Organic electroluminescent material and preparation method and application thereof

Abstract

The invention provides an organic electroluminescent material and a preparation method and application thereof.The organic electroluminescent material has the following structure: M (LA) 2 (LB). According to the organic electroluminescent material, thiophene rings or furan rings of different structure combinations are connected to the specific naphthalene ring position, meanwhile, some any electronic groups are connected, and the specific naphthalene ring position is connected to the thiophene rings or furan rings of different structure combinations; according to the organic compound, the spatial configuration and the three-dimensional structure among molecules are changed, molecular orientation is set, steric hindrance is adjusted, and meanwhile, the device structure is matched, so that after the obtained organic compound is applied to the organic electroluminescent device, the device has the characteristics of long service life, high efficiency and low driving voltage.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic electroluminescent materials, and relates to an organic electroluminescent material, a preparation method thereof and an application thereof. Background Art

[0002] Organic semiconductor materials belong to new optoelectronic materials. Their large-scale origin dates back to 1977 when Hideki Shirakawa, A. Heeger and A. MacDiarmid jointly discovered doped polyethylene with a conductivity up to the level of copper. Subsequently, in 1987, C. Tang et al. of Kodak invented the organic small molecule light-emitting diode (OLED). OLED uses an organic thin film, which emits light when a voltage is applied to the device. OLED is becoming an increasingly concerned technology for applications such as flat panel displays, lighting and backlighting.

[0003] For various reasons, optoelectronic devices using organic materials have become increasingly popular. Many of the materials used to manufacture the devices are relatively inexpensive, so organic optoelectronic devices have the potential for cost advantages over inorganic devices. In addition, the inherent properties of organic materials (such as their flexibility) can make them more suitable for specific applications, such as manufacturing on flexible substrates. Examples of organic optoelectronic devices include organic light-emitting diodes / devices (OLEDs), organic phototransistors, organic photovoltaic cells and organic photodetectors. For OLEDs, organic materials can have performance advantages over conventional materials. For example, the wavelength of light emitted by the organic emission layer can usually be easily adjusted with appropriate dopants.

[0004] However, in the prior art, phosphorescent materials have low efficiency and short lifespan when applied to organic light-emitting devices. Therefore, how to provide an organic electroluminescent material with long lifespan, high efficiency and low driving voltage is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an organic electroluminescent material, a preparation method thereof and an application thereof. The organic electroluminescent material of the present invention connects thiophene rings or furan rings with different structural combinations at specific naphthalene ring positions, and at the same time connects some arbitrary electron groups, changes the spatial configuration and three-dimensional structure between molecules, sets the molecular orientation, adjusts the steric hindrance, and at the same time matches the device structure of the present invention, so that the obtained organic compound has the characteristics of long lifespan, high efficiency and low driving voltage after being used in an organic electroluminescent device.

[0006] To achieve the purpose of this invention, the present invention adopts the following technical solutions:

[0007] On the one hand, the present invention provides an organic electroluminescent material, and the organic electroluminescent material has the following structure: M(L A) 2 (L B );

[0008] wherein the ligand L A has the following structure:

[0009]

[0010] Ar 1 、Ar 2 、Ar 3 and Ar 4 are independently selected from -H, -D (deuterium), -T (tritium), -F, -CN, -CH 3 、-CD 3 、-CT 3 、-CF 3 、-CH 2 F、-CHF 2 、-Ge(Me) 3 、-Si(Me) 3 、any one of substituted or unsubstituted C2-C6 alkyl, substituted and unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C10 aryl, and substituted or unsubstituted 4- to 8-membered aromatic heterocyclic group;

[0011] and Ar 1 、Ar 2 、Ar 3 and Ar 4 respectively represent no substitution to maximum substitution on the ring where they are located;

[0012] X is O, S, Se, NR', CR'R", SiR'R", and GeR'R";

[0013] The ligand L B is any one of the following structures:

[0014]

[0015] wherein, Rb 1 -Rb 23 are independently selected from -H, -D (deuterium), -T (tritium), -F, -CN, -CH 3 、-CD 3 、-CT 3 、-CF 3 、-CH 2 F、-CHF 2 、-Ge(Me) 3 、-Si(Me) 3、any one of substituted or unsubstituted C2-C6 alkyl, substituted and unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C10 aryl, and substituted or unsubstituted 4- to 8-membered aromatic heterocyclic group;

[0016] and Rb 1 -Rb 23 Any group can form a cyclic group with each other or form a cyclic group with the ring where it is located;

[0017] The above L A and L B The atoms in the group can all be deuterated.

