Organic electroluminescent doping material and organic electroluminescent device

Abstract

The invention provides an organic electroluminescent doping material and an organic electroluminescent device, and the organic electroluminescent doping material has a structure shown in a formula I. After the organic electroluminescent doping material is used for the organic electroluminescent device, the starting voltage of the device is reduced, the luminous efficiency of the device is improved, and the service life of the device is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic devices and relates to an organic electroluminescent doping material and an organic electroluminescent device. Background Art

[0002] Organic Light-Emitting Diode (OLED), also known as organic electric laser display or organic light-emitting semiconductor, refers to the phenomenon that organic semiconductor materials and luminescent materials emit light through carrier injection and recombination under the drive of an electric field. OLED is an organic electroluminescent device composed of relatively special organic materials. It can be divided into four types according to its structure, namely single-layer devices, double-layer devices, three-layer devices and multi-layer devices. Among them, the performance of the multi-layer structure is a relatively good structure, which can play the role of each level very well. The light-emitting layer can also be composed of a multi-layer structure. Since each emitting layer is independent of each other, it can be optimized separately. Therefore, this structure can give full play to the role of each organic layer and greatly improve the flexibility of device design.

[0003] The most important factor determining the luminous efficiency of organic EL devices is the luminescent material. Two generations of luminescent materials have been developed, and fluorescent materials have been widely used to date. However, first-generation fluorescent materials utilize singlet excitons, resulting in low internal quantum efficiencies, reaching a maximum of only 25%. Second-generation phosphorescent materials utilize triplet excitons, achieving a theoretical efficiency of 100%.

[0004] However, existing phosphorescent materials used in organic light-emitting devices suffer from low efficiency and short lifespan. 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] In response to the shortcomings of the prior art, the present invention aims to provide an organic electroluminescent dopant material and an organic electroluminescent device. By introducing a carbazole group into the ligand, the present invention imparts a rigid planar conjugated structure to the compound, improving the intermolecular symmetrical dipole moment and simultaneously improving the material's phosphorescence quantum efficiency and electroluminescence efficiency. Furthermore, the carbazole aromatic structure is modified with groups such as alkyl chains, cycloalkyl groups, aryl groups, and heteroalkyl groups, significantly enhancing the thermal and photostability of the structure. This results in the resulting organic compound, when used in an organic electroluminescent device, reducing the device's startup voltage and increasing the device's luminous efficiency and lifetime.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In one aspect, the present invention provides an organic electroluminescent dopant material having a structure shown in Formula I:

[0008]

[0009] X is one of N, O, S, Si, Ge, C or Se;

[0010] R1-R8 are each independently selected from -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, substituted or unsubstituted C2-C24 alkyl, substituted or unsubstituted C3-C24 cycloalkyl, substituted or unsubstituted C6-C24 aryl and substituted or unsubstituted 4-24 membered heterocyclyl;

[0011] R9-R 25 Each is independently selected from any one of -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, substituted or unsubstituted C2-C24 alkyl, substituted or unsubstituted C3-C24 cycloalkyl, substituted or unsubstituted C6-C24 aryl and substituted or unsubstituted 4-24 membered heterocyclyl;

[0012] R1-R 25 Each of them exists independently or at least one of them forms a substituted or unsubstituted C3-C24 aliphatic ring, a substituted or unsubstituted C6-C24 aromatic ring, a substituted or unsubstituted C4-C24 aromatic heterocycle, or a substituted or unsubstituted C10-C24 condensed ring with other substituents on the ring;

[0013] The substituents in the substituted group are selected from one or a combination of at least two of -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3;

[0014] The heteroatom in the heterocyclic group is at least one of N, O or S;

[0015] The hydrogen in formula I is not substituted by deuterium, partially substituted by deuterium, or completely substituted by deuterium;

[0016] D stands for deuterium, T stands for tritium, and Me stands for methyl.

[0017] More preferably, X is selected from O or S.

