Divalent platinum complex, preparation method and application thereof, and organic photoelectric device

Abstract

The invention relates to the technical field of photoelectric materials and devices, and discloses a divalent platinum complex, a preparation method and application thereof and an organic photoelectric device. The divalent platinum complex has a structure as shown in a formula (I), wherein Ra, Rb and Rc are independently selected from monatomic substituent groups or polyatomic substituent groups; the monatomic substituent comprises hydrogen atoms and isotope atoms or halogen atoms thereof; the polyatomic substituent groups comprise alkyl, aryl, cycloalkyl, cycloalkenyl, heteroaryl, alkenyl, alkynyl, amino, hydroxyl, sulfydryl, nitryl, cyano, sulfinyl, sulfonyl, carboxyl, hydrazino, alkoxy, aryloxy, ester group, alkoxy carbonyl, amido, alkoxy carbonyl amino, aryloxy carbonyl amino, sulfamoyl, carbamoyl, alkylthio, ureido, phosphamido and silyl; a polymer group and one or more of the substituent groups containing isotope atoms; # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic materials and devices, and in particular to a divalent platinum complex, a preparation method and application thereof, and an organic optoelectronic device. Background Art

[0002] Organic Light-Emitting Diodes (OLEDs) materials can emit light of different colors when powered, and have great prospects in flat panel displays and solid-state lighting applications. Products related to molecular-level semiconductor technology represented by organic light-emitting diode (OLED) technology have many advantages in terms of applicability and low energy consumption. OLED luminescence technology has been commercialized in display and lighting. Based on the principle of the three primary colors of light, OLED as a light source needs to have the three primary colors of red, green and blue, or a broad spectrum of white light, in order to achieve white light illumination and full-color display applications.

[0003] White light is a combination of all visible light, and OLED white light devices can be used in lighting and display. However, compared with the monochromatic light device technology using monochromatic light emitting materials, white light devices generally use a combination of multiple light sources with different wavelengths, or use a stacked device with multiple light-emitting layers of different colors. White phosphorescent organic light-emitting diodes (WOLEDs) can be used in the next generation of lighting and display fields because of their surface emitting, flexibility, thinness, close to sunlight, low blue light, and no glare hazards. In terms of luminescence, yellow is a "combination" color. It is not one of the three primary colors of "RGB". It is a light color composed of equal amounts of red light and green light. Therefore, in color science, yellow phosphorescence is formed by filtering out blue light from white phosphorescence, and is often the complementary color auxiliary light color of blue light. Increasing yellow light can increase the brightness of mobile phones and TV screens and make the colors richer. Therefore, OLED TV displays will use light-emitting units that brighten and enhance colors in addition to the three primary colors of red, green, and blue. Moreover, the white light backplane technology currently used in large-size OLED display technology also uses a technology that mixes yellow light with other color light sources. In addition, the light that the human eye is most sensitive to is the greenish yellow light of about 555nm, which can be applied to the research and development of large-size OLED panels. It is necessary to add a yellow-green light color rendering unit on the basis of the red, green and blue primary color scheme to achieve the effect of brightening and coloring the TV display. The yellow-green phosphorescent material is compatible with the structure of the green light device, so the use of a high-efficiency, high-stability yellow-green phosphorescent device is the best solution for brightening and coloring the TV display. Therefore, the mutual cooperation of blue light and white phosphorescent light can be used to form a high-efficiency and high-stability white phosphorescent light source, and then the preparation of high-efficiency yellow phosphorescent luminescent materials and devices has practical application value in display and lighting. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem that OLED devices in the prior art lack luminescent materials that can emit stable and efficient yellow phosphorescence, and to provide a divalent platinum complex and a preparation method and application thereof, as well as an organic optoelectronic device; the present invention introduces 5-pyrazolpyridine into the ligand structure of the divalent platinum complex, wherein the pyrazole ring forms an N-Pt metal bond with the metal center through a nitrogen atom, thereby providing a yellow phosphorescent luminescent material with a wide spectrum.

