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

Abstract

The invention discloses an organic light-emitting doped material, a preparation method thereof and an organic electroluminescent device, and relates to the technical field of photoelectric devices. The structural formula of the organic light-emitting doped material is # imgabs0 #. According to the organic light-emitting doped material provided by the invention, the structures of different LA ligands are adjusted, some electrons, groups and the like are changed, the molecular space structure is changed, and the spin-orbit coupling effect of light-emitting molecules is improved, so that the organic light-emitting doped material is beneficial to generation of phosphorescence and enhancement of the quantum efficiency of the organic light-emitting doped material; an aromatic group compound is added while a trifluoromethyl group is introduced to dibenzofuran on an LB ligand, so that the compound disclosed by the invention can improve intermolecular symmetric dipole moment by adjusting the electrochemical characteristics of the compound, and meanwhile, the phosphorescence quantum efficiency and the electroluminescent efficiency of the material are improved; compared with a contrast, the organic electroluminescent device prepared by taking the compound as a luminescent layer doping material has the advantages that the driving voltage is obviously reduced, the luminous efficiency is obviously improved, and the service life is obviously prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic devices, and in particular, to an organic light-emitting doping material, a preparation method thereof, and an organic electroluminescent device. Background Art

[0002] OLED is short for Organic Light-Emitting Diode, also known as organic electroluminescent display and organic light-emitting semiconductor. OLED belongs to a current-type organic light-emitting device, and is a phenomenon of luminescence caused by the injection and recombination of carriers, and the luminescence intensity is proportional to the injected current. Under the action of an electric field, holes generated by the first electrode and electrons generated by the second electrode will move, and are respectively injected into the hole transport layer and the electron transport layer, and migrate to the light-emitting layer. When the two meet in the light-emitting layer, energy excitons are generated, thereby exciting the luminescent molecules to finally generate visible light.

[0003] The most important factor determining the luminous efficiency of an organic EL device is the luminescent material. So far, fluorescent materials have been widely used as luminescent materials. However, in view of the electroluminescence mechanism, the development of phosphorescent materials is one of the theoretically best methods, which can increase the luminous efficiency by up to four times compared with fluorescent substances. As a new generation of display technology, organic electroluminescent materials (OLEDs) have the advantages of ultra-thin, self-luminous, wide viewing angle, fast response, high luminous efficiency, good temperature adaptability, simple production process, low driving voltage, low energy consumption, etc., and have been widely used in industries such as flat panel displays, flexible displays, solid state lighting, and vehicle-mounted displays.

[0004] The light emitted by an organic electroluminescent device is also divided into fluorescence and phosphorescence. The light emitted by the energy of the singlet excitons is fluorescence, while the light emitted by the energy of both singlet and triplet excitons is phosphorescence. Because the ratio of the number of singlet and triplet states formed by excitons is a fixed value of 1:3, theoretically, the maximum internal quantum efficiency of a fluorescence device that only uses singlet excitons is only 25%, while on the contrary, the internal quantum efficiency when emitting phosphorescence can reach 100%.

[0005] However, in the prior art, when phosphorescent materials are applied to organic light-emitting devices, there are problems of 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.

[0006] In view of this, the present invention is specifically proposed. Summary of the Invention

[0007] The purpose of the present invention is to provide an organic light-emitting doping material, a preparation method thereof, and an organic electroluminescent device. The organic light-emitting doping material provided by the present invention adjusts different L AThe structure of the ligand is modified by changing some electrons and groups, etc., to alter the molecular spatial structure, improve the spin-orbit coupling effect of the luminescent molecule, making it conducive to the generation of phosphorescence and enhancing its quantum efficiency, while in L B While introducing a trifluoromethyl group onto the dibenzofuran of the ligand and then connecting an aromatic group, by enhancing the intermolecular conjugation degree, optimizing the energy level distribution of HOMO and LUMO, promoting charge separation and transport, regulating the electrochemical properties of the compound, improving the intermolecular symmetric dipole moment, and simultaneously improving the phosphorescent quantum efficiency and electroluminescent efficiency of the material. By changing the molecular spatial structure, regulating the electrochemical properties of the compound, and improving the chemical symmetry and dipole moment of the structure, the resulting organic compound, when used in an organic electroluminescent device, reduces the turn-on voltage of the device and improves the luminescence efficiency and lifespan of the device.

