Organic electroluminescent complex, preparation method thereof, light-emitting layer material and organic electroluminescent device

Abstract

The present invention relates to the field of organic electroluminescence technology, and in particular to an organic electroluminescent complex and a preparation method thereof, a luminescent layer material, and an organic electroluminescent device. The organic electroluminescent complex is selected from the compounds represented by the following structural formula: M (L A )2(L B ), where M represents metal, L A and L B They are respectively groups represented by the following structural formulas:; The organic electroluminescent complex has high air stability, and the organic electroluminescent device formed therefrom has the advantages of long life, high efficiency and low driving voltage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic electroluminescence, in particular to an organic electroluminescence complex, a preparation method thereof, a light-emitting layer material and an organic electroluminescence device. BACKGROUND

[0002] Organic light-emitting diodes (OLEDs) have been widely commercialized, especially in the field of flat panel displays. Among them, the most core raw material in OLED technology is an organic electroluminescence material. Traditional light-emitting materials such as fluorescent materials have an exciton utilization efficiency (EUE) of only 25% due to the limitation of spin statistics. Phosphorescent materials based on noble metal complexes can also emit light through radiative transition of triplet excitons due to spin-orbit coupling (SOC) effect, and the EUE can reach 100%. Therefore, phosphorescent materials are widely used. However, the phosphorescent materials in the prior art have low efficiency and short service life when applied to organic light-emitting devices, and the stability of phosphorescent OLEDs also needs to be improved. Further analysis shows that phosphorescent OLEDs have a relatively long excited state lifetime, which in turn leads to exciton quenching of organic electroluminescence devices under high brightness, and serious efficiency decay. Therefore, how to provide an organic electroluminescence complex with long service life, high efficiency and low driving voltage is a problem that needs to be solved by those skilled in the art.

[0003] In view of this, the present application is proposed. SUMMARY

[0004] The present application aims to provide an organic electroluminescence complex, a preparation method thereof, a light-emitting layer material and an organic electroluminescence device. The organic electroluminescence complex provided by the embodiments of the present application has high air stability. The organic electroluminescence device formed thereby has the advantages of long service life, high efficiency and low driving voltage.

[0005] The present application is implemented as follows:

[0006] In a first aspect, the embodiments of the present application provide an organic electroluminescence complex selected from the following compounds represented by the following structural formula: M(L A )2(L B ), wherein M represents a metal, L A and L B are groups represented by the following structural formula:

[0007] ;

[0008] wherein R1, R2, R3, R4, R5, R6, Ar1and Ar2are each independently selected from any one of the functional group group consisting of -H, tritium, halogen, -CN, silyl, germyl, substituted or unsubstituted C1-C6alkyl, substituted or unsubstituted C3-C20cycloalkyl, substituted or unsubstituted C6-C10aryl, and substituted or unsubstituted 4-8 membered aromatic heterocyclyl;

[0009] X1-X8are each independently -CR X X R Y X1-X8are each independently -CR Y Y R Y X1-X8are each independently -CR Y Y X1-X8are each independently -CR Y Y when two R Y are present simultaneously, the two R X are the same or different, each independently selected from any one of the functional group group consisting of -H, tritium, halogen, -CN, silyl, germyl, substituted or unsubstituted C1-C6alkyl, substituted or unsubstituted C3-C20cycloalkyl, substituted or unsubstituted C6-C10aryl, and substituted or unsubstituted 4-8 membered aromatic heterocyclyl;

[0010] Ring A is present or absent, when present, is a 5-6 membered aromatic or aromatic heterocyclic ring, and is fused to the ring at any position;

[0011] m and n represent the maximum number of substitution on the ring, respectively, from no substitution to the corresponding substituent;

[0012] W is selected from any one of the functional group group consisting of O, S, Se, NR Y , CR Y R Y , SiR Y R Y , and GeR Y R Y at each occurrence, which are the same or different; when two R Y are present simultaneously, the two R Y are the same or different, each independently selected from any one of the functional group group consisting of -H, tritium, halogen, -CN, silyl, germyl, substituted or unsubstituted C1-C6alkyl, substituted or unsubstituted C3-C20cycloalkyl, substituted or unsubstituted C6-C10aryl, and substituted or unsubstituted 4-8 membered aromatic heterocyclyl;