[0018] Preferably, R1-R8 are each independently selected from any one or a combination of at least two of the following groups: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, tetrahydrofuran, thiolane, tetrahydropyran, phenyl, Biphenyl, deuterated phenyl, dideuterated phenyl, terphenyl, naphthyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, triphenylene, pyrenyl, naphthacene, perylene, chrysene, fused tetraphenyl, fluoranthenyl, carbazolyl, furyl, thienyl, imidazolyl, thiazolyl, pyridyl, pyrimidinyl, benzofuranyl, benzothienyl, isobenzofuranyl, dibenzofuranyl, dibenzothienyl, benzimidazolyl, benzothiazolyl, quinolyl, isoquinolyl, or the following substituents;

[0019]

[0020] Where * represents the attachment site of the group.

[0021] Preferably, R9-R 25 Each independently selected from any one or a combination of at least two of the following groups: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, tetrahydrofuran, thiolane, tetrahydropyran, Phenyl, biphenyl, deuterated phenyl, dideuterated phenyl, terphenyl, naphthyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, triphenylene, pyrenyl, naphthacene, perylene, chrysene, fused tetraphenyl, carbazolyl, fluoranthenyl, furanyl, thienyl, imidazolyl, pyrazolyl, thiazolyl, triazinyl, pyridyl, pyrazinyl, pyrimidinyl, benzofuranyl, benzothienyl, dibenzofuranyl, dibenzothienyl, benzodioxolyl, or the following substituents;

[0022]

[0023] Where * represents the attachment site of the group;

[0024] R' is independently selected from any one or a combination of at least two of -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, biphenyl, deuterated phenyl, dideuterated phenyl, naphthyl, benzofuranyl, benzothiophenyl, furyl, thienyl, dibenzofuranyl or dibenzothiophenyl;

[0025] Preferably, R1-R 25 At least one of the substituents forms a cyclopentyl group, a cyclohexyl group, a benzene ring, a naphthalene ring, a benzofuranyl group, a benzothiophenyl group, a furyl group, a thiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group or a combination of at least two of the above groups with other substituents on the ring.

[0026] Further preferably, the organic electroluminescent doping material is any one of the following compounds:

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068] In the present invention, the preparation process of the compound of formula I is as follows:

[0069]

[0070] The definitions in the above formula are consistent with those mentioned above and will not be repeated here.

[0071] In another aspect, the present invention provides an organic electroluminescent device comprising an anode, a cathode, and an organic material layer disposed between the anode and the cathode, wherein the organic material layer comprises at least one of the organic electroluminescent doping materials described above.

[0072] Preferably, the organic material layer includes a light-emitting layer, the light-emitting layer includes a host material and a doping material, and the doping material includes at least one of the organic electroluminescent doping materials described above.

[0073] 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.

[0074] Preferably, the organic electroluminescent device comprises an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode arranged in sequence.

[0075] Generally speaking, an organic electroluminescent device includes a first electrode (anode) and a second electrode (cathode), as well as an organic material layer located between the electrodes. This organic material layer 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.

[0076] 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).

[0077] 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.

[0078] The organic material layer can be formed on the electrode by vacuum thermal evaporation, spin coating, printing and other methods. The compound used as the organic material layer can be an organic small molecule, an organic macromolecule and a polymer, and a combination thereof. The hole transport region is located between the anode and the light-emitting layer. The hole transport region can be a hole transport layer (HTL) with a single-layer structure, including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. The hole transport region can also be a multilayer structure including at least one layer of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0079] The material of the hole transport layer can be selected from, but not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), aromatic amine derivatives such as the compounds shown in HT-1 to HT-34 below; or any combination thereof.

[0080]

[0081]

[0082]

[0083] But it is not limited to the above materials.

[0084] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more compounds from HT-1 to HT-34 above, or one or more compounds from HI-1 to HI-3 below. Alternatively, one or more compounds from HT-1 to HT-34 can be doped with one or more compounds from HI-1 to HI-3 below:

[0085]

[0086] But it is not limited to the above materials.

[0087] The OLED organic material layer may further include an electron transport region between the light emitting layer and the cathode.

[0088] The light-emitting layer may include a luminescent dye (i.e., a dopant) that can emit light at different wavelengths, and may also include a host material. The light-emitting layer may be a monochromatic light-emitting layer that emits a single color, such as red, green, or blue. Multiple monochromatic light-emitting layers of different colors may be arranged in a planar pattern according to a pixel pattern, or they may be stacked together to form a multi-color light-emitting layer. When light-emitting layers of different colors are stacked together, they may be separated from each other or connected to each other. The light-emitting layer may also be a single-color light-emitting layer that can simultaneously emit different colors, such as red and green.