[0008] The present invention is implemented as follows: In a first aspect, the present invention provides an organic light-emitting doping material having a structure as shown in Formula I: Formula I; Wherein X is O; The R 1 -R 8 Are each independently selected from -H, -D, -T, -F, -CN, -CH 3 , -CD 3 , -CT 3 , -CF 3 , -CH 2 F, -CHF 2 , and any one of substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C6-C18 aryl, and substituted or unsubstituted 4- to 18-membered heterocyclic group; The Ar 1 Is a combination of -CF 3 And Groups, m is 2, wherein the Ar 4 Is independently selected from -F, -CH 3 , -CF 3 , -CH 2 F, -CHF 2 , -SiMe 3 , -GeMe 3 , and any one of substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C6-C18 aryl, and substituted or unsubstituted 4- to 18-membered heterocyclic group, and there can be no fusion between any two bonds of Ar 4 Or with any position of the ring where it is located, and q is an integer between 1 and 5; The Ar 2 is independently selected from -H, -D, -T, -F, -CN, -CH 3 , -CD 3 , -CT 3 , -CF 3 , -CH 2 F, -CHF 2 , -SiMe 3 , -GeMe 3 , any one of a substituted or unsubstituted C2-C18 alkyl group, a substituted or unsubstituted C6-C18 aryl group, and a substituted or unsubstituted 4-membered - 18-membered heterocyclic group, and n is an integer between 0 and 2; The Ar 3 is independently selected from -H, -D, -T, -F, -CN, -CH 3 , -CD 3 , -CT 3 , -CF 3 , -CH 2 F, -CHF 2 , -SiMe 3 , -GeMe 3 , a substituted or unsubstituted C2-C18 alkyl group, a substituted or unsubstituted C3-C18 cycloalkyl group, a substituted or unsubstituted C6-C18 aryl group, and p is an integer between 0 and 4.

[0009] In a second aspect, the present invention provides a method for preparing an organic light-emitting dopant material as described in any one of the foregoing embodiments, which includes the following steps: Reacting an intermediate L 1 with an R 8 -R A group in a system of ethylene glycol monoethyl ether and water with IrCl 3 •3H 2 O to fully react to form a bridged ligand of formula III; Reacting the bridged ligand of formula III with silver trifluoromethanesulfonate to form an intermediate of formula II with an R 1 -R 8 group; Reacting the intermediate of formula II with an R 1 -R 8 group with an intermediate L 1 with an Ar 3 -Ar B in an ethanol system to fully react to form the organic light-emitting dopant material; The synthetic route is as follows: .

[0010] In a third aspect, the present invention provides an organic electroluminescent device comprising the organic light-emitting dopant material as described in any one of the foregoing embodiments.

[0011] The present invention has the following beneficial effects: By adjusting the structures of different L A ligands, changing some electrons and groups, etc., and changing the molecular spatial structure, the spin-orbit coupling effect of the light-emitting molecules is improved, which is beneficial to the generation of phosphorescence and enhances its quantum efficiency. At the same time, while introducing a trifluoromethyl group on dibenzofuran of the L B ligand and adding an aromatic group compound, the compound of the present invention can improve the intermolecular symmetric dipole moment by adjusting the electrochemical properties of the compound, and at the same time improve the phosphorescence quantum efficiency and electroluminescence efficiency of the material. When the compound of the present invention is used as a dopant material for the light-emitting layer, the organic electroluminescent device prepared has a significantly lower driving voltage, and the luminous efficiency and lifespan are significantly improved compared with the organic electroluminescent device prepared in the comparative example. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0013] Figure 1 It is the NMR test spectrum of the compound of Structural Formula I-237. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Those reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase.

