ～R ¹¹ Wherein adjacent substituents form a fused ring structure by bridging, the fused ring structure being a substituted or unsubstituted five-membered ring, a substituted or unsubstituted six-membered ring, a substituted or unsubstitutedAny one of a substituted five-membered heterocyclic ring and a substituted or unsubstituted six-membered heterocyclic ring, and the substituent adopted for the substitution is C ₁ ～C ₅ The number of the hetero atoms contained in the five-membered heterocyclic ring or the six-membered heterocyclic ring is at least one, and the hetero atoms are selected from oxygen atoms, sulfur atoms and nitrogen atoms.

In this application, C ₁ ～C ₅ The alkyl group of (b) may be a straight-chain alkyl group or a branched-chain alkyl group such as methyl, ethyl, n-propane, isopropyl, sec-butyl, n-butyl, isobutyl, tert-butyl, pentyl, neopentyl and the like.

C ₁ ～C ₅ Is C with part of the hydrogen atoms being replaced by deuterium ₁ ～C ₅ Alkyl of (2), likewise C ₁ ～C ₅ The alkyl group of (a) may be a straight-chain alkyl group or an alkyl group having a branched chain. C ₁ ～C ₅ The deuterated alkyl group of (a) may be, for example, deuterated methyl, deuterated isopropyl, deuterated pentyl, deuterated neopentyl, etc.

Alkoxy containing 1 to 5C atoms is C _n H _2n+1 O-, wherein n is 1 to 5. The alkoxy group having 1 to 5 carbon atoms may be a methoxy group, an ethoxy group or the like.

R ¹ ～R ¹¹ The adjacent substituents in (b) may also form a fused-ring structure by bridging, and when the fused-ring structure is formed, the fused-ring structure may be any one of a substituted or unsubstituted five-membered ring, a substituted or unsubstituted six-membered ring, a substituted or unsubstituted five-membered heterocyclic ring, and a substituted or unsubstituted six-membered heterocyclic ring. At least one heteroatom is contained in the five-membered heterocyclic ring or the six-membered heterocyclic ring, and the heteroatom is selected from oxygen atom, sulfur atom and nitrogen atom. For example, the fused ring structure may be a benzo ring, a furo ring, a thieno ring, a cyclopenteno ring, or the like. The fused ring structure may be further substituted with a substituent, for example, with a benzo group, with an alkyl group, or the like.

As a preferred embodiment of the present invention, in the general formula II, R is as described above ¹² ～R ¹⁹ Each independently selected from hydrogen atom, deuterium atom, and C ₁ ～C ₅ Alkyl group, fluorine atom, phenyl group, substituted phenyl group, C ₁ ～C ₅ Deuterated alkyl, cyano, alkoxy containing 1-5C atoms, alkylamino containing 1-5C atoms, alkylthio containing 1-5C atoms, trifluoromethyl and heterocyclic aromatic group; or, R ¹² ～R ¹⁹ Wherein adjacent substituents form a fused ring structure through bridging, 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 heterocyclic ring and a substituted or unsubstituted six-membered heterocyclic ring, and the substituent adopted for substitution is C ₁ ～C ₅ The alkyl, phenyl, benzo, pyrido, alkyl-substituted pyrido, deuterated alkyl-substituted pyrido, the five-membered heterocycle or six-membered heterocycle contains at least one heteroatom, and the heteroatom is selected from oxygen atom, sulfur atom, and nitrogen atom.

As a preferred embodiment of the present invention, in the formula III, R is as defined above ²⁰ ～R ²⁶ Each independently selected from hydrogen atom, deuterium atom, and C ₁ ～C ₅ Alkyl group of (2), fluorine atom, C ₁ ～C ₅ Deuterated alkyl, alkoxy containing 1-5C atoms, alkylamino containing 1-5C atoms, alkylthio containing 1-5C atoms and trifluoromethyl.

As a further preferred embodiment of the present invention, in the above general formula (I) or general formula I or general formula II or general formula III, wherein R is ¹ ～R ¹¹ Each independently selected from hydrogen atom and C ₁ ～C ₅ Alkyl of (C) ₁ ～C ₅ Deuterated alkyl, phenyl, fluorine atom, alkoxy containing 1 to 5C atoms, trifluoromethyl; or, R ¹ ～R ¹¹ Wherein adjacent substituents form a fused ring structure through bridging, the fused ring structure is any one of a substituted or unsubstituted five-membered ring, a substituted or unsubstituted benzene ring and a substituted or unsubstituted five-membered heterocycle, and the substituent adopted for substitution is C ₁ ～C ₅ At least one heteroatom of the five-membered heterocyclic ring is selected from oxygen atom and sulfur atom.