[0005] In order to achieve the above object, the first aspect of the present invention provides a divalent platinum complex, wherein the divalent platinum complex has a structure shown in formula (I):

[0006]

[0007] Among them, R a , R b and R c The same or different, each independently present or absent, monosubstituted or polysubstituted, and R a , R b and R c Each is independently selected from a single atomic substituent or a polyatomic substituent; the single atomic substituent includes a hydrogen atom and its isotope atoms or a halogen atom; the polyatomic substituent includes a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group, a cycloalkenyl group, a heteroaryl group, an alkenyl group, an alkynyl group, an amino group, a hydroxyl group, a thiol group, a nitro group, a cyano group, a sulfinyl group, a sulfonyl group, a carboxyl group, a hydrazine group, an alkoxy group, an aryloxy group, an ester group, an alkoxycarbonyl group, an amide group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, a urea group, a phosphoramide group, a silyl group, a polymer group and one or more of the above substituents containing isotope atoms.

[0008] The second aspect of the present invention provides a method for preparing a divalent platinum complex, wherein the preparation method comprises:

[0009] (1) performing a fragment coupling reaction of a first ligand represented by formula (a) and 9-(pyridin-2-yl)-9H-carbazole-2-ol represented by formula (b) to obtain a second ligand represented by formula (c);

[0010]

[0011] (2) in the presence of a platinum salt, subjecting the second ligand represented by formula (c) to a metal coordination cyclization reaction to obtain a divalent platinum complex represented by formula (I);

[0012]

[0013] Among them, R in formula (a), formula (b) and formula (I)a , R b and R c Same definition as above.

[0014] The third aspect of the present invention provides a divalent platinum complex prepared by the aforementioned preparation method.

[0015] A fourth aspect of the present invention provides a use of the aforementioned divalent platinum complex in an electroluminescent material and / or a photoluminescent material.

[0016] A fifth aspect of the present invention provides a use of the aforementioned divalent platinum complex in organic optoelectronic devices for lighting and / or display.

[0017] A sixth aspect of the present invention provides an organic optoelectronic device, wherein the organic optoelectronic device comprises a light-emitting layer, and the light-emitting layer comprises the aforementioned divalent platinum complex.

[0018] Through the above technical scheme, the divalent platinum complex provided by the present invention has the chemical structure described in formula (I), and is a yellow phosphorescent luminescent material. The present invention introduces 5-pyrazolylpyridine into the ligand structure of the divalent platinum complex, and the structure has a suitable triplet energy, a more stable carbon-platinum coordination bond and a more stable excited-state conjugated system compared to the nitrogen-platinum coordination bond, and the obtained tetradentate ligand-coordinated platinum heterocomplex has a yellow phosphorescent luminescence peak between 539-556nm. This series of phosphorescent platinum complexes can be used to develop white light monochromatic devices, and can also be used for tri-primary white light devices, and applied to lighting or display products. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a luminescence spectrum diagram of complex 1 in a specific embodiment of the present invention in solution and film;

[0020] Figure 2 It is the emission and excitation spectrum diagram of the complex 1 at low temperature in the specific embodiment of the present invention;

[0021] Figure 3 is a luminescence spectrum diagram of different concentrations in a film of complex 1 in a specific embodiment of the present invention;

[0022] Figure 4 is the UV-visible absorption spectrum of complex 13 in a specific embodiment of the present invention;

[0023] Figure 5 is the complex 1 in the specific embodiment of the present invention 1 H NMR spectrum;

[0024] Figure 6 is a mass spectrum of complex 1 in a specific embodiment of the present invention;

[0025] Figure 7 Yellow phosphor device structure diagram;

[0026] Figure 8 is the luminescence spectrum of the yellow phosphorescent device using complex 1 in a specific embodiment of the present invention;

[0027] Fig. 9 The luminescence spectrum of the white phosphorescent device prepared using complex 1 is shown;

[0028] Fig.10 is a power efficiency diagram of a yellow phosphorescent device using complex 1 in a specific embodiment of the present invention;

[0029] Fig.11 is a current efficiency diagram of a yellow phosphorescent device using complex 1 in a specific embodiment of the present invention;

[0030] Fig.12 Graph showing the external quantum efficiency of a yellow phosphorescent device using complex 1 in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0031] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0032] As mentioned above, the first aspect of the present invention provides a divalent platinum complex, wherein the divalent platinum complex has a structure shown in formula (I):