[0089] Depending on the technology, the luminescent layer material can include phosphorescent electroluminescent materials, thermally activated delayed fluorescent materials, and other materials. An OLED device can employ a single luminescence technology or a combination of multiple technologies. These different luminescent materials, categorized by technology, can emit the same or different colors of light.

[0090] The compound of formula I of the present invention is used as a doping material in the light-emitting layer.

[0091] 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).

[0092] In one aspect of the present invention, the electron transport layer material can be selected from, but not limited to, one or more combinations of ET-1 to ET-57 listed below.

[0093]

[0094]

[0095]

[0096]

[0097]

[0098] But it is not limited to the above materials.

[0099] 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 more combinations of the following: LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, and Ca.

[0100] Compared with the prior art, the present invention has the following beneficial effects:

[0101] By adjusting different L A The structure of the ligand (i.e. the ligand on the left in formula I) changes some electrons and groups, etc., changes the molecular space structure, improves the spin-orbit coupling effect of the luminescent molecule, makes it conducive to the generation of phosphorescence, enhances its quantum efficiency, and at the same time B The ligand (i.e., the ligand on the right side of Formula I) is further introduced with a carbazole group. As a result, compared with the comparative example compound, the compound of the present invention has a better rigid planar conjugated structure, improves the intermolecular symmetrical dipole moment, and simultaneously improves the phosphorescence quantum efficiency and electroluminescence efficiency of the material. At the same time, the aromatic carbazole structure is modified with groups such as alkyl chains, cycloalkyl groups, aryl groups, and heteroalkyl groups, which greatly enhances the thermal stability and photostability of the structure. As a result, the organic electroluminescent device prepared using the compound of the present invention as a doping material for the light-emitting layer has a significantly lower driving voltage and significantly improved luminous efficiency and life compared with the organic electroluminescent device prepared in the comparative example. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] Figure 1 This is the NMR spectrum of the compound of structural formula I-76. DETAILED DESCRIPTION

[0103] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0104] Example 1

[0105] This synthesis example provides an organometallic compound I-76, i.e., compound numbered I-76. The specific synthesis steps are as follows:

[0106]

[0107] Under nitrogen protection, 2-(6-chlorodibenzo[b,d]furan-4-yl)pyridine (CAS: 2888618-84-4, 1.0eq), diboronic acid pinacol ester (1.5eq), X-Phos (0.12eq), palladium acetate (0.02eq), potassium acetate (3eq) and dioxane were added to the reaction system in sequence. N2 was replaced three times and N2 was protected. The mixture was heated and stirred at 100°C overnight. After the reaction was completed, the mixture was filtered through celite and anhydrous magnesium sulfate, washed twice with ethyl acetate, and the organic phase was collected and concentrated under reduced pressure to obtain a crude product intermediate of formula L BⅢ -76 is used directly in the next step.

[0108]

[0109] Under nitrogen protection system, weigh compound 1-bromo-2-nitrobenzene (CAS: 577-19-5, 1.0eq), intermediate formula L BⅢ -76 (1.2 eq) and anhydrous potassium carbonate (3.0 eq) were placed in the reaction system, and toluene, anhydrous ethanol, and purified water were added. Pd(PPh3)4 (0.02 eq) was added under nitrogen protection. After the addition was completed, the mixture was refluxed at 100°C for 26 hours under nitrogen protection, and then cooled to 25°C. After the reaction was cooled, the mixture was extracted with ethyl acetate, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The crude product was subjected to column chromatography (200-300 mesh) with a developing agent of EA:PE = 1:10 to remove impurities. The receiving solution was vortexed until no liquid flowed out and dried under vacuum to obtain the intermediate compound L shown. BⅡ -76 (yield 68%), its HPLC purity was greater than 99.5%.

[0110] Mass spectrometry test value: 366.42.

[0111]

[0112] Under nitrogen protection system, weigh compound L BⅡ -76 (1.0 eq) was dissolved in o-dichlorobenzene, and triphenylphosphine (1.2 eq) was added under nitrogen protection. The mixture was refluxed for 24 h. After the reaction was completed, the solvent was dried by spin-drying. The crude product was subjected to column chromatography (200-300 mesh) with a developing solvent of EA:PE = 1:15 to remove impurities. The receiving solution was vortexed until no liquid flowed out and vacuum dried to obtain the intermediate compound L shown in FIG. BⅠ -76 (yield 59%) with HPLC purity greater than 99.5%.