[0018] M is the metal Ir.

[0019] In the present invention, the C2-C6 can be C2, C3, C4, C5 or C6, the C3-C20 can be C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19 or C20, and the C6-C10 can be C6, C7, C8, C9 or C10.

[0020] In the above-mentioned substituted groups, the substituents are selected from hydrogen, deuterium, halogen group, cyano group, trifluoromethyl group, methyl group, ethyl group, n-propyl group, isopropyl group, butyl group, n-butyl group, isobutyl group, tert-butyl group, sec-butyl group, 1-methylbutyl group, 1-ethylbutyl group, pentyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, hexyl group, n-hexyl group, 1-methylpentyl group, 2-methylpentyl group, 4-methyl-2-pentyl group, 3,3-dimethylbutyl group, 2-ethylbutyl group, 1-methylhexyl group, phenyl group, naphthyl group, anthracenyl group, phenanthryl group, thienyl group, furyl group, pyrrolyl group, benzothienyl group, benzofuryl group, pyridyl group, indolyl group, cyclopentyl group, cyclohexyl group, adamantane or a substituent formed by connecting two or more of the above-mentioned substituents.

[0021] Preferably, L A is a ligand having any one of the following structures:

[0022]

[0023] R 1 -R 22 independently selected from -H, -D (deuterium), -T (tritium), -F, -CN, -CH 3 , -CD 3 , -CT 3 , -CF 3 , -CH 2 , -CHF 2 , -Ge(Me) 3 , -Si(Me)3 、 any one of substituted or unsubstituted C2-C6 alkyl, substituted and unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C10 aryl, and substituted or unsubstituted 4- to 8-membered aromatic heterocyclic group;

[0024] and R 1 -R 22 Any of the groups can form a cyclic group with each other or with the ring where they are located.

[0025] Preferably, the R 1 -R 22 and Rb 1 -Rb 23 are respectively selected from the following groups: -H, -D (deuterium), -T (tritium), -F, -CN, -CH 3 、-CD 3 、-CT 3 、-CF 3 、-CH 2 F、-CHF 2 、 silyl, germyl, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, tetrahydrofuranyl, pyrrolidinyl, thiacyclopentyl, tetrahydropyranyl, phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthryl, anthryl, indenyl, triphenylenyl, pyrenyl, quaterphenyl, perylenyl, chrysenyl, condensed quaterphenyl, fluoranthenyl, furyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, benzofuranyl, benzothienyl, isobenzofuranyl, dibenzofuranyl, dibenzothienyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzothiadiazolyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenanthridinyl or benzodioxolyl, etc., any one or a combination of at least two of these groups.

[0026] Preferably, the organic electroluminescent material is selected from any one of the following structures:

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[0094] In the present invention, the preparation process of the compound of formula I structure is as follows:

[0095]

[0096] Among them, L BB is the raw material of the above ligand L B when not coordinated. The definitions of other groups in the formula are the same as those described above and will not be elaborated herein.

[0097] The specific synthesis steps are as follows:

[0098] 1. Under nitrogen protection, the compound of formula L A structure and IrC1 3 ·3H 2 O are put into the reaction system, a mixed solution of ethylene glycol monoethyl ether and pure water is added, and the reaction is carried out at 120 °C under nitrogen protection. Then it is cooled to room temperature, and a precipitate is formed. The precipitate is filtered by suction and washed successively with water, absolute ethanol, and petroleum ether and then dried. The intermediate compound of formula II as shown is obtained.

[0099] 2. Weigh the intermediate compound of formula II and anhydrous potassium carbonate, add ethylene glycol monoethyl ether, and then add the ligand of formula L BB . Under nitrogen protection, the reaction is carried out at 120 °C, filtered by suction, washed with alcohol, and dried. Using dichloromethane as the solvent, silica gel column chromatography is carried out, and the filtrate is concentrated to precipitate a solid, obtaining the final product of the compound of formula I as shown.

[0100] On the other hand, the present invention provides an organic electroluminescent device, which includes a first electrode and a second electrode, and an organic material layer located between the electrodes. The organic material layer includes a light-emitting layer, and the doping material in the light-emitting layer includes the above-mentioned organic electroluminescent material.