[0033]

[0034] Among them, R a , R b and R c The same or different, each independently present or absent, monosubstituted or polysubstituted, and R a , R b and R cEach is independently selected from a single atomic substituent or a polyatomic substituent; the single atomic substituent includes a hydrogen atom and its isotope atoms or a halogen atom; the polyatomic substituent includes a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group, a cycloalkenyl group, a heteroaryl group, an alkenyl group, an alkynyl group, an amino group, a hydroxyl group, a thiol group, a nitro group, a cyano group, a sulfinyl group, a sulfonyl group, a carboxyl group, a hydrazine group, an alkoxy group, an aryloxy group, an ester group, an alkoxycarbonyl group, an amide group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, a urea group, a phosphoramide group, a silyl group, a polymer group and one or more of the above substituents containing isotope atoms.

[0035] The inventors of the present invention have found that by introducing 5-pyrazolopyridine into the ligand of the divalent platinum complex, wherein the pyrazole ring forms an N-Pt metal bond with the metal center through a nitrogen atom, a wide-spectrum yellow phosphorescent luminescent material is provided. In an embodiment of the present invention, the disclosed divalent platinum complex molecule coordinated by a neutral tetradentate ligand containing a 5-pyrazolopyridine structure can emit yellow phosphorescence as a phosphorescent luminescent material, and has good stability, high efficiency and is within the range of long-wavelength yellow phosphorescence, and is completely suitable as an organic yellow phosphorescent luminescent body in OLED-related products. In addition, the compounds provided by the embodiments of the present invention are easy to prepare and sublimate and purify, are soluble in general organic solvents, and can be suitable for device processes processed by evaporation and solution methods at the same time. The luminescent properties of this type of material have the characteristics of low energy and good color purity, which comprehensively surpasses various fluorescent materials in the prior art, and at the same time achieves the effect of emitting yellow phosphorescent light and improving device performance; the stable complex luminescent materials provided by the embodiments of the present invention have CIE coordinates and luminous efficiency that are more in line with the needs of flat panel displays. At the same time, this series of yellow phosphorescent materials can be used as auxiliary light color materials for blue light to form a high-efficiency, high-stability white phosphorescent light source, and has great development potential in the fields of display and lighting.

[0036] According to the present invention, the substituted alkyl group is selected from one or more of an aryl-substituted alkyl group, a fluorine-substituted alkyl group and a halogenated alkyl group.

[0037] According to the present invention, the substituted aryl group is selected from an alkyl-substituted aryl group and / or an aryl-substituted aryl group.

[0038] According to the present invention, the amino group includes one or more of a monoalkylamino group, a dialkylamino group, a monoarylamino group and a diarylamino group.

[0039] According to the present invention, the cyano group is an isocyano group.

[0040] According to the present invention, R a , R b and R cEach is independently selected from deuterium, -CDH2, -CD2H, -CD3, -CDR1R2, -CD2R1, wherein R1 and R2 are each independently selected from one or more of substituted or unsubstituted alkyl, substituted or unsubstituted aryl, alkyl-substituted aryl, aryl-substituted aryl, cycloalkyl, cycloalkenyl, heteroaryl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, ester, alkoxycarbonyl, amide, alkoxycarbonylamino, aryloxycarbonylamino, sulfamoyl, carbamoyl, alkylthio, urea, phosphoramide, silyl and polymer groups.

[0041] According to the present invention, R b One or more selected from alkyl, aryl-substituted alkyl, aryl, alkyl-substituted aryl, aryl-substituted aryl, cycloalkyl, cycloalkenyl, heteroaryl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, halogenated alkyl, ester, alkoxycarbonyl, amide, alkoxycarbonylamino, aryloxycarbonylamino, sulfamoyl, carbamoyl, alkylthio, urea, phosphoramido, silyl and polymer groups.

[0042] According to the present invention, the alkyl group is C1-C 30 The alkyl group is preferably C1-C 24 of alkyl.

[0043] According to the present invention, the isotope atoms are deuterium atoms and / or tritium atoms.