More preferably, wherein R ¹ ～R ¹¹ Are independently controlledIs selected from hydrogen atom, methyl, deuterated methyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, deuterated isopropyl, phenyl, pentyl, deuterated pentyl, fluorine atom, methoxy group; or, R ¹ ～R ¹¹ Wherein adjacent substituents form a fused ring structure through bridging, the fused ring structure is any one of a substituted or unsubstituted benzene ring, a substituted or unsubstituted furan ring, a substituted or unsubstituted thiophene ring and a substituted or unsubstituted cyclopentene ring, and substituents used for substitution are a benzo group and a methyl group.

As a further preferred embodiment of the present invention, in formula II, said R is ¹² ～R ¹⁹ Each independently selected from hydrogen atom, C ₁ ～C ₅ Alkyl group, fluorine atom, phenyl group, C ₁ ～C ₅ Deuterated alkyl of (a); or, R ¹² ～R ¹⁹ Wherein adjacent substituent groups form a fused ring structure through bridging, the fused ring structure is any one of a substituted or unsubstituted benzene ring and a substituted or unsubstituted five-membered heterocycle, and the substituent group adopted by the substitution is C ₁ ～C ₅ The heterocyclic ring is an alkyl group, a phenyl group, a benzo group, a pyrido group, an alkyl group substituted pyrido group containing 1 to 5C atoms, or a deuterated alkyl group substituted pyrido group containing 1 to 5C atoms, the five-membered heterocyclic ring contains at least one heteroatom, and the heteroatom is optionally selected from an oxygen atom and a sulfur atom.

More preferably, wherein R ¹² ～R ¹⁹ Independently and optionally selected from hydrogen atom, methyl, fluorine atom, phenyl, deuterated methyl, isopropyl and deuterated isopropyl; or, R ¹² ～R ¹⁹ Wherein adjacent substituents form a fused ring structure through bridging, the fused ring structure is any one of a substituted or unsubstituted benzene ring, a substituted or unsubstituted furan ring and a substituted or unsubstituted six-membered ring, and the substituent adopted for substitution is a deuterated methyl-substituted pyrido group, a methyl-substituted pyrido group or a benzo group.

As a further preferred embodiment of the present invention, in the above general formula III, R is ²⁰ ～R ²⁶ Each independently selected from hydrogen atom, deuterium atom, C ₁ ～C ₅ Alkyl group of (1).

More preferably, wherein R ²⁰ ～R ²⁶ Each independently selected from hydrogen atom, methyl group and ethyl group.

As a preferred embodiment of the present invention, the organic electroluminescent material, wherein the first compound and the second compound are each independently selected from compounds represented by the following structural formulae, and the first compound and the second compound are not the same;

/>

/>

/>

/>

preferably, the first compound and the second compound are respectively and independently selected from compounds shown in I-1-I-30, and the first compound and the second compound are not the same;

or the first compound and the second compound are respectively and independently selected from compounds shown in II-1-II-44, and the first compound and the second compound are different;

or the first compound and the second compound are respectively and independently selected from compounds shown in III-1 to III-20, and the first compound and the second compound are different.

As a preferred embodiment of the present invention, in the organic electroluminescent material, the mixing mass ratio of the first compound and the second compound is between 1.

Preferably, the mixed mass ratio of the first compound and the second compound is between 1:4 and 5:1, and further preferably, the mixed mass ratio of the first compound and the second compound is between 1:4 and 4:1.

In a second aspect, the invention provides the use of the organic electroluminescent material in the preparation of an organic electroluminescent device.

Preferably, the organic electroluminescent material is used as a doping material of a light emitting layer in an organic electroluminescent device.

Further preferably, in the light-emitting layer, the organic electroluminescent material accounts for 4% to 20% of the total mass of the light-emitting layer, and more preferably 4% to 10%.

In a third aspect, the present invention provides an organic electroluminescent device made of the organic electroluminescent material, including:

an anode, a cathode, a anode and a cathode,

a cathode electrode, which is provided with a cathode,

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

Preferably, the light-emitting layer includes a host material and a dye material, and the dye material includes the organic electroluminescent material of the present invention.

Further preferably, the doping concentration of the organic electroluminescent material of the present invention in the light-emitting layer is 4 to 20%, preferably 4 to 10%, and more preferably 5 to 9%.

As a preferred embodiment of the present invention, the host material of the organic electroluminescent device comprises at least one chemical group selected from the group consisting of: benzene, pyridine, pyrimidine, triazine, carbazole, azacarbazole, indolocarbazole, dibenzothiophene, azadibenzothiophene, dibenzofuran, azadibenzofuran, dibenzoselenophene, triphenylene, azatriphenylene, fluorene, silafluorene, naphthalene, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene, azaphenanthrene, and combinations thereof.

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

In a fourth aspect, the present invention provides a display assembly comprising an organic electroluminescent device according to the present invention.

The invention provides a novel organic electroluminescent device, wherein a light-emitting layer is doped with a plurality of guest light-emitting materials together, and the prepared organic electroluminescent device can obtain lower voltage, higher luminous efficiency and longer service life and can obviously improve the performance of the device by using the combination of two different metal complexes of a first compound and a second compound.