[0013] Any of the aforementioned groups can form a cyclic group with each other or with the ring; i.e. R1and R2, R2and R3, R1and R3, R4and R5, Ar1and the ring, between multiple Ar1, Ar2and A ring, between multiple Ar2, between multiple R X , and between R X and the ring can form a cyclic group;

[0014] All hydrogens in the organic electroluminescent complex are each independently selected from protium or deuterium;

[0015] The heteroatom in the aromatic heterocyclic group includes any one or several of N, O and S.

[0016] In a second aspect, the present application provides a preparation method of the organic electroluminescent complex, comprising: synthesizing according to the following synthesis path:

[0017] .

[0018] In a third aspect, the present application provides a light-emitting layer material, comprising a host material and the organic electroluminescent complex according to the above embodiments.

[0019] In a fourth aspect, the present application provides an organic electroluminescent device, comprising a light-emitting layer formed by the light-emitting layer material according to the above embodiments.

[0020] The organic electroluminescent complex provided by the present application introduces a fluorene structure into a specific pyrimidine ring and modifies the structure. The nitrogen atom can act as an electron acceptor due to its strong electron affinity, promoting electron injection and transport. By introducing specific functional groups, the conjugation length and electron distribution of the molecule can be adjusted, thereby affecting the singlet-triplet energy level difference and the reverse intersystem crossing rate, and enhancing the spin-orbit coupling, thereby improving the luminous efficiency and stability of the light-emitting material. The introduction of the nitrogen atom not only helps to adjust the electron distribution, but also enhances the electron transport capability by changing the frontier orbital energy level of the molecule, and improves the air stability of the light-emitting material. Meanwhile, the organic electroluminescent device structure provided by the present application is matched, so that the organic electroluminescent device has the advantages of long service life, high efficiency and low driving voltage. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0022] Figure 1 NMR spectrum of the organic electroluminescent complex provided for the first embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely. The specific conditions are not specified in the embodiments, which are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, which are conventional products that can be purchased on the market.

[0024] In a first aspect, embodiments of the present application provide an organic electroluminescent complex selected from the group consisting of compounds represented by the following structural formulae: M(L A )2(L B ), wherein M represents a metal, L A and L B are groups represented by the following structural formulae:

[0025] ;

[0026] wherein R1, R2, R3, R4, R5, R6, Ar1and Ar2are each independently selected from any one of the group of functional groups consisting of -H, tritium, halogen, -CN, silyl, germyl, substituted or unsubstituted C1-C6alkyl, substituted or unsubstituted C3-C20cycloalkyl, substituted or unsubstituted C6-C10aryl, and substituted or unsubstituted 4- to 8-membered aromatic heterocyclyl.

[0027] X1-X8are each independently a -CR X group, and R X of X1-X8are each independently -H, tritium, halogen, -CN, silyl, germyl, substituted or unsubstituted C1-C6alkyl, substituted or unsubstituted C3-C20cycloalkyl, substituted or unsubstituted C6-C10aryl, and substituted or unsubstituted 4- to 8-membered aromatic heterocyclyl.

[0028] Ring A is present or absent, and when present, is a 5-6 membered aromatic or aromatic heterocyclic ring and is fused to the ring containing X1, X2, X3and X4. That is, Ring A can be absent, in which case Ar2is directly attached to the ring containing X1, X2, X3and X4. Ring A can also be present, and in this case, is a 5-6 membered aromatic or aromatic heterocyclic ring and is fused to the ring containing X1, X2, X3and X4.

[0029] m and n represent the maximum number of substitutions on the ring to which they are attached; that is, m and n are 0 when the ring to which they are attached is unsubstituted, meaning that Ar1and Ar2can be absent, i.e., they are not substituted on the ring to which they are attached. m and n also represent the maximum number of substituents on the ring to which they are attached; that is, Ar1and Ar2can be substituted on the ring to which they are attached with the maximum number of hydrogens.