[0044] According to the present invention, the halogen atom is selected from one or more of a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0045] According to the present invention, R a , R b and R ceach independently selected from the group consisting of methyl, deuterated methyl, benzyl, diphenylmethyl, triphenylmethyl, ethyl, 2-phenylethyl, 2,2-phenylethyl, 2,2,2-trifluoroethyl, propyl, isopropyl, 3,3,3-trifluoropropyl, 1,1,1,3,3,3-hexafluoro-2-propyl, butyl, isobutyl, hexafluoroisobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, phenyl, 2-methylphenyl, 2-isopropylphenyl, 2-ethylphenyl, 4-methylphenyl, phenyl, 4-isopropylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 2,3-dimethylphenyl, 2,3-diethylphenyl, 2,3-diisopropylphenyl, 2,3-diisobutylphenyl, 2,3-dicyclohexylphenyl, 2,3-dicyclopropylphenyl, 2,3-dicyclobutylphenyl, 2,3-dicyclopentylphenyl, 2,4-dimethylphenyl, 2,4-diethylphenyl, 2,4-diisopropylphenyl, 2,4-diisobutylphenyl, 2,4-dicyclohexylphenyl , 2,4-dicyclopropylphenyl, 2,4-dicyclobutylphenyl, 2,4-dicyclopentylphenyl, 2,6-dimethylphenyl, 2,6-diethylphenyl, 2,6-diisopropylphenyl, 2,6-diisobutylphenyl, 2,6-dicyclohexylphenyl, 2,6-dicyclopropylphenyl, 2,6-dicyclobutylphenyl, 2,6-dicyclopentylphenyl, 3,5-dimethylphenyl, 3,5-diethylphenyl, 3,5-diisopropylphenyl, 3,5-diisobutylphenyl, 3, One or more of 5-dicyclohexylphenyl, 3,5-dicyclopropylphenyl, 3,5-dicyclobutylphenyl, 3,5-dicyclopentylphenyl, 2,3,5,6-tetramethylphenyl, 2,4,6-trimethylphenyl, 2,4,6-triethylphenyl, 2,4,6-triisopropylphenyl, 2,4,6-triisobutylphenyl, 2,4,6-tricyclohexylphenyl, 2,4,6-tricyclopropylphenyl, 2,4,6-tricyclobutylphenyl and 2,4,6-tricyclopentylphenyl.

[0046] According to the present invention, in some specific embodiments of the present invention, R a is a hydrogen atom and / or a 2,4,6-trimethylphenyl group; R b One or more selected from isopropyl, 2,4,6-trimethylphenyl and 2,6-diisopropylphenyl.

[0047] According to the present invention, the divalent platinum complex is selected from at least one of the complexes 1-30 shown below:

[0048]

[0049]

[0050]

[0051] The second aspect of the present invention provides a method for preparing a divalent platinum complex, wherein the preparation method comprises:

[0052] (1) performing a fragment coupling reaction of a first ligand represented by formula (a) and 9-(pyridin-2-yl)-9H-carbazole-2-ol represented by formula (b) to obtain a second ligand represented by formula (c);

[0053]

[0054] (2) in the presence of a platinum salt, subjecting the second ligand represented by formula (c) to a metal coordination cyclization reaction to obtain a divalent platinum complex represented by formula (I);

[0055]

[0056] Among them, R in formula (a), formula (c) and formula (I) a , R b and R c Same definition as above.

[0057] According to the present invention, the coupling reaction of the fragments further comprises carrying out the reaction in the presence of cuprous bromide, 2,2,6,6-4-methyl-3,5-heptanedione, potassium hydroxide and N-methylpyrrolidone.

[0058] According to the present invention, relative to 0.5-5 mL of N-methylpyrrolidone, the molar number of the ligand (3-pyrazolopyridine) represented by formula (a) is 0.05-10 mmol, the molar number of the 9-(pyridin-2-yl)-9H-carbazole-2-ol represented by formula (b) is 0.15-15 mmol, the molar number of cuprous bromide is 0.05-5 mmol, the molar number of 2,2,6,6-4-methyl-3,5-heptanedione is 0.05-5 mmol, and the molar number of potassium hydroxide is 0.1-10 mmol.