[0015] The present invention provides an organic light-emitting dopant material having the structure shown in Formula I: Formula I; X is O; R 1 -R 8 are each independently selected from -H, -D, -T, -F, -CN, -CH 3 , -CD 3 , -CT 3 , -CF 3 , -CH2 F, -CHF 2 , and any one of substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C6-C18 aryl, and substituted or unsubstituted 4- to 18-membered heterocyclic group; R 1 -R 8 The substitution in the substitution or non-substitution in 3 -D, -T, -F, -CN, -CH 3 -CD 3 -CT 3 -CF 2 F, -CHF 2 and -SiMe 3 is one or more of the following; Ar 1 is a combination of -CF 3 and groups, m is 2, where Ar 4 is independently selected from -F, -CH 3 , -CF 3 , -CH 2 F, -CHF 2 , -SiMe 3 , -GeMe 3 , and any one of substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C6-C18 aryl, and substituted or unsubstituted 4- to 18-membered heterocyclic group, and Ar 4 cannot be fused between any two bonds or to any position of the ring where it is located, q is an integer between 1 and 5; Ar 4 The substitution in the substitution or non-substitution in 3 -F, -CN, -CH 3 , -CF 2 , -CH 2 F, -CHF 3 , -SiMe 3 and -GeMe Ar 2 is independently selected from -H, -D, -T, -F, -CN, -CH 3 , -CD 3 , -CT 3 , -CF 3 , -CH 2 F, -CHF 2 , -SiMe 3 , -GeMe 3, any one of substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C6-C18 aryl, and substituted or unsubstituted 4- to 18-membered heterocyclic group, n is an integer between 0 and 2; Ar 2 The substitution in the substituted or unsubstituted means: -D, -T, -F, -CN, -CH 3 , -CD 3 , -CT 3 , -CF 3 , -CH 2 F, -CHF 2 and -SiMe 3 One or more of the following; Ar 3 Independently selected from -H, -D, -T, -F, -CN, -CH 3 , -CD 3 , -CT 3 , -CF 3 , -CH 2 F, -CHF 2 , -SiMe 3 , -GeMe 3 , substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C6-C18 aryl, p is an integer between 0 and 4; Ar 3 The substitution in the substituted or unsubstituted means: -D, -T, -F, -CN, -CH 3 , -CD 3 , -CT 3 , -CF 3 , -CH 2 F, -CHF 2 and -SiMe 3 One or more of the following;.

[0016] The above Ar 4 , Ar 2 and Ar 3 The heteroatoms in the heterocyclic group are independently selected from one or more of N, O, and S.

[0017] Compound I in the present invention has at least one of the following four specific structural formulas:

[0018] ; Wherein: R 1 -R 8 and Ar 1 , Ar 2 , Ar 3 , Ar 4As described above.

[0019] In some embodiments, R 1 -R 8 is independently selected from the following groups: -H, -D, -T, -F, -CN, -CH 3 , -CD 3 , -CT 3 , -CF 3 , -CH 2 F, -CHF 2 , methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, thiolane, phenyl, biphenyl, deuterated phenyl, di-deuterated phenyl, terphenyl, naphthyl, fluorenyl, phenanthryl, anthryl, indenyl, triphenylene, pyrenyl, tetraphenyl, perylenyl, chrysenyl, condensed tetraphenyl, fluoranthenyl, furyl, thienyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, benzofuryl, benzothienyl, isobenzofuryl, dibenzofuryl, dibenzothienyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, benzothiadiazolyl, quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenanthridinyl, and benzodioxolyl, or a combination of one or more of these groups; and / or, Ar 2 is selected from the following groups: -H, -D, -T, -F, -CN, -CH 3 , -CD 3 , -CT 3 , -CF 3 , -CH 2 F, -CHF 2 , -SiMe 3 , -GeMe 3、 methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, tetrahydrofuran, pyrrolidine, thiolane, tetrahydropyran, phenyl, biphenyl, deuterated phenyl, di-deuterated phenyl, terphenyl, naphthyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, triphenylenyl, pyrenyl, quaterphenyl, perylenyl, chrysenyl, condensed tetraphenyl, fluoranthenyl, furyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazanyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, benzofuranyl, benzothienyl, isobenzofuranyl, dibenzofuranyl, dibenzothienyl, benzimidazolyl, benzothiazolyl, benzoisothiazolyl, benzoisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, benzothiadiazolyl, quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenoxazinyl, phenanthridinyl, and benzodioxolyl, or a combination of one or more of these groups; and / or, Ar 3 selected from the following groups: -H, -D, -T, -F, -CN, -CH 3 -CD 3 -CT 3 -CF 3 -CH 2 F, -CHF 2 -SiMe 3 -GeMe 3 methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, biphenyl, deuterated phenyl, di-deuterated phenyl, terphenyl, naphthyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, pyrenyl, quaterphenyl, perylenyl, chrysenyl, condensed tetraphenyl, fluoranthenyl, or a combination of one or more of these groups; and / or, Ar 4 selected from the following groups: -F, -CN, -CH 3 -CF 3 -CH 2 F, -CHF 2 -SiMe 3 -GeMe 3 methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, thiolane, phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, triphenylenyl, pyrenyl, quaterphenyl, perylenyl, chrysenyl, condensed tetraphenyl, fluoranthenyl, furyl, thienyl, pyridyl, pyrimidinyl, benzofuranyl, benzothienyl, isobenzofuranyl, dibenzofuranyl, dibenzothienyl, or a combination of one or more of these groups.