[0030] W is the same or different at each occurrence and is selected from the group consisting of O, S, Se, NR Y , CR Y R Y , SiR Y R Y , and GeR Y R Yany one of the functional group group consisting of -H, deuterium, halogen, -CN, silane group, germanium group, substituted or unsubstituted C1-C6 alkyl group, substituted or unsubstituted C3-C20 cycloalkyl group, substituted or unsubstituted C6-C10 aryl group and substituted or unsubstituted 4-8 membered aromatic heterocyclic group. Y when two R Y are present simultaneously, the two R X are the same or different, each independently selected from any one of the functional group group consisting of -H, deuterium, halogen, -CN, silane group, germanium group, substituted or unsubstituted C1-C6 alkyl group, substituted or unsubstituted C3-C20 cycloalkyl group, substituted or unsubstituted C6-C10 aryl group and substituted or unsubstituted 4-8 membered aromatic heterocyclic group.

[0031] It should be noted that the heteroatoms in the aromatic heterocyclic group described above in the embodiments of the present application include any one or several of N, O and S.

[0032] Any of the aforementioned groups can form a cyclic group with each other or with the ring in which they are located; that is, R1 and R2, R2 and R3, R1 and R3, R4 and R5, Ar1 and the ring in which it is located, between multiple Ar1, Ar2 and the A ring, between multiple Ar2, between multiple R X each other, and R X and the ring in which they are located.

[0033] All hydrogens in the organic electroluminescent complex are independently selected from protium or deuterium; that is, the hydrogens in all groups in the organic electroluminescent complex can be conventional hydrogen (i.e., protium), or heavy hydrogen, or part of the hydrogens in all groups in the organic electroluminescent complex are conventional hydrogen (i.e., protium) and part are heavy hydrogen, or all are heavy hydrogen.

[0034] At present, the regulation mechanism of diketone ligand in iridium complex is not completely clear, and the research is still in the experimental dominant stage. Different structures of diketone ligand can affect the luminescent color and efficiency of phosphorescent material by adjusting the triplet energy level and excited state dynamics. However, factors such as the length, configuration and size of branched alkyl group will significantly affect the performance of the material, such as wavelength, half peak width, quantum yield, etc. In addition, for different host materials, how to achieve the best matching by regulating the structure of diketone ligand currently lacks systematic theoretical guidance, and usually needs a large number of experimental verification. Future research should further explore the relationship between structure and performance to achieve more efficient and stable phosphorescent material design.

[0035] The organic electroluminescent complex provided by the embodiment of the present application introduces a fluorene structure into a specific pyrimidine ring and modifies the structure. The nitrogen atom can act as an electron acceptor due to its strong electron affinity, which promotes electron injection and transport. By introducing specific functional groups, the conjugation length and electron distribution of the molecule can be adjusted, thereby affecting the singlet-triplet energy level difference and the reverse intersystem crossing rate, and enhancing the spin-orbit coupling, thereby improving the luminous efficiency and stability of the organic electroluminescent complex. The introduction of the nitrogen atom not only helps to adjust the electron distribution, but also enhances the electron transport capacity by changing the frontier orbital energy level of the molecule, and improves the air stability of the organic electroluminescent complex. At the same time, the organic electroluminescent device structure matching the embodiment of the present application further makes the OLED device have the advantages of long service life, high efficiency and low driving voltage.

[0036] Further, R1, R2, R3, R4, R5, R6, Ar1, Ar2, X1-X8 in R X and R Y may be the same or different, each of which is independently selected from any one of the functional group group consisting of -H, deuterium, tritium, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -Ge(Me)3, -Si(Me)3, substituted or unsubstituted C2-C6 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C10 aryl, and substituted or unsubstituted 4-8-membered aromatic heterocyclic group.