[0059] According to the present invention, the conditions for the coupling reaction of the fragments include: stirring for 24-72 hours at a temperature of 80-250° C. under a N2 atmosphere.

[0060] According to the present invention, the metal coordination cyclization reaction further comprises carrying out the reaction in the presence of acetic acid.

[0061] According to the present invention, the platinum salt is potassium chloroplatinite.

[0062] And / or, relative to 5-100 mL of acetic acid, the molar amount of the second ligand represented by formula (c) is 0.01-10 mmol, and the molar amount of potassium chloroplatinite is 0.01-10 mmol.

[0063] According to the present invention, the conditions of the metal coordination cyclization reaction include: in a N2 atmosphere, first stirring at a temperature of 20-60°C for 12-48 hours; then heating to 100-180°C and stirring for 12-60 hours.

[0064] According to the present invention, preferably, the provided complex can be synthesized by the following general route, the specific steps of which are the coupling reaction of the fragments and the metal coordination cyclization reaction:

[0065] 1) Fragment coupling reaction:

[0066]

[0067] 2) Metal coordination cyclization reaction:

[0068]

[0069] Among them, R a , R b and R c The definition of is the same as in formula (I).

[0070] The third aspect of the present invention provides a divalent platinum complex prepared by the aforementioned preparation method.

[0071] A fourth aspect of the present invention provides a use of the aforementioned divalent platinum complex in an electroluminescent material and / or a photoluminescent material.

[0072] According to the present invention, the divalent platinum complex is used as a yellow phosphorescent luminescent material and / or a phosphorescent luminescent material.

[0073] A fifth aspect of the present invention provides a use of the aforementioned divalent platinum complex in organic optoelectronic devices for lighting and / or display.

[0074] A sixth aspect of the present invention provides an organic optoelectronic device, wherein the organic optoelectronic device comprises a light-emitting layer, and the light-emitting layer comprises the aforementioned divalent platinum complex.

[0075] According to the present invention, the organic photoelectric device further comprises a substrate, an anode layer, a hole transport layer, an electron transport layer and a metal cathode layer, wherein the electron transport layer and / or the hole transport layer comprises the aforementioned divalent platinum complex.

[0076] According to the present invention, the divalent platinum complex is the luminescent material, host material or guest material in the luminescent layer.

[0077] The present invention will be described in detail below through examples.

[0078] In the following examples and comparative examples:

[0079] (1) Nuclear magnetic resonance spectroscopy analysis: in CDCl3 or DMSO-d6 solution, recorded by Varian liquid nuclear magnetic resonance instrument 1 HNMR (hydrogen nuclear magnetic resonance) and 13 C NMR spectra were recorded at 300 MHz, 400 MHz or 500 MHz, and chemical shifts were based on residual protonated solvent. If CDCl3 was used as solvent, tetramethylsilane (δ = 0.00 ppm) was used as an internal reference. 1 H NMR (hydrogen nuclear magnetic resonance) spectrum; recorded using CDCl3 (δ = 77.00 ppm) as an internal reference 13 C NMR (carbon nuclear magnetic resonance) spectrum. If DMSO-d6 is used as solvent, residual H2O (δ=3.33 ppm) is used as an internal reference to record 1 H NMR (hydrogen nuclear magnetic resonance) spectrum; recorded using DMSO-d6 (δ = 39.52 ppm) as an internal reference 13 C NMR (carbon nuclear magnetic resonance) spectroscopy. The following abbreviations are used to explain 1 H NMR (hydrogen nuclear magnetic resonance) multiplicity: s = singlet, d = doublet, t = triplet, q = quadruplet, p = quintet, m = multitet, br = broad.

[0080] (2) Mass spectrometry analysis: Some compounds were tested by electrospray ionization mass spectrometry (ESI-MS) using a Waters Aquity Qda ultrahigh pressure liquid chromatography-mass spectrometry instrument, or by high-resolution mass spectrometry using a matrix-assisted ionization time-of-flight mass spectrometer (MALDI-TOF-MS).