[0101] Generally speaking, an organic electroluminescent device includes a first electrode and a second electrode, and an organic material layer located between the electrodes. The organic material can be further 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.

[0102] Preferably, the organic material layer further includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer, or an electron injection layer.

[0103] Preferably, the organic electroluminescent device includes an anode (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 cathode (second electrode) arranged in sequence. The doping material in the light-emitting layer includes the above-mentioned organic electroluminescent material.

[0104] In a specific embodiment, a substrate can be used under the first electrode or above the second electrode. The substrates are all glass or polymer materials with excellent mechanical strength, thermal stability, water resistance, and transparency. In addition, thin film transistors (TFTs) can also be provided on the substrate for display use.

[0105] The first electrode can be formed by sputtering or depositing a material used as the first electrode on the substrate. When the first electrode is used as an anode, oxide transparent conductive materials such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), etc., and any combination thereof can be used. In addition, the anode material can also be selected from materials and their combinations that contribute to hole injection other than the listed anode materials, including known materials suitable for use as an anode. When the first electrode is used 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), etc., and any combination thereof can be used. In addition to the listed cathode materials, the cathode material can also be a material and its combination that contribute to electron injection, including known materials suitable for use as a cathode.

[0106] The organic material layer can be formed on the electrode by methods such as vacuum thermal evaporation, spin coating, printing, etc. The compounds used as the organic material layer can be organic small molecules, organic macromolecules, and polymers, as well as combinations thereof. The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a single-layer 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 region 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).

[0107] The materials of the hole transport layer can be selected from, but not limited to, phthalocyanine derivatives such as CuPc, conductive polymers, or polymers containing conductive dopants such as poly(phenylene vinylene), polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives such as the compounds shown by HT-1 to HT-34 below; or any combination thereof.

[0108]

[0109]

[0110] However, it is not limited to the above several materials.

[0111] 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 adopt one or more of the above compounds of HT-1 to HT-34, or adopt one or more of the following compounds of HI-1 - HI-3; it can also adopt one or more of the compounds of HT-1 to HT-34 doped with one or more of the following compounds of HI-1 to HI-3:

[0112]

[0113] However, it is not limited to the above several materials.

[0114] The OLED organic material layer can also include an electron transport region between the light-emitting layer and the cathode. The electron transport region can be a single-layer 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 region 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).

[0115] In one aspect of the present invention, the electron transport layer material can be selected from, but not limited to, one or a combination of more than one of ET-1 to ET-57 listed below.

[0116]

[0117]

[0118]

[0119] However, it is not limited to the above several materials.

[0120] The device may further include an electron injection layer located between the electron transport layer and the cathode. The electron injection layer material includes, but is not limited to, one or a combination of more than one of the following listed: LiF, NaCl, CsF, Li 2 O, Cs 2 CO 3 , BaO, Na, Li, Ca.

[0121] Compared with the prior art, the present invention has the following beneficial effects:

[0122] The organic electroluminescent material of the present invention connects thiophene rings or furan rings with different structural combinations at specific naphthalene ring positions, and at the same time connects some arbitrary electron groups, changes the spatial configuration and three-dimensional structure between molecules, sets the molecular orientation, adjusts the steric hindrance, and at the same time matches the device structure of the present invention, so that when the compound is applied to an organic electroluminescent device, the starting voltage is reduced, the efficiency is improved, and the lifespan is increased.

[0123] Using the organic electroluminescent material described in the present invention as a doping material in the light-emitting layer of the organic electroluminescent device of the present invention can effectively reduce the turn-on voltage, improve the efficiency, and improve the problem of low lifespan of the obtained organic electroluminescent device. Brief Description of the Drawings

[0124] Figure 1 1H NMR spectrum of compound I-10.

[0125] Figure 2 1H NMR spectrum of compound I-1015. Detailed Description of the Invention

[0126] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0127] In addition, it should be noted that the numerical values given in the following examples are as accurate as possible. However, those skilled in the art understand that due to inevitable measurement errors and experimental operation problems, each number should be understood as an approximate value rather than an absolutely accurate numerical value.