[0037] Further, R1, R2, R3, R4, R5, R6, Ar1, Ar2, R X and R Y are each independently selected from any one of the following groups:

[0038] -H, deuterium, tritium, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -Ge(Me)3, -Si(Me)3, methyl, ethyl, isopropyl, tert-butyl, n-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, tetrahydrofuran, pyrrolidine, thiolane, tetrahydropyran, phenyl, biphenyl, terphenyl, deuterated phenyl, di-deuterated phenyl, naphthyl, fluorenyl, phenanthryl, anthryl, indenyl, triphenylenyl, fluoranthenyl, furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, pyridyl, pyrazinyl, pyrimidinyl, benzofuranyl, benzothienyl, isobenzofuranyl, dibenzofuranyl, dibenzothienyl, benzimidazolyl, benzothiazolyl, benzoisothiazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, quinazolyl, quinoxalyl, carbazolyl, phenanthridyl, benzodioxolyl, and a functional group formed by any one of the following groups:

[0039] .

[0040] Further, M represents Ir; ring A represents phenyl; W represents any one of the following groups of functional groups: O, S, Se, Si(Me)2, Ge(Me)2, C(Me)2, NMe.

[0041] Further, the organic electroluminescent complex is selected from any one of the following compounds represented by the following structural formula:

[0042] .

[0043] The definitions of R1, R2, R3, R4, R5, R6, Ar1, Ar2, X1-X8 in the above structural formula are consistent with the aforementioned definitions.

[0044] More specifically, the organic electroluminescent complex is selected from any one of the following compounds represented by the following structural formula:

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090] .

[0091] In a second aspect, an embodiment of the present invention provides a method for preparing an organic electroluminescent complex, comprising: synthesizing according to the following synthesis path:

[0092] . The specific process is as follows:

[0093] (1) Under nitrogen protection, a compound of formula LA and an Ir salt, such as IrCl3·3H2O, are placed in a reaction system. A solvent, such as a mixed solution of ethylene glycol ethyl ether and purified water, is added. The reaction is refluxed under inert gas protection, and then cooled to room temperature. A precipitate is precipitated, which is filtered, rinsed with water, anhydrous ethanol, and petroleum ether, and dried in sequence. The bridged ligand compound of formula II shown is obtained.

[0094] (2) Weigh the intermediate compound of Formula II and a basic substance such as anhydrous potassium carbonate, add a solvent such as ethylene glycol ethyl ether, and then add the ligand of Formula LB. Under nitrogen protection, reflux the reaction, filter, wash with alcohol, and dry. Use dichloromethane as the solvent and perform silica gel column chromatography. Concentrate the filtrate to precipitate a solid to obtain the final product of Formula I.

[0095] In a third aspect, an embodiment of the present invention provides a light-emitting layer material, which includes a host material and the organic electroluminescent complex described in the above embodiment.

[0096] In a fourth aspect, an embodiment of the present invention provides an organic electroluminescent device. Generally speaking, an organic electroluminescent device includes a first electrode, a second electrode, and an organic material layer located between the electrodes. The organic material can be divided into multiple regions. For example, the organic material layer can include a hole transport region, a light-emitting layer, and an electron transport region. For example, an organic electroluminescent device provided by an embodiment of the present invention includes a first electrode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a second electrode arranged in sequence.

[0097] In a specific embodiment, a substrate can be used below the first electrode or above the second electrode. The substrate is made of glass or a polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. In addition, the substrate used for the display can also be provided with thin film transistors (TFTs).

[0098] The first electrode can be formed by sputtering or depositing the material used as the first electrode on the substrate. When the first electrode serves as an anode, transparent conductive oxide materials such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO) and any combination thereof can be used. In addition, the anode material can also be selected from materials and combinations thereof that facilitate hole injection other than the listed anode materials, including materials known to be suitable for anodes. When the first electrode serves as a cathode, metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag) and any combination thereof can be used. In addition to the cathode materials listed above, the cathode material can also be a material and a combination thereof that facilitates electron injection, including materials known to be suitable for cathodes.