Drawings

FIG. 1 is a nuclear magnetic hydrogen spectrum of compound III-1;

FIG. 2 is a nuclear magnetic hydrogen spectrum of compound III-2;

FIG. 3 is a nuclear magnetic hydrogen spectrum of compound III-3;

FIG. 4 is a nuclear magnetic hydrogen spectrum of Compound II-2.

Detailed Description

The technical solution of the present invention will be explained in detail below.

OLEDs can be fabricated on a variety of substrates, such as glass, plastic, and metal. The 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. Can be fabricated by depositing the described layers sequentially. The properties and functions of the various layers, as well as exemplary materials, are described in more detail in U.S. patent US7,279,704B2, columns 6-10, which is incorporated herein by reference in its entirety.

There are more instances of each of these layers. For example, a flexible and transparent substrate-anode combination is disclosed in U.S. Pat. No. 5,844,363, which is incorporated by reference in its entirety. An example of a p-doped hole transport layer is doped with F at a molar ratio of 50 ₄ m-MTDATA of TCNQ, as disclosed in U.S. patent application publication No. 2003/0230980, which is incorporated by reference in its entirety. The full disclosure of which is incorporated by referenceExamples of host materials are disclosed in U.S. Pat. No. 6,303,238 to Thompson et al. 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 by reference in its entirety. U.S. Pat. Nos. 5,703,436 and 5,707,745, which are incorporated by reference in their entirety, disclose examples of cathodes including composite cathodes having a thin layer of a metal such as Mg: ag and an overlying layer of transparent, conductive, sputter-deposited ITO. 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 incorporated by reference in their entirety. Examples of implant layers are provided in U.S. patent application publication No. 2004/0174H6, which is incorporated by reference in its entirety. A description of a protective layer can be found in U.S. patent application publication No. 2004/0174H6, which is incorporated by reference in its entirety.

The above-described layered structure is provided by way of non-limiting example. The function of the OLED may be achieved by combining the various layers described above, or some layers may be omitted entirely. It may also include other layers not explicitly described.

Devices manufactured according to embodiments of the present invention may be incorporated into various consumer products having one or more electronic component modules (or units) of the device. 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, smart phones, tablet computers, tablet handsets, wearable devices, smart watches, laptop computers, digital cameras, camcorders, viewfinders, micro-displays, 3-D displays, vehicle displays, and tail lights.

The materials and structures described herein may also be used in other organic electronic devices as previously listed.

The particular materials described herein for use in organic light emitting devices may be used in combination with various other materials present in the device. Combinations of these materials are described in detail in U.S. patent application Ser. No. 0132-0161, paragraphs 2016/0359122A1, which is hereby incorporated by reference in its entirety. The materials described or mentioned therein are non-limiting examples of materials that can be used in combination with the compounds disclosed herein, and one skilled in the art can readily review the literature to identify other materials that can be used in combination.

Materials described herein as being useful for particular layers in an organic light emitting device can be used in combination with a variety of other materials present in the device. For example, the compounds disclosed herein may be used in conjunction with a variety of hosts, transport layers, barrier layers, injection layers, electrodes, and other layers that may be present. Combinations of these materials are described in detail in U.S. patent application US2015/0349273A1, paragraphs 0080-0101, which is incorporated herein by reference in its entirety. The materials described or referenced therein are non-limiting examples of materials that may be used in combination with the compounds disclosed herein, and one skilled in the art can readily review the literature to identify other materials that may be used in combination.

In the examples of material synthesis, all reactions were carried out under nitrogen unless otherwise stated. All reaction solvents were anhydrous and used as received from commercial sources. The resultant product is subjected to structural validation and characterization using one or more equipment conventional in the art (including, but not limited to, agilent's liquid chromatograph, liquid chromatograph-mass spectrometer, gas chromatograph-mass spectrometer, differential scanning calorimeter, fluorescence spectrophotometer, electrochemical workstation, sublimator, etc.) in a manner well known to those skilled in the art. In an embodiment of the device, the device is prepared and tested using equipment conventional in the art (including, but not limited to, an evaporator manufactured by Nanjing Mike, optical testing systems manufactured by Fushida, suzhou, an optical testing system, a life testing system, an ellipsometer manufactured by Yinggan technology, etc.) in a manner well known to those skilled in the art. Since the person skilled in the art knows the relevant contents of the above-mentioned device usage, testing method, etc., and can obtain the intrinsic data of the sample with certainty and without influence, the above-mentioned relevant contents are not repeated in this patent.

The technical solution of the present invention will be further described below by way of specific examples. The following examples are given solely for the purpose of illustration and are not intended to limit the scope of the invention, which is intended to include within the scope of the appended claims all such equivalent changes and modifications as may be made without departing from the spirit and scope of the invention as disclosed.

The preparation methods of the first compound and the second compound selected by the invention are not limited, and the following compounds are typically but not limited to, and the synthetic routes and the preparation methods thereof are as follows.