[0020] Specifically, the organic light-emitting doping material of the present invention has at least one of the following specific structures shown by the following formula: 。

[0021] In addition, the present invention also provides a preparation method of the above-mentioned organic light-emitting doping material, which comprises the following steps: S1. React the intermediate L with the group R 1 -R 8 fully with IrCl A •3H 3 •3H 2 O in a system of ethylene glycol monoethyl ether and water to generate a bridged ligand of formula III; S2. React the bridged ligand of formula III with silver trifluoromethanesulfonate to generate an intermediate of formula II with the group R 1 -R 8 ; S3. React the intermediate of formula II with the group R 1 -R 8 fully with the intermediate L with Ar 1 -Ar 3 in an ethanol system to generate the above-mentioned organic light-emitting doping material; B The synthetic route thereof is as follows: The synthetic route thereof is as follows: 。

[0022] In addition, the present invention also provides an organic electroluminescent device, which comprises the above-mentioned organic light-emitting doping material. Specifically, the organic electroluminescent device comprises a first electrode, a hole transport region, a light-emitting layer, an electron transport region and a second electrode which are arranged in sequence, and the light-emitting layer is prepared from the above-mentioned organic light-emitting doping material.

[0023] A substrate can be used below 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, a thin film transistor (TFT) can also be provided on the substrate for display use.

[0024] The first electrode can be formed by sputtering or depositing a material used as the first electrode on a substrate. When the first electrode serves as the 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 that contribute to hole injection and their combinations other than the listed anode materials, including known materials suitable for making anodes. When the first electrode serves as the 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 that contributes to electron injection and its combination, including known materials suitable for making cathodes.

[0025] The hole transport region, the light-emitting layer, and the electron transport region together serve as the organic material layer, which is located between the first electrode and the second electrode. The organic material layer can be formed on the electrodes by methods such as vacuum thermal evaporation, spin coating, printing, etc. Compounds used as the organic material layer can be organic small molecules, organic macromolecules, and polymers, as well as their combinations. 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).

[0026] 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 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 as HT-1 to HT-34 below; or any combination thereof.

[0027] , but not limited to the above several materials.

[0028] 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-mentioned compounds HT-1 to HT-34, or one or more of the following compounds HI-1 - HI-3; it can also adopt one or more of the compounds HT-1 to HT-34 doped with one or more of the compounds HI-1 to HI-3: , but not limited to the above several materials.

[0029] The light-emitting layer can include light-emitting dyes (i.e., dopants) that can emit spectra of different wavelengths, and can also include a host material at the same time. The light-emitting layer can be a single-color light-emitting layer that emits a single color such as red, green, or blue. Multiple single-color light-emitting layers of different colors can be arranged in a planar pattern according to a pixel pattern, or stacked together to form a color light-emitting layer. When the light-emitting layers of different colors are stacked together, they can be separated from each other or connected to each other. The light-emitting layer can also be a single color light-emitting layer that can simultaneously emit different colors such as red and green.

[0030] According to different technologies, the light-emitting layer material can adopt different materials such as phosphorescent electroluminescent materials and thermally activated delayed fluorescence light-emitting materials. In an OLED device, a single light-emitting technology can be adopted, or a combination of multiple different light-emitting technologies can be adopted. These different light-emitting materials classified by technology can emit light of the same color or different colors.

[0031] The compound of formula I of the present invention is used as a doping material in the light-emitting layer.

[0032] The electron transport region can be a single-layer electron transport layer (ETL) structure, 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).

[0033] The electron transport layer material can be selected from, but not limited to, one or more combinations of the following listed ET-1 to ET-57.

[0034] 。

[0035] However, it is not limited to the above several materials.

[0036] 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: LiF, NaCl, CsF, Li 2 O, Cs 2 CO 3 , BaO, Na, Li, Ca.

[0037] The features and properties of the present invention will be further described in detail below in conjunction with the embodiments.

[0038] Compound Example 1 This compound example provides an organic light-emitting doping material I-237, that is, the compound numbered I-237. The specific synthesis steps are as follows: (1) L B -237 is not in the prior art and needs to be synthesized in a previous step. The synthesis steps of L B -237 are as follows:

[0039] Under a nitrogen protection system, 6-bromo-3-(trifluoromethyl)dibenz[b,d]furan (CAS: 2833655-79-9) (1.0 eq), bis(pinacolato)diboron (1.5 eq), X-Phos (0.12 eq), palladium acetate (0.02 eq), potassium acetate (3 eq) and dioxane are successively added to the reaction system. N 2 is displaced three times and N 2 is protected, and the mixture is heated and stirred at 100 °C overnight. After the reaction is completed, it is filtered through diatomaceous earth and anhydrous magnesium sulfate, washed twice with ethyl acetate, and the organic phase is collected and concentrated under reduced pressure to obtain the crude product intermediate formula L BⅢ -237, which is directly used for the next step.