[0099] The organic material layer can be formed on the electrode by vacuum thermal evaporation, spin coating, printing, etc. The compound used as the organic material layer can be an organic small molecule, an organic macromolecule, and a polymer, and combinations thereof. The hole transport zone is located between the anode and the light-emitting layer. The hole transport zone can be a single-layer structure hole transport layer (HTL), including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. The hole transport zone can also be a multi-layer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0100] The material of the hole transport layer can be selected from, but not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or conductive dopant-containing polymers such as polyphenylene vinylene, polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphor sulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), aromatic amine derivatives such as the compounds shown in HT-1 to HT-34 below; or any combination thereof.

[0101]

[0102] but not limited to the above-mentioned materials.

[0103] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more of the compounds of HT-1 to HT-34 described above, or one or more of the compounds of HI-1 to HI-3 described below; or one or more of the compounds of HT-1 to HT-34 described above doped with one or more of the compounds of HI-1 to HI-3 described below:

[0104] but not limited to the above-mentioned materials.

[0105] The OLED organic material layer can also include an electron transport zone between the light-emitting layer and the cathode. The electron transport zone can be a single-layer structure electron transport layer (ETL), including a single-layer electron transport layer containing only one compound and a single-layer electron transport layer containing multiple compounds. The electron transport zone can also be a multi-layer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0106] The electron transport layer material can be selected from, but not limited to, a combination of one or more of ET-1 to ET-57 listed below.

[0107] but not limited to the above materials.

[0108] The organic electroluminescent device can also include an electron injection layer between the electron transport layer and the cathode, and the electron injection layer material includes, but is not limited to, a combination of one or more of the following: LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, and Ca.

[0109] The organic electroluminescent device provided by the embodiments of the present application has a light-emitting layer formed by a specific doping material and a host material, and in combination with other layer materials, the organic electroluminescent device can effectively reduce the turn-on voltage, improve the efficiency, and improve the problem of low service life.

[0110] The features and properties of the present application are further described in detail below in conjunction with the embodiments.

[0111] Embodiment 1

[0112] The embodiments of the present application provide a preparation method of an organic electroluminescent complex (denoted as I-1), comprising:

[0113] (1) Synthesis of intermediate L AⅢ -1;

[0114]

[0115] Under the nitrogen protection system, compound 4-chloro-6-fluorobenzo[4,5]thieno[3,2-d]pyrimidine (CAS:2098009-57-3) (1.0 eq), 2-(4-(tert-butyl)naphthalen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (CAS:2217657-10-6) (1.0 eq), anhydrous potassium carbonate (3.0 eq) were weighed into the reaction system, toluene, anhydrous ethanol, pure water were added, Pd(PPh3)4 (0.02 eq) was added under nitrogen protection, and reflux was carried out at 100°C for 24h under nitrogen protection. After the reaction was completed, the liquid was separated, extracted with ethyl acetate, washed with saturated brine three times, and concentrated under reduced pressure. 400ml of dichloromethane was added for dissolution, and the solution was column chromatographed (200-300 mesh, 1050g) with DCM:PE=1:1 as the developing agent. The receiving liquid was spun until no liquid flowed out, and the compound of formula LAIII-1 was obtained (the yield was 49%). The intermediate compound of formula LAIII-1 was subjected to the following analysis tests:

[0116] HPLC purity: greater than 99.5%;

[0117] Mass spectrum: the test value was 386.29.

[0118] (2) Synthesis of intermediate L AⅡ -1;

[0119]

[0120] Under the nitrogen protection system, magnesium powder (5.0 eq), nickel bis(acetylacetonate) (0.1 eq) and 1,3-bis(diphenylphosphino)propane (0.1 eq) were weighed into the reaction bottle; then the reaction was replaced with nitrogen three times. Super dry tetrahydrofuran was added to the reaction bottle, and then compound LAIII-1 (1.0 eq), methyl o-bromobenzoate (CAS:610-94-6) (5.0 eq) were added to the reaction, respectively. After addition, the mixture was stirred at room temperature for 12 hours. After the reaction was completed, saturated ammonium chloride solution was used for quenching, and ethyl acetate was used for extraction. The extract was washed with saturated brine, dried with anhydrous sodium sulfate, and then the extract was removed by rotary evaporation. The crude product was column chromatographed (200-300 mesh, 800g) with DCM:PE=1:5 as the developing agent. The receiving liquid was spun until no liquid flowed out, and the compound of formula LAII-1 was obtained (the yield was 35%). The intermediate compound of formula LAII-1 was subjected to the following analysis tests:

[0121] HPLC purity: more than 99.5%;

[0122] Mass: test value is 502.34.