EXAMPLE 1 Synthesis of ligand P1

The synthetic route is as follows:

the specific experimental steps are as follows:

(1) 2-fluoronitrobenzene (14.1g, 0.1mol) and 2-bromoaniline (25.7g, 0.15mol) are added into a 2L three-neck flask with mechanical stirring, stirred and heated to 180 ℃ under the protection of argon, the temperature is kept for reaction for more than 30 hours, and the color gradually turns into red in the reaction process and finally turns into deep red gradually. After the reaction was completed, the organic phase was separated, extracted, dried, column chromatographed, and the solvent was spin-dried to obtain 24.8g of an orange-red solid M1 with a yield of 85%.

(2) To a 1L three-necked flask equipped with a mechanical stirrer, M1 (29.2g, 0.1 mol), sodium sulfide nonahydrate (96g, 0.4 mol), ethanol (200 mL), water (100 mL) and nitrogen were added, and the mixture was heated to reflux and refluxed for 3 hours to complete the reaction. The organic phase was separated, extracted, dried, column chromatographed, and the solvent was spin-dried to give 22.8g of white solid M2 with a yield of 87%.

(3) In a 1L three-necked flask equipped with a mechanical stirrer, M2 (26.2 g,0.1 mol) and 300mL of acetone were added to be completely dissolved, a solution of KOH (11.2 g,0.2 mol) dissolved in water (50 mL) was added, o-bromobenzoyl chloride (22g, 0.1 mol) was slowly added dropwise to the flask, a solid was gradually precipitated from the flask, and after completion of the addition, the reaction was carried out at room temperature for 2 hours, and the reaction was terminated. Adjusting to neutrality, separating an organic phase, extracting, drying, performing column chromatography, and spin-drying the solvent to obtain 33.9g of white solid M3 with the yield of 76%.

(4) Adding M3 (44.6 g,0.1 mol) into a 1L three-necked flask, adding 200mL of glycol ether (DEG), protecting with nitrogen, gradually heating to reflux, gradually dissolving the solid, magnetically stirring, keeping the temperature for reaction for 3 hours, and finishing the reaction. The organic phase was separated, extracted, dried, column chromatographed and the solvent dried to give 34.7g of a pale pink solid M4 in 81% yield.

(5) Under the protection of nitrogen, 800mL of M4 (42.8g, 0.1mol) and 800mL of anhydrous THF were added to a 2L three-necked flask, the flask was cooled to-78 ℃, a 2.5M n-hexane solution of n-butyllithium (100mL, 0.25mol) was slowly added dropwise with stirring for about 30mins, the dropping funnel was flushed with 50mL of anhydrous THF, and the temperature was maintained for 1.5 hours to obtain a reaction solution of M5. In a low-temperature system at-78 ℃, sulfur dichloride (1695 ml, 0.25mol) is slowly dripped, then a small amount of anhydrous THF is used for flushing a dropping funnel, the temperature is kept for 1 hour after the addition, then the temperature is slowly raised to room temperature, the reaction is stirred for 4 hours at room temperature, and the reaction is finished. Adjusting to neutrality, separating an organic phase, extracting, drying, performing column chromatography, and spin-drying the solvent to obtain 26.6g of white solid P1 with the yield of 58%.

Product MS (m/e): 300.07; elemental analysis (C) ₁₉ H ₁₂ N ₂ S): theoretical value C:75.97%, H:4.03%, N:9.33 percent; found value C:76.08%, H:4.11%, N:9.16 percent.

¹ HNMR(500MHz,CDCl ₃ )δ:8.16(dd,J＝7.4,1.2Hz,1H),7.73(dd,J＝6.4,1.6Hz,1H),7.75(dd,J＝7.1,1.6Hz,1H),7.63–7.54(m,2H),7.47-7.25(m,7H)。

EXAMPLE 2 Synthesis of Compound III-1

The reaction formula is as follows:

the specific experimental steps are as follows:

(1) In a 500mL three-neck flask equipped with a mechanical stirring device, a reflux condensing device and a nitrogen protection device, sequentially adding: ligand P1 (25mmmol, 7.5 g), iridium trichloride hydrate (10mmol, 3.35g), 90mL of ethylene glycol monoethyl ether and 30mL of distilled water. Vacuumizing and filling N ₂ Repeating the steps for 5 times to remove oxygen in the system. Heated to 110 ℃ under reflux for 24 hours. After natural cooling, 10mL of distilled water is added, and the mixture is shaken, filtered, washed with water and washed with ethanol. Vacuum drying gave 5.9g of crude M6, a yellow solid, as the dichloro-bridged intermediate.