[0128] Synthesis Example 1

[0129] This synthesis example provides an organometallic compound I-10, that is, the compound numbered I-10. The specific synthesis steps are as follows:

[0130]

[0131] Under a nitrogen protection system, weigh out compound 8-bromobenzofuro[2,3-c]pyridine (CAS: 1835734-80-9, 380 mmol), isobutylboronic acid (CAS: 84110-40-7, 418 mmol), and anhydrous potassium carbonate (1140 mmol) and put them into the reaction system. Add 2500 ml of toluene, 1250 mL of absolute ethanol, and 1250 mL of pure water. Under nitrogen protection, add Pd(PPh 3 ) 4 (7.6 mmol). Under nitrogen protection, reflux at 100 °C for 25 h. After the reaction is completed, separate the liquid, extract with ethyl acetate, and wash three times with saturated brine, then concentrate under reduced pressure. Add 400 ml of dichloromethane to dissolve, and subject the solution to column chromatography (200 - 300 mesh, 1250 g). The developing agent is DCM:PE volume ratio = 1:2. Spin the receiving solution until no liquid flows out to obtain the shown compound formula L AB -10 (59.03 g, yield 69%). Analyze and test the intermediate compound formula L AB -10 as follows:

[0132] HPLC purity: greater than 99.5%;

[0133] Mass spectrometry: The measured value is 225.28.

[0134]

[0135] Dissolve the compound formula L AB -10 (260 mmol) in methanol (150.0 mL). Slowly add bromine (150 mmol) at -60 °C. After adding, warm up to 20 °C and stir for 2 h. Then, add saturated sodium bicarbonate solution (400.0 mL) and water (200.0 mL) at 0 °C, stir for 5 minutes, extract 3 times with dichloromethane (500 mL), combine the organic layers, wash 2 times with saturated brine, dry over anhydrous sodium sulfate, and concentrate in vacuo to obtain the crude product. The crude product is purified by column chromatography (eluent: PE / EA = 50 / 1 - 10 / 1) to obtain the shown compound formula L AA-10 (24.42 g, yield 31%), the intermediate compound of formula L AA -10 was subjected to the following analytical tests:

[0136] HPLC purity: greater than 99.5%;

[0137] Mass spectrometry: measured value 303.20.

[0138]

[0139] Under a nitrogen protection system, weigh compound L AA -10 (80 mmol), 1-naphthaleneboronic acid (CAS: 13922-41-3, 88 mmol), anhydrous potassium carbonate (240 mmol) were placed into the reaction system, 1600 ml of toluene, 800 mL of absolute ethanol, and 800 mL of purified water were added. Under nitrogen protection, Pd(PPh 3 ) 4 (1.6 mmol) was added. Under nitrogen protection, the mixture was refluxed at 100 °C for 25 h. After the reaction was completed, liquid separation was carried out, and extraction was performed with ethyl acetate, followed by washing three times with saturated brine, and concentration under reduced pressure. 250 ml of dichloromethane was added to dissolve, and the solution was subjected to column chromatography (200 - 300 mesh, 700 g) with the eluent DCM:PE = 1:3. The receiving solution was rotated until no liquid flowed out, and the shown compound of formula L A -10 (21.91 g, yield 78%) was obtained. The intermediate compound of formula L A -10 was subjected to the following analytical tests:

[0140] HPLC purity: greater than 99.5%;

[0141] Mass spectrometry: measured value 351.37.

[0142]

[0143] Under a nitrogen protection system, weigh ligand of formula L A -10 (50.6 mmol), IrC1 3 ·3H 2 O (22 mmol) were placed into the reaction system, and a mixed solution of 480 ml of ethylene glycol monoethyl ether and 160 ml of purified water was added. The reaction was carried out at 120 °C for 28 h under nitrogen protection, then cooled to room temperature, and a precipitate was formed. The precipitate was filtered by suction and washed successively with water, absolute ethanol, and petroleum ether, and then dried. The bridged ligand II-10 (12.87 g, yield 63%) in the form of a dark red powder was obtained.

[0144]

[0145] Weigh the bridging ligand II-10 (5.5 mmol), add anhydrous potassium carbonate (55 mmol), then add 190 ml of ethylene glycol monoethyl ether to the system, displace nitrogen three times, and add the compound of formula L B -10 (CAS: 872802-98-7) (16.5 mmol) under nitrogen. React at 120 °C for 23 h under nitrogen protection, cool down, filter by suction, wash with alcohol, and dry. Use dichloromethane as the solvent and perform column chromatography on neutral alumina. Concentrate the filtrate to precipitate a solid, and finally obtain the organophosphorus luminescent material shown in formula I-10 (3.40 g, with a yield of 28%);

[0146] Perform the following analytical tests on the organometallic compound of formula I-10:

[0147] HPLC purity: greater than 99.5%;

[0148] Mass spectrometry: The measured value is 1104.75;

[0149] Elemental analysis: The calculated values are C, 68.51; H, 5.75; N, 2.54; O, 5.79.