[0123] (3) Synthesis of intermediate L AⅠ -1;

[0124]

[0125] Under nitrogen protection system, intermediate compound formula LAII-1 (1.0 eq) was weighed, dissolved in anhydrous tetrahydrofuran, then methyl magnesium bromide (2.0 eq) was added, and the reaction was stirred at 50°C for 12 hours. After the reaction was completed, it was cooled to room temperature, then spin-dried, separated with dichloromethane and water, dried with magnesium sulfate, and then spin-dried. The crude product was developed by column chromatography (200-300 mesh, 750 g) with DCM:PE = 1:10 as the developing agent. The receiving liquid was spin-dried until no liquid flowed out, to obtain the compound formula LAI-1 (the yield was 46%). The intermediate compound formula L AⅠ -1 was subjected to the following analysis tests:

[0126] HPLC purity: more than 99.5%;

[0127] Mass: test value is 502.46.

[0128] (4) Synthesis of intermediate L A -1;

[0129]

[0130] Under nitrogen protection system, a dry reaction bottle was repeatedly vacuumed and filled with nitrogen three times. Intermediate compound formula L AⅠ -1 (1.0 eq) was weighed, and glacial acetic acid was added as a solvent, then concentrated sulfuric acid (10.0 eq) was slowly added dropwise. The reaction was heated to 80°C for 2 hours. After the reaction was completed, it was poured into 1L of ice water, and the precipitated solid was filtered and washed with water and methanol three times, to obtain the compound formula L A -1 (the yield was 69%). The intermediate compound formula L A -1 was subjected to the following analysis tests:

[0131] HPLC purity: more than 99.5%;

[0132] Mass: test value is 484.32.

[0133] (5) Synthesis of bridged ligand II-1;

[0134]

[0135] Under the nitrogen protection system, the ligand type LA-1 (3.0 eq) and IrCl3·3H2O (1.0 eq) are weighed and put into a reaction system, a mixed solution of ethylene glycol ether and pure water is added, and the system is refluxed for 27 hours under nitrogen protection, and then cooled to room temperature. A precipitate is separated out, which is extracted by filtration, washed with water, anhydrous ethanol and petroleum ether, and dried. The bridged ligand II-1 in dark red powder is obtained (the yield is 67%).

[0136] (6) the organic electroluminescent complex I-1;

[0137]

[0138] The bridged ligand II-1 (1.0 eq) is weighed, anhydrous potassium carbonate (10.0 eq) is added, ethylene glycol ether is added to the system, and nitrogen is replaced for three times. The compound of formula LB-1 (CAS: 872802-98-7) (3.0 eq) is added under nitrogen protection, and the system is refluxed for 25 hours under nitrogen protection. After cooling, the system is extracted by filtration, washed with alcohol, and dried. Dichloromethane is used as a solvent, and the filtrate is concentrated to obtain a solid. Finally, the organic electroluminescent complex I-1 is obtained (the yield is 33%).

[0139] The organic electroluminescent complex I-1 is subjected to the following analysis tests:

[0140] HPLC purity: greater than 99.5%;

[0141] Mass spectrum: the test value is 1370.59;

[0142] Elemental analysis: the calculated value is C, 69.22; H, 5.66; N, 4.09. The test value is C, 69.23; H, 5.67; N, 4.09.

[0143] The nuclear magnetic resonance hydrogen spectrum of the organic electroluminescent complex I-1 is shown in the following figure: Figure 1 .

[0144] The synthesis methods of other compounds are the same as above, which will not be described here. The present application also provides an organic electroluminescent device, which is made of the organic luminescent material, and more specifically, the organic luminescent material of the compound of formula I.