(2) To a 250mL three-necked flask equipped with a magnetic stirring and reflux condenser, the above intermediate M6 (5 mmol,8.3 g), acetylacetone (25mmol, 2.5 g, 2.6 mL), and anhydrous Na were added in this order ₂ CO ₃ (22mmol, 2.35 g) and 100mL of ethylene glycol monoethyl ether. Vacuumizing and filling N ₂ Repeating the steps for 5 times to remove oxygen in the system. N is a radical of ₂ Heated to reflux for 24 hours in an oil bath at 120 ℃ under protection. Naturally cooling to room temperature, filtering, washing with water, n-hexane and diethyl ether in sequence, and drying to obtain a yellow crude product. By CH ₂ Cl ₂ Column separation after dissolution, eluent CH ₂ Cl ₂ The solvent was then drained to give 7.4 g of a yellow powder.

Product MS (m/e): 890; elemental analysis (C) ₄₃ H ₂₉ IrN ₄ O ₂ S ₂ ): theoretical value C:58.03%, H:3.28%, N:6.29 percent; found value C:58.01%, H:3.32%, N:6.40 percent. The nuclear magnetic hydrogen spectrum of the product compound III-1 is shown in FIG. 1.

EXAMPLE 3 Synthesis of Compound III-2

Compound III-2 was synthesized by using 3,7-diethylnonane-4,6-dione in place of acetylacetone, and the other starting materials and procedures were the same as in example 1.

Product MS (m/e): 1002.55; elemental analysis (C) ₅₁ H ₄₅ IrN ₄ O ₂ S ₂ ): theoretical value C:61.12%, H:4.53%, N:5.59 percent; found value C:61.22%, H:4.48%, N:5.63 percent. The nuclear magnetic hydrogen spectrum of the product compound III-2 is shown in FIG. 2.

EXAMPLE 4 Synthesis of Compound III-3

The compound III-3 was synthesized by using 2,2,6,6-tetramethylheptane-3,5-dione instead of acetylacetone and the other raw materials and procedures were the same as in example 1.

Product MS (m/e): 974.62; elemental analysis (C) ₄₉ H ₄₁ IrN ₄ O ₂ S ₂ ): theoretical value C:60.41%, H:4.24%, N:5.75 percent; found value C:60.52%, H:4.16%, N:5.69 percent. The nuclear magnetic hydrogen spectrum of the product compound III-3 is shown in FIG. 3.

EXAMPLE 5 Synthesis of Compound II-2

The reaction formula is as follows:

the specific experimental steps are as follows:

(1) In a 100mL three-necked flask equipped with a mechanical stirring device, a reflux condenser and a nitrogen gas protector, phenylpyridine (15mmol, 2.5mL), iridium trichloride hydrate (6mmol, 2.01g), 45mL of ethylene glycol monoethyl ether and 15mL of distilled water were sequentially added. Vacuumizing and filling N ₂ Repeating the steps for five times to remove oxygen in the system. Heated to 110 ℃ under reflux for 24 hours. After natural cooling, 10mL of distilled water is added, and the mixture is shaken, filtered, washed with water and washed with ethanol. Vacuum drying to obtain 26g of crude M7, a yellow solid, dichloro bridged intermediate.

(2) In a 500mL three-necked flask equipped with a nitrogen blanket, dichloro-bridged intermediate M7 (10.7g, 10mmol) was sequentially added, 150mL of dichloromethane was added, and the mixture was sufficiently stirred, then 200mL of a methanol solution of silver trifluoromethanesulfonate (6.4g, 25mmol) was added, and the mixture was stirred for 24 hours in the dark, cooled to room temperature, the formed AgCl was filtered off with celite, and the filtrate was spin-dried to obtain a yellowish solid powder. The solid was used in the next reaction without further treatment.

(3) In a 250ml three-necked flask, the yellowish solid (5.1g, 6.9 mmol) obtained in the above step (2) and the ligand P1 (6 g, 21mmol) were charged, then 100ml of ethanol was added, the mixture was heated under reflux for 36 hours, the reaction was cooled to room temperature, the resultant yellow solid was filtered, and this solid was dissolved in methylene chloride and subjected to column chromatography to obtain 10.2 g of a bright yellow solid.

Product MS (m/e): 800; elemental analysis (C) ₄₁ H ₂₇ IrN ₄ S): theoretical value C:61.56%, H:3.40%, N:7.00 percent; found value C:61.61%, H:3.46%, N:7.05 percent. The nuclear magnetic hydrogen spectrum of the product compound II-2 is shown in FIG. 4.

EXAMPLE 6 Synthesis of Compound I-1

The reaction formula is as follows:

the specific experimental steps are as follows: ir (acac) was added sequentially to a 250ml three-necked flask equipped with a magnetic stirring and reflux condenser ₃ (10mmol, 4.9 g), ligand P1 (40mmol, 12 g), and glycerol 150mL. Vacuumizing, filling N ₂ Repeating the above steps for 5 times to remove oxygen in the system. N is a radical of hydrogen ₂ Heated to reflux in an oil bath at 190 ℃ for 24 hours with protection. Naturally cooling to room temperature, filtering, washing with water, n-hexane, and diethyl ether, and drying to obtain yellowAnd (4) coloring a crude product. By CH ₂ Cl ₂ Column separation after dissolution, eluent CH ₂ Cl ₂ The solvent was drained to give 4.5 g of a yellow powder with a yield of 41%.