[0113] Mass spectrometry test value: 334.37.

[0114]

[0115] Under nitrogen protection system, weigh compound intermediate L BⅠ -76 (1.0eq), bromobenzene (CAS: 108-86-1) (1.2eq), sodium tert-butoxide (2.0eq) were placed in the reaction system, toluene was added, and Pd2(dba)3 (0.04eq) and PPh3 (0.1eq) were added under nitrogen protection. After the addition was completed, the mixture was refluxed at 100°C for 24h under nitrogen protection, and then cooled to 25°C. After the reaction was cooled, the mixture was extracted with ethyl acetate, washed three times with saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The crude product was subjected to column chromatography (200-300 mesh) with a developing agent of EA:PE = 1:8 to remove impurities. The receiving solution was vortexed until no liquid flowed out and dried under vacuum to obtain the intermediate L shown as the compound. B -76 (yield 76%) with HPLC purity greater than 99.5%.

[0116] Mass spectrometry test value: 410.35.

[0117]

[0118] Under nitrogen protection system, weigh the ligand L A -76 (5-methyl-2-phenylpyridine) (CAS: 3256-88-0) (2.4 eq) and IrCl3·3H2O (1.0 eq) were placed in the reaction system, and a mixed solution of ethylene glycol ethyl ether and purified water was added. The mixture was refluxed under nitrogen for 28 hours and then cooled to room temperature. A precipitate was precipitated, which was filtered, rinsed with water, anhydrous ethanol, and petroleum ether in sequence, and dried.

[0119] The indicated bridged ligand III-76 was obtained in 63% yield.

[0120]

[0121] Intermediate Formula III-76 (1.0 eq) was weighed, and silver trifluoromethanesulfonate (2.5 eq) was added. Dichloromethane and methanol were then added to the system. Under nitrogen, the mixture was refluxed for 26 hours. The mixture was cooled to room temperature, and the filtrate was concentrated by column chromatography (short column) until a solid precipitated. The iridium complex intermediate Formula II-76 shown was obtained (yield 86%).

[0122]

[0123] Weigh the intermediate II-76 (1.0eq) and add the ligand L B -76 (2.5 eq), then add anhydrous ethanol to the system, reflux under nitrogen for 36 hours, filter, wash with ethanol, and dry. Use dichloromethane as the solvent, perform silica gel column chromatography, concentrate the filtrate to precipitate the solid, and obtain the final compound shown in formula I-76 (yield 35%).

[0124] The organometallic compound I-76 was subjected to the following analytical tests:

[0125] HPLC purity: greater than 99.5%;

[0126] The mass spectrometry test value was 938.48.

[0127] Elemental analysis: Found values are C, 67.88; H, 3.99; N, 5.98; O, 1.72.

[0128] The H NMR spectrum of compound I-76 is as follows Figure 1 shown.

[0129] The synthesis methods of other compounds are the same as those described above and are not described in detail here.

[0130] The present invention also provides an organic electroluminescent device, which is made of the organic light-emitting material, more specifically, made of the organic light-emitting material of the compound of chemical formula I.

[0131] Device Example 1

[0132] Compound I-1 prepared in the present invention was selected as a phosphorescent material with a doping ratio of 5% to prepare an OLED device. The specific preparation method is as follows:

[0133] (1) A glass plate coated with an ITO transparent conductive layer was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol (volume ratio 1:1), baked in a clean environment until the water was completely removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0134] (2) Place the glass substrate with the anode in a vacuum chamber and evacuate to 1×10 -5 ~9×10 -3 Pa, vacuum evaporation HI-3 as a hole injection layer on the above-mentioned anode layer film at a deposition rate of 0.1 nm / s, with a total deposition thickness of 10 nm; then evaporation of the first hole layer HT-5 at a deposition rate of 0.1 nm / s to a thickness of 60 nm; then evaporation of the electron blocking layer EB-1 at a deposition rate of 0.1 nm / s to a thickness of 5 nm;

[0135] (3) Vacuum evaporating an EML on the hole transport layer as the light-emitting layer of the device. The EML includes a host material GH-1 and a dopant material I-1 of the present invention, with a doping concentration of 5% by mass, to form an organic light-emitting layer of the device. The evaporation rate is 0.2 nm / s, and the total film thickness is 30 nm.