[0040]

[0041] Under a nitrogen protection system, weigh compound 2-bromopyridine (CAS: 109-04-6) (1.0 eq), intermediate formula L BⅢ -237 (1.2 eq), anhydrous potassium carbonate (3.0 eq) into the reaction system, add toluene, absolute ethanol, purified water, and add Pd(PPh 3 ) 4 (0.02 eq) under nitrogen protection. After adding, reflux at 100 °C for 24 h under nitrogen protection, then cool to 25 °C. After the reaction is cooled, extract with ethyl acetate, wash three times with saturated brine, dry with anhydrous magnesium sulfate, concentrate under reduced pressure, and subject the crude product to column chromatography (200 - 300 mesh, 600 g) with the eluent EA:PE = 1:10 to remove impurities. Rotate the receiving solution until no liquid flows out, and dry it under vacuum to obtain the indicated compound intermediate L BⅡ -237 (yield 59%), with HPLC purity greater than 99.5%.

[0042] Mass spectrometry test value: 313.26.

[0043]

[0044] Under a nitrogen protection system, weigh compound intermediate L BⅡ -237 (1.0 eq), tetrahydrofuran. Start stirring under nitrogen protection, cool to -78 °C, dropwise add LDA (1.5 eq), keep stirring at this temperature for 2 h, add iodine (1.0 eq), and let it warm up to room temperature and react for 14 h. After the reaction is completed, separate the organic phase, extract, dry, perform column chromatography, and rotate to dry the solvent to obtain the indicated compound intermediate L BⅠ -237 (yield 68%), with HPLC purity greater than 99.5%.

[0045] Mass spectrometry test value: 439.26.

[0046]

[0047] Under a nitrogen protection system, weigh compound intermediate L BⅠ -237 (1.0 eq), 4-biphenylboronic acid (CAS: 5122-94-1) (1.1 eq), anhydrous potassium carbonate (3.0 eq) into the reaction system, add toluene, absolute ethanol, purified water, and add Pd(PPh 3 ) 4(0.02 eq), after addition, reflux at 100 °C for 24 h under nitrogen protection, then cool to 25 °C. After the reaction is cooled, extract with ethyl acetate, wash three times with saturated brine, dry with anhydrous magnesium sulfate, concentrate under reduced pressure, subject the crude product to column chromatography (200 - 300 mesh, 700 g), and use EA:PE = 1:13 as the eluent to remove impurities. Rotate the receiving solution until no liquid flows out, and dry under vacuum to obtain the shown compound intermediate L B -237 (yield 59%), with HPLC purity greater than 99.5%.

[0048] Mass spectrometry test value: 465.36.

[0049] (2) Synthesize I-237.

[0050]

[0051] Under a nitrogen protection system, weigh out the ligand L A -237 (5-methyl-2-phenylpyridine) (CAS: 3256-88-0) (2.5 eq), IrC1 3 ·3H 2 O (1.0 eq) into the reaction system, add a mixed solution of ethylene glycol monoethyl ether and pure water, reflux for 28 hours under nitrogen protection, then cool to room temperature. Precipitation occurs, filter the precipitate by suction, and wash and dry it successively with water, absolute ethanol, and petroleum ether. Obtain the shown bridged ligand III-237 (yield 59%).

[0052]

[0053] Weigh out the intermediate formula III-237 (1.0 eq), add silver trifluoromethanesulfonate (2.5 eq), then add dichloromethane to the system, add methanol, reflux for 26 hours under nitrogen protection, cool to room temperature, and concentrate the filtrate of column chromatography (short column) until a solid precipitates. Obtain the iridium complex intermediate formula II-237 (yield 90%).

[0054]

[0055] Weigh out the intermediate formula II-237 (1.0 eq), add the ligand formula L B -237 (2.5 eq), then add absolute ethanol to the system, reflux for 36 hours under nitrogen protection, filter by suction, wash with alcohol, and dry. Use dichloromethane as the solvent, perform silica gel column chromatography, and concentrate the filtrate until a solid precipitates to obtain the final shown compound formula I-237 (yield 29%).

[0056] Perform the following analytical tests on the organic light-emitting doping material I-237: HPLC purity: greater than 99.5%; The mass spectrometry test value is 993.49.