Product MS (m/e): 1090; elemental analysis (C) ₅₇ H ₃₃ IrN ₆ S ₃ ): theoretical value C:62.79%, H:3.05%, N:7.71 percent; measured value C:62.85%, H:3.11%, N:7.64 percent.

Compounds II-18, II-20 and I-6 were synthesized with reference to the above synthesis methods.

Other specific compounds in the invention can be synthesized by referring to the preparation method disclosed in the patent application with the publication number of CN 112175016A.

It will be appreciated by those skilled in the art that the above preparation method is only an illustrative example, and that those skilled in the art will be able to modify it to obtain other compound structures of the present invention.

Device examples 1 to 10

Several specific embodiments of devices are provided below. The method of fabricating the organic electroluminescent device according to the present invention is not particularly limited, and the method of fabricating the following embodiment is only an example and should not be construed as limiting. The preparation of the following examples can be reasonably modified by one skilled in the art based on the prior art.

Device example 1

The embodiment provides an organic electroluminescent device, which is prepared by the following steps:

first, a glass substrate having an Indium Tin Oxide (ITO) anode 120nm thick was cleaned and treated with UV ozone and oxygen plasma; after the treatment, the substrate was dried in a glove box filled with nitrogen gas to remove moisture, and then the substrate was mounted on a substrate holder and loaded into a vacuum chamber;

the organic layer was then deposited, the organic layer specified below, in a vacuum of about 10 ^-8 In the case of Torr

On an ITO anode in turn by thermal vacuumCarrying out evaporation;

the compound HT and NDP-9 are sequentially and simultaneously evaporated to form a Hole Injection Layer (HIL) with a thickness of

The compound HT is used as Hole Transport Layer (HTL) with a thickness of

The compound TAPC is used as an Electron Blocking Layer (EBL) with a thickness of

DIC-TRZ as a host compound, a compound III-1 as a first dopant and a compound III-2 as a second dopant were co-evaporated to form a light-emitting layer (EML) having a thickness of

Wherein the host compound DIC-TRZ accounts for 94% of the total weight of the light-emitting layer, the compound III-1 accounts for 3% of the total weight of the light-emitting layer, and the compound III-2 accounts for 3% of the total weight of the light-emitting layer; the difference of the evaporation temperature of the compound III-1 and the compound III-2 in the device preparation process is less than 15 ℃, and preferably, the difference of the evaporation temperature is less than 5 ℃;

the compound TPBI is used as a Hole Blocking Layer (HBL) with a thickness of

On the hole-blocking layer, the compound ET01 and 8-hydroxyquinoline-lithium (Liq) were co-evaporated as an electron-transporting layer (ETL) with a thickness of

Wherein compounds ET01 and Liq each comprise 50% of the total weight of the electron transport layer;

finally, evaporation

LiF having a thickness as an Electron Injection Layer (EIL) and evaporated onto a substrate>

As a cathode.

The device was then transferred back to the glove box and encapsulated with a glass lid to complete the device.

Device example 2

Device example 2 was prepared with reference to device example 1, except that in the light emitting layer (EML), the compound III-2 was changed from 3% to 6% of the total weight of the light emitting layer, and the host compound DIC-TRZ was changed from 94% to 91% of the total weight of the light emitting layer.

Device example 3

Device example 3 was prepared with reference to device example 1, except that in the light emitting layer (EML), the compound III-1 was changed from 3% to 1% by weight, the compound III-2 was changed from 3% to 4% by weight, and the host compound DIC-TRZ was changed from 94% to 95% by weight, based on the total weight of the light emitting layer.

Device example 4

Device example 4 was prepared with reference to device example 1, except that in the light emitting layer (EML), compound III-2 was replaced with compound III-3.

Device example 5

Device example 5 preparation was carried out with reference to device example 1, except that in the light-emitting layer (EML), compound III-1 was replaced by compound III-3.

Device example 6

Device example 6 was prepared with reference to device example 1, except that in the light emitting layer (EML), compound III-2 was replaced with compound II-2.

Device example 7

Device example 7 was prepared with reference to device example 1, except that in the light emitting layer (EML), compound III-2 was replaced with compound I-1.

Device example 8

Device example 8 was prepared with reference to device example 1, except that in the light emitting layer (EML), compound III-1 was replaced with II-2 and compound III-2 was replaced with II-18.

Device example 9

Device example 9 fabrication was performed with reference to device example 1, except that in the light emitting layer (EML), compound III-1 was replaced with II-2 and compound III-2 was replaced with II-20.

Device example 10

Device example 10 was prepared with reference to device example 1, except that in the light emitting layer (EML), compound III-1 was replaced with I-1 and compound III-2 was replaced with I-6.

Device comparative example 1

Device comparative example 1 was prepared with reference to device example 1, except that in the light emitting layer (EML), the second dopant compound III-2 was replaced with III-1.