[0145] Device example 1

[0146] The present application also provides a preparation method of the organic electroluminescent device, and the specific process is as follows:

[0147] The organic electroluminescent devices provided by the embodiments of the present application are all prepared by high vacuum (<10 -7The devices were fabricated by thermal evaporation. The anode electrode was 1200 A indium tin oxide (ITO). The cathode consisted of 10 A Liq (lithium quinolate) followed by 1000 A Al. All devices were encapsulated with an epoxy sealed glass lid in a nitrogen glovebox (H20 and O2 < 1 ppm) immediately after fabrication and a desiccant was incorporated inside the package. The organic stack of the device examples consisted in order of: the ITO surface, 100 A of HT-1 as a hole injection layer (HIL); 400 A of HT-1 as a hole transport layer (HTL); 50 A of EBM as an electron blocking layer (EBL); 400 A of an emissive layer (EML) containing RH-1 as a red host and 3% of the emitter compound I-1; and 350 A of Liq (lithium quinolate) doped with 35% of ET-11 as an electron transport layer (ETL). Table 1 shows the thickness and materials of the functional layers.

[0148] Table 1 Functional layer materials and thickness

[0149]

[0150] The structures of the relevant starting materials are shown below:

[0151]

[0152] Device Examples 2-30 and Device Comparative Examples 1-4

[0153] Device Examples 2-30 and Device Comparative Examples 1-4 were all prepared as organic electroluminescent devices according to the preparation method of Device Example 1 described above, with the only difference being the change of the dopant material. Specifically, the dopant materials used in Device Examples 2-30 are shown in Table 2, and the structures of the dopant materials used in Device Comparative Examples 1-4 are shown below:

[0154]

[0155] Test Examples

[0156] The driving voltage, luminous efficiency and lifetime of the organic electroluminescent devices obtained from the above-described Device Examples and Device Comparative Examples were characterized at a brightness of 8000 (nits), and the test results are shown in Table 2 below: (the test results are normalized to Comparative Example 1).

[0157] Table 2 Test results

[0158]

[0159] As can be seen from Table 2, compared with the organic electroluminescent device prepared by using the organic electroluminescent complex provided by the embodiment of the present application as the light-emitting layer doping material, the organic electroluminescent device prepared by the comparative example, the present application promotes electron injection and transport by introducing and modifying the fluorene structure in the pyrimidine ring, utilizes the strong electron affinity of the nitrogen atom, adjusts the conjugate structure and electron distribution, optimizes the singlet-triplet energy level difference and the reverse intersystem crossing rate, and enhances the spin-orbit coupling, thereby improving the light-emitting efficiency and stability of the OLED device. Meanwhile, the nitrogen atom helps to improve the air stability and electron transport performance, so that the device has the advantages of high efficiency, low driving voltage and long service life.

[0160] The above embodiment only lists the effect data of the devices made by a part of structural formula, which is a representative sampling test. According to the experimental data, the overall data is not much different, and can represent the effect of other unlisted structures.

[0161] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An organic electroluminescent complex, characterized in that: It is selected from the compounds shown in the following structural formula: ； wherein, R1 and R3 are each independently selected from C1-C6 alkyl; R2 is hydrogen or CN; R4 and R5 are each independently selected from any one of methyl, F, deuterium and -CD3; R6 is hydrogen; X5-X8are each independently -CR X group, R X each independently is any one of -H, deuterium and C1-C6alkyl; W represents S; Ar1 represents any one of H, deuterium and C1-C6 alkyl; A is absent or only a phenyl ring, X1-X4are each independently -CR X group, R X each independently -H, C1-C6alkyl, -CD3, cyclopentyl and Ar2is any of H and C1-C6alkyl; m and n represent the maximum number of substituents on the ring to which they are attached.

2. An organic electroluminescent complex, characterized in that: The organic electroluminescent complex is selected from any one of the compounds shown in the following structural formula: 。 3. A light emitting layer material, characterized in that, It comprises a host material and the organic electroluminescent complex of claim 1.

4. An organic electroluminescent device, characterized by comprising It comprises a light-emitting layer formed by the light-emitting layer material of claim 3.

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