[0136] (4) ET-15:LiQ with a mass ratio of 1:1 was evaporated on the hole blocking layer as the electron transport material of the device electron transport layer. The evaporation rate was 0.1 nm / s and the total film thickness was 30 nm.

[0137] (5) LiF with a thickness of 1 nm was vacuum-evaporated onto the electron transport layer as an electron injection layer, and an Al layer with a thickness of 150 nm was deposited as the device cathode. After packaging, an OLED device was obtained. The performance and luminescence characteristics of the resulting device were tested using a Keithley 2400 source measurement unit and a CS-2000 spectroradiometer to evaluate the driving voltage, lifetime, and luminous efficiency.

[0138] The structure used is as follows:

[0139]

[0140] Device Comparative Examples 1-6

[0141] An organic electroluminescent device was prepared in the same manner as in Device Example 1, except that the doping compound I-1 in Device Example 1 was replaced by the structural compounds of Comparative Examples 1-6, respectively.

[0142]

[0143] The prepared organic electroluminescent device was subjected to the same test as in Example 1. The results are shown in Table 1.

[0144] Device Examples 2-48

[0145] The method of the device embodiment 1 is referred to above, except that the doping material I-1 is replaced by the corresponding compounds in Table 1.

[0146] The driving voltage, luminous efficiency and lifespan of the organic electroluminescent devices obtained from the above device examples and device comparative examples were characterized at a brightness of 8000 (nits). The test results are shown in Table 1 below.

[0147] Table 1

[0148]

[0149]

[0150] By comparing the comparative examples 1-6 with the organometallic compounds of the present invention, it can be seen that L B The ligand is introduced into the dibenzofuran by reintroducing a carbazole type group, so that the compound of the present invention is compared with the comparative example compound, and the structural compound of the present invention has a better rigid planar conjugated structure, which can effectively suppress the π-π stacking between molecules and reduce the energy level transition loss. At the same time, it can optimize the HOMO and LUMO energy levels, induce the electronic charge transfer excited state, enhance the spin-orbit coupling, increase the transition dipole moment, greatly enhance the material luminous efficiency and reduce its turn-on voltage at the same time. At the same time, the carbazole aromatic structure is modified by the alkyl chain, which greatly enhances the thermal stability and light stability of the structure, so that its service life is significantly increased. As can be seen from the above table, the organic electroluminescent device prepared by the compound of the present invention as the light-emitting layer doping material is significantly reduced in driving voltage compared with the organic electroluminescent device prepared by the comparative example, and the luminous efficiency and life are significantly improved.

[0151] By comparing the comparative examples 1-6 with the organometallic compounds of the present invention, it can be seen that by adjusting different L AThe structure of the ligand changes some electrons and groups, etc., changes the molecular spatial structure, improves the spin-orbit coupling effect of the luminescent molecule, makes it conducive to the generation of phosphorescence, enhances its quantum efficiency, and makes the compound of the present invention used as a doping material for the light-emitting layer. The organic electroluminescent device prepared therefrom has a significantly lower driving voltage, and a significantly improved luminous efficiency and life compared with the organic electroluminescent device prepared in the comparative example, and these figures are all beyond any value attributable to experimental errors.

[0152] Specifically, compared with the compound of comparative example 3, the compound of structure Example Ⅰ-87 of the present invention simply replaces the -SiMe3 group of the dual ligand with a -Me group, which directly affects the carrier mobility, balances solubility and orderly propulsion, promotes efficient charge transfer, and optimizes exciton utilization by adjusting molecular orientation and energy level matching, so that compared with the comparative example, the voltage is reduced and the life and efficiency are improved.

[0153] The above embodiment only lists the effect data of devices made with a part of the structural formula. This is a representative sampling test. According to the experimental data, the overall data is not much different and can represent the effects of other unlisted structures.