Device comparative example 2

Device comparative example 2 was prepared with reference to device example 1, except that in the light emitting layer (EML), both the first dopant compound III-1 and the second dopant compound III-2 were replaced with II-2.

Device comparative example 3

Device comparative example 3 was prepared with reference to device example 1, except that in the light emitting layer (EML), both the first dopant compound III-1 and the second dopant compound III-2 were replaced with I-1.

The detailed device layer structures and thicknesses of the above device examples and comparative examples are shown in table 1 below. Wherein more than one of the materials used was obtained by doping different compounds in the weight ratios described in Table 1.

TABLE 1 device structures of device examples and comparative examples

/>

The material structures used in the above devices are as follows:

performance tests were conducted on the device examples and comparative examples prepared above and are listed in Table 2 at 20mA/cm ² Under the conditions, the Voltage (Voltage, V), current Efficiency (CE) and device Lifetime (LT) of device examples 1 to 9 and device comparative examples 1 to 3 were measured ₉₇ ) And (6) detecting the result.

TABLE 2 device Performance test data

/>

Through the detection data of the above devices, we can find that: device examples 1 to 10 compared with device comparative examples 1 to 3, that is, the light emitting layer is doped with a plurality of guest light emitting materials together, compared with the case of doping with a single light emitting material, the use of two metal complexes as dopants is significantly improved in comparison with the use of a single metal complex as a dopant regardless of voltage, current efficiency or lifetime, and the organic electroluminescent device obtained can obtain a lower voltage, a higher light emitting efficiency and a longer lifetime, can significantly improve the device performance, and brings an unpredictable effect to the device performance.

It can be seen from the device data of examples 1 to 3 that the device performance obtained by changing the ratio of the two metal complex dopants in the light-emitting layer to the total weight of the light-emitting layer and the mass ratio of the two metal complex dopants also significantly changes. 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 voltage is the smallest, the current efficiency is the largest, and the lifetime is the longest.

Comparing the device detection data of examples 1, 4 to 5,8 to 10 and examples 6 to 7, it can be seen that the more similar the compound structures of the two metal complex dopants are, the better the device performance prepared by using the metal complex dopants as the luminescent layer doping material is, especially in examples 8 and 9, the current efficiency is obviously improved, and the lifetime is unexpectedly improved.

In summary, the combination of the first metal complex and the second metal complex of the present invention shows excellent overall device performance in the device, lower driving voltage, higher efficiency and ultra-long device lifetime, because the two compounds can be well matched with each other in terms of energy.

Although the invention has been described in detail hereinabove by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that modifications and improvements can be made thereto without departing from the scope of the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. An organic electroluminescent material is characterized by comprising a first compound and a second compound, wherein the first compound and the second compound are respectively and independently selected from structures shown in a general formula (I), and the first compound and the second compound are different;

wherein:

n is 1,2 or 3.

2. The light-emitting material according to claim 1, wherein L is a phenylpyridyl group, a substituted phenylpyridyl group, an acetylacetonate group, or a substituted acetylacetonate group;

preferably, L is a group of formula L1 or formula L2:

wherein:

in the formula L2, R ²⁰ ～R ²⁶ Independently of one another, are selected from the group consisting of hydrogen, deuterium, alkyl, deuterated alkyl, alkoxy, alkylamino, alkylthio, fluorine, trifluoromethyl, aryl and heteroaryl, and/or R ²⁰ ～R ²⁶ Wherein adjacent substituents form a fused ring structure by bridging.

3. The luminescent material according to claim 2, wherein the first compound and the second compound are each independently selected from compounds represented by general formula I, general formula II, or general formula III;

wherein m is 1 or 2.

4. The phosphorescent light-emitting material according to claim 2 or 3, wherein R is ¹ ～R ¹¹ Each independently selected from hydrogen atom, deuterium atom, C ₁ ～C ₅ Alkyl of (C) ₁ ～C ₅ Deuterated alkyl, cyano, alkoxy containing 1-5C atoms, alkylamino containing 1-5C atoms, alkylthio containing 1-5C atoms, fluorine atom, trifluoromethyl, phenyl, substituted phenyl, and heterocyclic aromatic group; and/or, R ¹ ～R ¹¹ Wherein adjacent substituent groups form a fused ring structure through bridging, 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, and the substituent group adopted for substitution is C ₁ ～C ₅ The alkyl, the phenyl and the benzo group of (1), wherein the five-membered heterocyclic ring or the six-membered heterocyclic ring contains at least one heteroatom which is optionally selected from oxygen atom, sulfur atom and nitrogen atom; and/or the presence of a gas in the atmosphere,