[0057] Elemental analysis: The calculated values are C, 65.31; H, 3.76; F, 5.74; N, 4.23; O, 1.61. The measured values are C, 65.33; H, 3.78; F, 5.73; N, 4.22; O, 1.64.

[0058] The 1H NMR spectrum of Compound I-237 is shown in the appendix Figure 1 .

[0059] The synthesis methods of other compounds are the same as those described above and will not be elaborated here one by one.

[0060] Device Example 1 Select Compound I-1 prepared by the present invention as the phosphorescent emitting material, with a doping concentration of 5%, and prepare an OLED device. The specific preparation method is as follows: (1) Ultrasonically treat the glass plate coated with the ITO transparent conductive layer in a commercial cleaning agent, rinse it in deionized water, ultrasonically degrease it in a mixed solvent of acetone:ethanol (volume ratio 1:1), bake it in a clean environment until all moisture is removed, clean it with ultraviolet light and ozone, and bombard the surface with a low-energy cation beam; (2) Place the glass substrate with the anode in a vacuum chamber, evacuate to 1×10 -5 ~9×10 -3 Pa, vacuum deposit HI-1 as the hole injection layer on the above anode layer film at a deposition rate of 0.1 nm / s and a total film thickness of 10 nm; then deposit the first hole layer HT-1 at a deposition rate of 0.1 nm / s and a thickness of 60 nm; then deposit the electron blocking layer EB-1 at a deposition rate of 0.1 nm / s and a film thickness of 5 nm; (3) Vacuum deposit EML as the light-emitting layer of the device on the hole transport layer. EML includes the host material GH-1 and the doping material I-1 of the present invention, with a doping mass percentage concentration of 5%, to form the organic light-emitting layer of the device. The deposition rate is 0.2 nm / s and the total film thickness is 30 nm; (4) Deposit a 1:1 mass ratio of ET-1:QLi as the electron transport material of the device's electron transport layer on the hole blocking layer at a deposition rate of 0.1 nm / s and a total film thickness of 30 nm; (5) Vacuum deposit a 1-nm-thick LiF as the electron injection layer and a 150-nm-thick Al layer as the cathode of the device on the electron transport layer in sequence. After encapsulation, an OLED device is obtained. Test the luminescence characteristics of the obtained device, and measure using a KEITHLEY 2400 source measurement unit and a CS-2000 spectroradiometer to evaluate the driving voltage, lifetime, and luminous efficiency.

[0061] The structures used are as follows:

[0062] Device Example 2 - 80 Referring to the method of Device Example 1 above, the only difference is that the doping material I - 1 is replaced with I - 2, I - 3, I - 15, I - 17, I - 18, I - 19, I - 31, I - 32, I - 33, I - 34, I - 35, I - 36, I - 80, I - 81, I - 93, I - 95, I - 96, I - 97, I - 109, I - 110, I - 111, I - 112, I - 113, I - 114, I - 158, I - 159, I - 171, I - 173, I - 174, I - 175, I - 187, I - 188, I - 189, I - 190, I - 191, I - 192, I - 197, I - 198, I - 210, I - 212, I - 213, I - 214, I - 226, I - 227, I - 228, I - 229, I - 230, I - 231, I - 236, I - 237, I - 249, I - 251, I - 252, I - 253, I - 265, I - 266, I - 267, I - 268, I - 269, I - 270, I - 328, I - 472, I - 473, I - 474, I - 478, I - 479, I - 480, I - 547, I - 548, I - 549, I - 550, I - 551, I - 552, I - 604, I - 606, I - 662, I - 663, I - 665, I - 666 respectively.

[0063] Device Comparative Example 1 - 36 An organic electroluminescent device was 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 structural compounds of Comparative Examples 1 - 36 respectively.

[0064]

[0065] The prepared organic electroluminescent devices were tested in the same way as in Example 1, and the results are shown in Table 1.

[0066] Experimental Example The driving voltage, luminous efficiency, and lifespan of the above device examples and device comparative examples of organic electroluminescent devices were characterized at a brightness of 8000 (nits), and the test results are shown in Table 1 below:

[0067] From the comparison between comparative compound 1-36 and the organic light-emitting doping material of the present invention, it can be seen that L B By introducing an additional trifluoromethyl group onto dibenzofuran in the ligand and simultaneously introducing an aromatic group onto the ring to which the trifluoromethyl group is attached, the electrochemical properties of the compound of the present invention are adjusted compared with the comparative compound, the intermolecular symmetric dipole moment is improved, and at the same time, the phosphorescence quantum efficiency and electroluminescence efficiency of the material are improved. When the compound of the present invention is used as a doping material for the light-emitting layer, the organic electroluminescent device prepared has a significantly lower driving voltage, and both the luminous efficiency and lifespan are improved compared with the organic electroluminescent device prepared in the comparative example.