[0081] (3) Material purification: The final product, the platinum complex, was separated by column chromatography and preparative HPLC, and then purified by ultra-high vacuum (10 -4 ~10 -5 Pa) sublimation purification equipment is used to perform sublimation purification to the purity requirement for device production.

[0082] (4) High performance liquid chromatography analysis: using methanol / water (1 / 9) as the mobile phase, the purity of the platinum complex sample was analyzed.

[0083] (5) Cyclic voltammetry curve test and energy level calculation: The test uses a three-electrode system, with a platinum column as the working electrode, a platinum wire as the counter electrode, and silver / silver chloride (Ag / AgCl) as the reference electrode. Under a nitrogen atmosphere, the sample was tested using N,N-dimethylformamide containing 0.1M tetrabutylammonium hexafluorophosphate as the solvent, ferrocene as the internal standard, and a scan rate of 100mV / s. According to formulas 5-1, 5-2 and the CV test results, the highest occupied orbital (HOMO) and lowest unoccupied orbital (LUMO) energy levels of the platinum complex molecule can be calculated. Since the measured potential of ferrocene relative to the reference electrode in DMF solution is not a fixed value, but has slight differences in different platinum complex solutions, we choose the ferrocene redox potential measured in the test for calculation.

[0084] HOMO=-[E ox -E Fc / Fc+ox +4.8]eV 5-1

[0085] LUMO=-[E red -E Fc / Fc+red +4.8]eV 5-2

[0086] Where: E ox 、E red are the oxidation peak onset potential and reduction peak onset potential of the sample, E Fc / Fc+ox 、E Fc / Fc+red are the onset potential of the oxidation peak and the reduction peak of ferrocene, respectively, and 4.8 is the vacuum energy level of ferrocene.

[0087] (6) UV-Vis absorption spectrum test: The absorption spectrum of the platinum complex in dichloromethane solution at room temperature was tested with a scanning range of 250 to 500 nm and an interval of 1 nm.

[0088] (7) Steady-state spectrum test: The room temperature dichloromethane solution spectrum of the platinum complex, the 77K 2-methyltetrahydrofuran luminescence spectrum / excitation spectrum, and the 5wt% doped polymethyl methacrylate (PMMA) film spectrum were tested. The dichloromethane solution spectrum was tested after the solvent was fully bubbling with nitrogen; the polymer doped film was prepared by spin coating in a glove box using chloroform as the solvent and a quartz sheet as the film carrier; the film sample was tested in a glove box or a vacuum chamber to reduce the quenching effect of oxygen on the luminescence of the complex. In addition, the photoluminescence quantum yield (PLQY) of the platinum complex solution and film was tested using an integrating sphere.

[0089] (8) Transient spectrum and phosphorescence lifetime test: The room temperature dichloromethane solution of the platinum complex was subjected to time-resolved spectrum test and luminescence lifetime half-life test using the Fluorolog-3 full spectrum optical platform. The lifetime test was performed on the 5wt% doped PMMA film. All tests were performed under nitrogen or vacuum conditions.

[0090] Example 1

[0091] Preparation of complex 1.

[0092] (1) Synthesis of 6-methyl-N,N-diphenyl-3-(1H-pyrazol-1-yl)-5-((9-(pyridin-2-yl)-9H-carbazole-2-yl)oxy)pyridin-2-amine:

[0093]

[0094] 5-Bromo-6-methyl-N,N-diphenyl-3-(1H-pyrazol-1-yl)pyridin-2-amine (203 mg, 0.5 mmol), 9-(pyridin-2-yl)-9H-carbazole-2-ol (240 mg, 0.75 mmol), cuprous bromide (44 mg, 0.25 mmol), 2,2,6,6-4-methyl-3,5-heptanedione (92 mg, 0.5 mmol), potassium hydroxide (56 mg, 1 mmol) and N-methylpyrrolidone (NMP) (1.5 mL) were added to a 30 mL sealed tube. The reaction was heated to 180 ° C under N2 atmosphere and stirred for 24 h. After the system was cooled, water was added to quench, and the organic phase was extracted with DCM. The organic phases were combined and dried, and the crude product was obtained by spin drying. The crude product was separated to obtain a white solid with a yield of 30%.