the R is ¹² ～R ¹⁹ Each independently selected from hydrogen atom, deuterium atom, C ₁ ～C ₅ Alkyl group, fluorine atom, phenyl group, substituted phenyl group, C ₁ ～C ₅ Deuterated alkyl, cyano, alkoxy containing 1-5C atoms, alkylamino containing 1-5C atoms, alkylthio containing 1-5C atoms, trifluoromethyl and heterocyclic aromatic group; and/or, R ¹² ～R ¹⁹ Wherein adjacent substituent groups form a fused ring structure through bridging, 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, and the substituent group adopted for substitution is C ₁ ～C ₅ The alkyl, phenyl, benzo, pyrido, alkyl-substituted pyrido, deuterated alkyl-substituted pyrido, the five-membered heterocycle or six-membered heterocycle contains at least one heteroatom, and the heteroatom is selected from oxygen atom, sulfur atom, and nitrogen atom; and/or the presence of a gas in the gas,

the R is ²⁰ ～R ²⁶ Each independently selected from hydrogen atom, deuterium atom, C ₁ ～C ₅ Alkyl group, fluorine atom, C ₁ ～C ₅ Deuterated alkyl, alkoxy containing 1 to 5C atoms, alkylamino containing 1 to 5C atoms, alkylthio containing 1 to 5C atoms and trifluoromethyl;

preferably, said R is ¹ ～R ¹¹ Each independently selected from hydrogen atom and C ₁ ～C ₅ Alkyl of (C) ₁ ～C ₅ Deuterated alkyl, phenyl, fluorine atom, alkoxy containing 1 to 5C atoms, trifluoromethyl; and/or, R ¹ ～R ¹¹ Wherein adjacent substituent groups form a fused ring structure through bridging, the fused ring structure is any one of a substituted or unsubstituted five-membered ring, a substituted or unsubstituted benzene ring and a substituted or unsubstituted five-membered hetero ring, and the substituent group adopted for substitution is C ₁ ～C ₅ At least one heteroatom of the five-membered heterocyclic ring is selected from oxygen atom and sulfur atom; and/or the presence of a gas in the gas,

the R is ¹² ～R ¹⁹ Each independently selected from hydrogen atom and C ₁ ～C ₅ Alkyl group, fluorine atom, phenyl group, C ₁ ～C ₅ Deuterated alkyl of (a); and/or, R ¹² ～R ¹⁹ Wherein adjacent substituent groups form a fused ring structure through bridging, the fused ring structure is any one of a substituted or unsubstituted benzene ring and a substituted or unsubstituted five-membered heterocycle, and the substituent group adopted by the substitution is C ₁ ～C ₅ The alkyl, phenyl, benzo, pyrido, alkyl substituted pyrido containing 1 to 5C atoms, deuterated alkyl substituted pyrido containing 1 to 5C atoms, the five-membered heterocyclic ring contains at least one heteroatom, and the heteroatom is optionally selected from oxygen atom and sulfur atom; and/or the presence of a gas in the gas,

said R is ²⁰ ～R ²⁶ Each independently selected from hydrogen atom, deuterium atom, C ₁ ～C ₅ Alkyl group of (1).

5. The light-emitting material according to any one of claims 1 to 4, wherein the first compound and the second compound are each independently selected from compounds represented by the following structural formulae, and the first compound and the second compound are different;

/>

/>

/>

/>

preferably, the first compound and the second compound are respectively and independently selected from compounds shown in I-1 to I-30, and the first compound and the second compound are different;

6. The luminescent material according to any one of claims 1 to 5, wherein the mixed mass ratio of the first compound and the second compound is between 1.

7. Use of the luminescent material according to any one of claims 1 to 6 for the preparation of an organic electroluminescent device;

preferably, the light emitting material is used as a doping material of a light emitting layer in an organic electroluminescent device;

more preferably, the light-emitting material accounts for 4% to 20%, and even more preferably 4% to 10% of the total mass of the light-emitting layer.

8. An organic electroluminescent device comprising the light-emitting material according to any one of claims 1 to 6, comprising:

an anode, a cathode, an anode and a cathode,

a cathode electrode, which is provided with a cathode,

and an organic layer disposed between the anode and the cathode, wherein the organic layer includes a light-emitting layer including the light-emitting material according to any one of claims 1 to 6;

preferably, the light emitting layer includes a host material and a dye material, the dye material including the light emitting material according to any one of claims 1 to 6;

further preferably, the doping concentration of the light-emitting material according to any one of claims 1 to 6 in the light-emitting layer is 4 to 20%, preferably 4 to 10%, more preferably 5 to 9%.

9. The organic electroluminescent device of claim 8, wherein the host material comprises at least one chemical group selected from the group consisting of: benzene, pyridine, pyrimidine, triazine, carbazole, azacarbazole, indolocarbazole, dibenzothiophene, azadibenzothiophene, dibenzofuran, azadibenzofuran, dibenzoselenophene, triphenylene, azatriphenylene, fluorene, silafluorene, naphthalene, quinoline, isoquinoline, quinazoline, quinoxaline, phenanthrene, azaphenanthrene, and combinations thereof.

10. A display module comprising the organic electroluminescent device according to claim 8 or 9.