[0150] The measured values are C, 68.45; H, 5.80; N, 2.61; O, 5.82;

[0151] 1 H NMR (400 MHz, chloroform-d) δ 8.48 (d, 2H), 8.02–7.86 (m, 8H), 7.82 (dd, 2H), 7.76–7.69 (m, 2H), 7.57–7.48 (m, 2H), 7.45–7.31 (m, 4H), 7.15 (dd, 2H), 5.65 (dd, 1H), 2.76 (pd, 1H), 2.57 (d, 4H), 2.48 (pd, 1H), 1.85 (dp, 2H), 1.63–1.39 (m, 8H), 0.89 (t, 12H), 0.84 (d, 12H).

[0152] Synthesis Example 2

[0153] This synthesis example provides an organometallic compound of formula I-1015, that is, the compound numbered as formula I-1015. The specific synthesis steps are as follows:

[0154]

[0155] Among them, the synthesis method of formula II-1015 is the same as that described in Example 1 and will not be elaborated here.

[0156] Weigh the bridging ligand of formula Ⅱ-1015 (5.5 mmol), add anhydrous potassium carbonate (55 mmol), then add 230 ml of ethylene glycol monoethyl ether to the system, displace nitrogen three times, and add the compound of formula L B -1015 (CAS: 98-98-6) (33 mmol) under nitrogen. Under nitrogen protection, reflux for 26 h, cool down, filter by suction, wash with alcohol, and dry. Use dichloromethane as the solvent and carry out column chromatography on neutral alumina. Concentrate the filtrate to precipitate solids, and finally obtain the organophosphorus luminescent material shown in formula Ⅰ-1015 (2.68 g, with a yield of 24%);

[0157] Perform the following analytical tests on the organometallic compound of formula Ⅰ-1015:

[0158] HPLC purity: greater than 99.5%;

[0159] Mass spectrometry: The measured value is 1015.46;

[0160] Elemental analysis: The calculated values are C, 66.25; H, 4.37; N, 4.14; O, 6.30.

[0161] The measured values are C, 66.16; H, 4.42; N, 4.21; O, 6.38;

[0162] 1 H NMR (400 MHz, chloroform-d) δ 8.74 (dd, 1H), 8.48 (d, 2H), 8.14 (dd, 1H), 8.06–7.99 (m, 2H), 7.97–7.86 (m, 7H), 7.82 (dd, 2H), 7.76–7.69 (m, 2H), 7.57–7.50 (m, 2H), 7.46 (td, 1H), 7.43–7.31 (m, 4H), 7.15 (dd, 2H), 2.57 (d, 4H), 1.85 (dp, 2H), 0.84 (d, 12H).

[0163] The synthesis methods of other compounds are the same as the above, and will not be elaborated one by one here. The mass spectrometry or molecular formulas of other synthesis examples are shown in Table 1 below:

[0164] Table 1

[0165]

[0166]

[0167] The synthesis methods of other compounds are the same as the above, and will not be elaborated one by one here.

[0168] Device Example 1

[0169] Device Fabrication

[0170] All example devices were fabricated by thermal evaporation in a high vacuum (< 10 -7 Torr). The anode electrode is indium tin oxide (ITO). The cathode consists of Liq (lithium 8-hydroxyquinoline) and subsequently Al. All devices were immediately encapsulated with a glass lid sealed with epoxy resin in a nitrogen glove box (H 2 2O and O 2 < 1 ppm) after fabrication, and a desiccant was incorporated inside the package. The organic stack of the device examples consists, in sequence, of: the ITO surface, HT-15 of as the hole injection layer (HIL); HT-15 of as the hole transport layer (HTL); EBM of as the electron blocking layer (EBL); an emission layer (EML) of containing RH-01 as the red host and 3% of the emitter type I-1 compound; and Liq (lithium 8-hydroxyquinoline) of doped with 35% of ET-15 as the electron transport layer (ETL). Table 2 shows the thickness and materials of the device layers.