[0068] From the comparison between comparative compound 1-36 and the organic light-emitting doping material of the present invention, it can be seen that by adjusting different L A The structure of the ligand, changing some electrons and groups, etc., changes the molecular spatial structure, improves the spin-orbit coupling effect of the light-emitting molecule, making it conducive to the generation of phosphorescence and enhancing its quantum efficiency. When the compound of the present invention is used as a doping material for the light-emitting layer, the organic electroluminescent device prepared has a significantly lower driving voltage, and both the luminous efficiency and lifespan are improved compared with the organic electroluminescent device prepared in the comparative example, and these data exceed any value attributable to experimental error.

[0069] Among them, when comparative compound 31 is compared with compound Ⅰ-1, Ⅰ-2, and Ⅰ-3 of the present invention's examples respectively, by changing the substituent combination on the dibenzofuran ring and replacing the deuterated benzene group with p-tolyl, p-tert-butylphenyl, and biphenyl respectively, the symmetric dipole moment of the material is improved, giving it better spatial torsion ability, making it more conducive to the generation of phosphorescence, and at the same time improving the intramolecular charge transfer effect and narrowing the energy level difference between the ground state and the excited state of the molecule. When the compound of the present invention is used as a doping material for the light-emitting layer, the organic electroluminescent device prepared has a significantly lower driving voltage, and both the luminous efficiency and lifespan are improved compared with the organic electroluminescent device prepared in the comparative example.

[0070] Among them, when comparative compound 12 and comparative compound 33 are compared with compound Ⅰ-80, Ⅰ-81 and Ⅰ-236, Ⅰ-237 of the present invention's examples respectively, L A The ligands are exactly the same, only changing L BIn the combined form of the ligand, after replacing D in the comparative compound with p-tert-butylbenzene and biphenyl respectively, it significantly enhances the conjugation degree of the molecule, simultaneously optimizes and regulates the energy level distribution of HOMO and LUMO, promotes charge separation and transport, so that compared with the organic electroluminescent device prepared in the comparative example, the driving voltage of the organic electroluminescent device prepared with the compound of the present invention as the doping material for the light-emitting layer is significantly reduced, and the luminous efficiency and lifespan are both improved.

[0071] The above embodiments only list the effect data of the devices made of a part of the structural formulas. This is a representative sampling test. Judging from the experimental data, the overall data do not differ much and can represent the effects of other unlisted structures.

[0072] The present invention adjusts different L A structures of the ligand, changes some electrons and groups, etc., changes the molecular spatial structure, improves the spin-orbit coupling effect of the light-emitting molecule, makes it conducive to the generation of phosphorescence, and enhances its quantum efficiency. At the same time, while introducing a trifluoromethyl group on dibenzofuran of the L B ligand and adding an aromatic group compound, compared with the comparative compound, the present invention compound adjusts the electrochemical characteristics of the compound, improves the intermolecular symmetric dipole moment, and simultaneously improves the phosphorescence quantum efficiency and electroluminescence efficiency of the material. So that compared with the organic electroluminescent device prepared in the comparative example, the driving voltage of the organic electroluminescent device prepared with the compound of the present invention as the doping material for the light-emitting layer is significantly reduced, and the luminous efficiency and lifespan are significantly improved.

[0073] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An organic light-emitting doping material, characterized in that: It has a structure as shown in Formula I: Formula I; The X is O; The R1-R8 are independently selected from any one of -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C6-C18 aryl and substituted or unsubstituted 4-18 membered heterocyclic group; Ar1 is -CF3 and A combination of groups, m is 2, wherein Ar4 is independently selected from any one of -F, -CH3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, a substituted or unsubstituted C2-C18 alkyl, a substituted or unsubstituted C3-C18 cycloalkyl, a substituted or unsubstituted C6-C18 aryl and a substituted or unsubstituted 4-membered to 18-membered heterocyclic group, and any two bonds of Ar4 or any position of the ring cannot be fused, and q is an integer between 1 and 5; The Ar2 is independently selected from any one of -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C6-C18 aryl and substituted or unsubstituted 4-18 membered heterocyclic group, and n is an integer between 0 and 2; The Ar3 is independently selected from -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, substituted or unsubstituted C2-C18 alkyl, substituted or unsubstituted C3-C18 cycloalkyl, substituted or unsubstituted C6-C18 aryl, and p is an integer between 0-4.