[0154] The applicant states that while the present invention uses the aforementioned embodiments to illustrate the organic electroluminescent materials and devices of the present invention, the present invention is not limited to these embodiments, nor does it necessarily rely on these embodiments for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. An organic electroluminescent doping material, characterized in that: The organic electroluminescent doping material has a structure shown in Formula I: X is one of N, O, S, Si, Ge, C or Se; R1-R8 are each independently selected from -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, substituted or unsubstituted C2-C24 alkyl, substituted or unsubstituted C3-C24 cycloalkyl, substituted or unsubstituted C6-C24 aryl and substituted or unsubstituted 4-24 membered heterocyclyl; R9-R 25 Each is independently selected from any one of -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, substituted or unsubstituted C2-C24 alkyl, substituted or unsubstituted C3-C24 cycloalkyl, substituted or unsubstituted C6-C24 aryl and substituted or unsubstituted 4-24 membered heterocyclyl; R1-R 25 Each of them exists independently or at least one of them forms a substituted or unsubstituted C3-C24 aliphatic ring, a substituted or unsubstituted C6-C24 aromatic ring, a substituted or unsubstituted C4-C24 aromatic heterocycle, or a substituted or unsubstituted C10-C24 condensed ring with other substituents on the ring; The substituents in the substituted group are selected from one or a combination of at least two of -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3; The heteroatom in the heterocyclic group is at least one of N, O or S; The hydrogen in formula I is not substituted by deuterium, partially substituted by deuterium, or completely substituted by deuterium; D stands for deuterium, T stands for tritium, and Me stands for methyl.

2. The organic electroluminescent doping material according to claim 1, characterized in that: X is selected from O or S.

3. The organic electroluminescent doping material according to claim 1, characterized in that: R1-R8 are each independently selected from any one or a combination of at least two of the following groups: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, tetrahydrofuran, thiolane, tetrahydropyran, phenyl, biphenyl , deuterated phenyl, dideuterated phenyl, terphenyl, naphthyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, triphenylene, pyrenyl, naphthacene, perylene, chrysene, fused tetraphenyl, fluoranthenyl, carbazolyl, furyl, thienyl, imidazolyl, thiazolyl, pyridyl, pyrimidinyl, benzofuranyl, benzothienyl, isobenzofuranyl, dibenzofuranyl, dibenzothienyl, benzimidazolyl, benzothiazolyl, quinolyl, isoquinolyl or the following substituents: Where * represents the attachment site of the group.

4. The organic electroluminescent doping material according to claim 1, characterized in that: R9-R 25 Each independently selected from any one or a combination of at least two of the following groups: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, tetrahydrofuran, thiolane, tetrahydropyran, Phenyl, biphenyl, deuterated phenyl, dideuterated phenyl, terphenyl, naphthyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, triphenylene, pyrenyl, naphthacene, perylene, chrysene, fused tetraphenyl, carbazolyl, fluoranthenyl, furanyl, thienyl, imidazolyl, pyrazolyl, thiazolyl, triazinyl, pyridyl, pyrazinyl, pyrimidinyl, benzofuranyl, benzothienyl, dibenzofuranyl, dibenzothienyl, benzodioxolyl, or the following substituents; Where * represents the attachment site of the group; R' is independently selected from any one or a combination of at least two of -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, biphenyl, deuterated phenyl, dideuterated phenyl, naphthyl, benzofuranyl, benzothiophenyl, furyl, thienyl, dibenzofuranyl or dibenzothiophenyl.

5. The organic electroluminescent doping material according to claim 1, characterized in that: R1-R 25 At least one of the substituents forms a cyclopentyl group, a cyclohexyl group, a benzene ring, a naphthalene ring, a benzofuranyl group, a benzothiophenyl group, a furyl group, a thiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group or a combination of at least two of the above groups with other substituents on the ring.

6. The organic electroluminescent doping material according to claim 1, characterized in that: The organic electroluminescent material is any one of the following compounds:

7. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises an anode, a cathode, and an organic material layer disposed between the anode and the cathode, wherein the organic material layer comprises at least one of the organic electroluminescent doping materials according to any one of claims 1 to 6.

8. The organic electroluminescent device according to claim 7, characterized in that: The organic material layer includes a light-emitting layer, and the light-emitting layer includes a host material and a doping material. The doping material includes at least one of the organic electroluminescent doping materials according to any one of claims 1 to 6.

9. The organic electroluminescent device according to claim 8, 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.

10. The organic electroluminescent device according to claim 9, characterized in that: The organic electroluminescent device comprises an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode which are arranged in sequence.

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