[0171] Table 2: Device layer materials and thickness

[0172]

[0173] Device Examples 2 - 30

[0174] Referring to the method of Device Example 1 above, the only difference is that the doping material I-1 was replaced with I-10, I-134, I-189, I-211, I-276, I-355, I-398, I-402, I-449, I-481, I-528, I-594, I-622, I-666, I-707, I-794, I-847, I-870, I-909, I-926, I-955, I-979, I-996, I-1015, I-1041, I-1075, I-1114, I-1143, I-1176, respectively.

[0175] Device Comparative Examples 1 - 4

[0176] Organic light-emitting devices were prepared according to the same method as in Device Example 1, except that the doping compound I-1 in Device Example 1 was replaced with the comparative compound 1 - 4 structures, respectively.

[0177] The structures used are as follows:

[0178]

[0179] The driving voltage, luminous efficiency and lifetime of the organic electroluminescent devices obtained from the above device examples and device comparative examples were characterized at a brightness of 8000 (nits), and the test results are shown in Table 3 below.

[0180] Table 3

[0181]

[0182]

[0183] As can be seen from Table 3, compared with the organic electroluminescent devices prepared by using the comparative examples, for the organic electroluminescent devices prepared by using the compound provided by the present invention as the doping material of the light-emitting layer, the present invention selects specific ligand compounds, by connecting thiophene rings or furan rings with different structural combinations at specific naphthalene ring positions, and at the same time connecting some arbitrary electron groups, to change the intermolecular spatial configuration and three-dimensional structure, set the molecular orientation, adjust the steric hindrance, and at the same time match the device structure of the present invention, so that the OLED device has the advantages of long lifetime, high efficiency and low driving voltage.

[0184] The applicant declares that the present invention uses the above examples to illustrate the process method of the present invention, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of the raw materials selected by the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. An organic electroluminescent material, characterized in that: The organic electroluminescent material has the following structure: A )2(L B ); The ligand L A The structure is as follows: Ar1, Ar2, Ar3 and Ar4 are independently selected from any one of -H, -D (deuterium), -T (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; and Ar1, Ar2, Ar3 and Ar4 represent no substitution to maximum substitution in the ring respectively; X is O, S, Se, NR', CR'R", SiR'R" and GeR'R"; Ligand L B Has any of the following structures: Among them, Rb1-Rb 23 Independently selected from any one of -H, -D (deuterium), -T (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; And Rb1-Rb 23 Any groups can form a cyclic group with each other or with the ring in which they are located; The above L A and L B All atoms in the group can be deuterated. M is metal Ir.

2. The organic electroluminescent material according to claim 1, characterized in that: The substituents in the substituted group are selected from hydrogen, deuterium, halogen, cyano, trifluoromethyl, methyl, ethyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, 1-methylhexyl, phenyl, naphthyl, anthracenyl, phenanthrenyl, thienyl, furanyl, pyrrolyl, benzothienyl, benzofuranyl, pyridyl, indolyl, cyclopentanyl, cyclohexanyl, adamantane or a substituent in which two or more of the substituents shown above are connected.

3. The organic electroluminescent material according to claim 1, characterized in that: L A is a ligand having any of the following structures: R1-R 22 Independently selected from any one of -H, -D (deuterium), -T (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; And R1-R 22 Any groups may form a cyclic group with each other or with the ring in which they are located.

4. The organic electroluminescent material according to claim 1 or 3, characterized in that: The R1-R 22 and Rb1-Rb 23 are selected from the following groups: -H, -D (deuterium), -T (tritium), -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, silanyl, germanyl, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, tetrahydrofuranyl, pyrrolidinyl, thiolanyl, tetrahydropyranyl, phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, triphenylene, pyrenyl, naphthyl, peryl, chrysene , fused tetraphenyl, fluoranthene, furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, pyridinyl, pyrazinyl, pyrimidinyl, pyridazinyl, benzofuranyl, benzothienyl, isobenzofuranyl, dibenzofuranyl, dibenzothienyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, quinazolinyl, quinoxalinyl, carbazolyl, phenanthridinyl or benzodioxolyl groups or a combination of at least two thereof.

5. The organic electroluminescent material according to claim 1, characterized in that: The organic electroluminescent material is selected from any one of the following structures:

6. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises a first electrode, a second electrode, and an organic material layer between the electrodes, wherein the organic material layer comprises a light-emitting layer, and the doping material in the light-emitting layer comprises the organic electroluminescent material according to any one of claims 1 to 5.

7. The organic electroluminescent device according to claim 6, characterized in that: The organic material layer further includes at least one of a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer or an electron injection layer.

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