2. The organic light-emitting doping material according to claim 1, characterized in that: The substitution or non-substitution in the R1-R8, Ar2 and Ar3 refers to: one or more of -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2 and -SiMe3; And / or, the substitution in the substitution or non-substitution in Ar4 refers to: one or more of -F, -CN, -CH3, -CF3, -CH2F, -CHF2, -SiMe3 and -GeMe3; And / or, the heteroatoms in the heterocyclic groups in R1-R8, Ar4, Ar2 and Ar3 are independently selected from one or more of N, O and S.

3. The organic light-emitting doping material according to claim 1, characterized in that: The formula I has at least one of the following four specific structural formulas: ； Wherein: the R1-R8 and Ar1, Ar2, Ar3, Ar4 are consistent with the above.

4. The organic light-emitting doping material according to claim 1, characterized in that: The R1-R8 is selected from the following groups: -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, thiolane, phenyl, biphenyl, deuterated phenyl, deuterated phenyl, terphenyl, naphthyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, triphenylene, pyrene, tetraphenylene, perylene, chrysene, condensed tetraphenylene, fluoranthenyl, furanyl, thienyl, imidazolyl, pyrazole yl, thiazolyl, thiadiazolyl, isothiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, benzofuranyl, benzothiophenyl, isobenzofuranyl, dibenzofuranyl, dibenzothiophenyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenanthridinyl and benzodioxolyl; And / or, Ar2 is selected from 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, pyrrolidine, thiolane, tetrahydropyran, phenyl, biphenyl, deuterated phenyl, deuterated phenyl, terphenyl, naphthyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, triphenylene, pyrenyl, tetraphenylene, perylene, chrysene, condensed tetraphenyl, fluoranthenyl, furanyl, thienyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, thiadiazolyl, isothiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, triazinyl, tetrazinyl, triazolyl, tetrazolyl, furazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, benzofuranyl, benzothiophenyl, isobenzofuranyl, dibenzofuranyl, dibenzothiophenyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzisoxazolyl, benzoxazolyl, isoindolyl, indolyl, indazolyl, benzothiadiazolyl, quinolyl, isoquinolyl, cinnolinyl, quinazolinyl, quinoxalinyl, carbazolyl, phenoxazinyl, phenanthridinyl and benzodioxole; And / or, Ar3 is selected from 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, phenyl, biphenyl, deuterated phenyl, deuterated phenyl, terphenyl, naphthyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, pyrenyl, naphthyl, peryl, chrysene, tetraphenyl and fluoranthenyl, or a combination of multiple groups; And / or, Ar4 is selected from the following groups: -F, -CN, -CH3, -CF3, -CH2F, -CHF2, -SiMe3, -GeMe3, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, thiolane, phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthrenyl, anthracenyl, indenyl, triphenylene, pyrene, tetraphenyl, perylene, chrysene, fused tetraphenyl, fluoranthene, furanyl, thienyl, pyridyl, pyrimidinyl, benzofuranyl, benzothienyl, isobenzofuranyl, dibenzofuranyl and dibenzothienyl. One or a combination of multiple groups.

5. The organic light-emitting doping material according to claim 1, characterized in that: The organic light-emitting doping material has at least one of the specific structures shown in the following formula: 。 6. A method for preparing an organic light-emitting doping material according to any one of claims 1 to 5, characterized in that: It includes the following steps: The intermediate L with R1-R8 groups A The bridging ligand of formula III is fully reacted with IrCl3•3H2O in the system of ethylene glycol ether and water to generate the bridging ligand of formula III; the bridging ligand of formula III is then reacted with silver trifluoromethanesulfonate to generate the intermediate of formula II with R1-R8 groups; the intermediate of formula II with R1-R8 groups reacts with the intermediate of formula L with Ar1-Ar3 B Fully reacting in an ethanol system to generate the organic light-emitting doping material; Its synthetic route is as follows: 。 7. An organic electroluminescent device, characterized in that: It comprises the organic light-emitting doping material as described in any one of claims 1 to 5.

8. The organic electroluminescent device according to claim 7, characterized in that: It comprises a first electrode, a hole transport region, a light-emitting layer, an electron transport region and a second electrode which are arranged in sequence, and the light-emitting layer is prepared from the organic light-emitting doping material.

9. The organic electroluminescent device according to claim 8, characterized in that: The hole transport region includes at least one of a hole injection layer, a hole transport layer and an electron blocking layer.

10. The organic electroluminescent device according to claim 8, characterized in that: The electron transport region includes at least one of an electron injection layer, an electron transport layer and a hole blocking layer.

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