[0095] 6-methyl-N,N-diphenyl-3-(1H-pyrazol-1-yl)-5-((9-(pyridin-2-yl)-9H-carbazol-2-yl)oxy)pyridin-2-amine 1 H NMR spectrum: 1H NMR(400MHz,DMSO-d6)δ8.70(d,J=4.8Hz,1H),8.19(d,J=8Hz,1H),8.15-8.02(m,3H) ,7.89(t,J=1.6Hz,1H),7.77(d,J=8.0Hz,2H),7.59(d,J=8.4Hz,2H),7.47(d,J=5.3Hz ,1H),7.45-7.40(m,1H),7.34(d,J=7.6Hz,1H),7.27(dd,J=16.2,7.6Hz,8H),6.98(s, 1H), 6.94 (d, J = 8.3Hz, 1H), 6.72 (t, J = 1.6Hz, 1H), 6.53 (d, J = 8.6Hz, 1H), 2.33 (s, 3H).

[0096] (2) Synthesis of complex 1:

[0097]

[0098] Add 6-methyl-N,N-diphenyl-3-(1H-pyrazol-1-yl)-5-((9-(pyridin-2-yl)-9H-carbazole-2-yl)oxy)pyridin-2-amine (56.5 mg, 0.1 mmol), potassium chloroplatinate (K2PtCl4) (66 mg, 0.11 mmol) and acetic acid (HOAc) (10 mL) to a 38 mL sealed tube. The reaction was heated to 30 ° C under N2 atmosphere, stirred for 24 h, and then continued to heat to 120 ° C and stirred for 48 h. After the reaction was completed, the system was cooled to room temperature, water was added to quench, the organic phase was extracted with DCM, the obtained organic phases were combined and dried, and the crude product was obtained by spin drying. The crude product was separated to obtain a yellow solid with a yield of 25.4%.

[0099] Complex 1 1 H NMR spectrum: 1 H NMR (400MHz, DMSO-d6) δ8.69 (dd, J=4.9, 1.9Hz, 1H), 8.02 (d, J=7.6Hz, 1H), 7.95-7.89 ( m,1H),7.87(s,1H),7.83(d,J=2Hz,1H),7.77(d,J=8.8Hz,2H),7.66(dd,J=8.6,1.0Hz, 2H),7.58(d,J=8.1Hz,1H),7.40(m,1.3H),7.33(m,4H),7.28(m,3H),7.17(d,J=1.6Hz, 1H), 6.98 (t, J = 7.4Hz, 1H), 6.73 (s, 1H), 6.52 (d, J = 2Hz, 1H), 6.41 (m, 1H), 2.46 (s, 3H).

[0100] Example 2

[0101] Preparation of complex 13.

[0102] (1) Synthesis of N,N,6-triphenyl-3-(1H-pyrazol-1-yl)-5-((9-(pyridin-2-yl)-9H-carbazole-2-yl)oxy)pyridin-2-amine:

[0103]

[0104] 5-Bromo-N,N,6-triphenyl-3-(1H-pyrazol-1-yl)pyridin-2-amine (233 mg, 0.5 mmol), 9-(pyridin-2-yl)-9H-carbazole-2-ol (240 mg, 0.75 mmol), cuprous bromide (44 mg, 0.25 mmol), 2,2,6,6-4-methyl-3,5-heptanedione (92 mg, 0.5 mmol), potassium hydroxide (56 mg, 1 mmol) and N-methylpyrrolidone (1.5 mL) were added to a 30 mL sealed tube. The reaction was heated to 180 ° C under N2 atmosphere and stirred for 24 h. After the system was cooled, water was added to quench, and the organic phase was extracted with DCM. The organic phases were combined and dried, and the crude product was obtained by spin drying. The crude product was separated to obtain a white solid with a yield of 27%. MS (ESI) 647.75 [M+1] + .

[0105] (2) Synthesis of complex 13:

[0106]

[0107] Add N,N,6-triphenyl-3-(1H-pyrazol-1-yl)-5-((9-(pyridin-2-yl)-9H-carbazole-2-yl)oxy)pyridin-2-amine (64.6 mg, 0.1 mmol), potassium chloroplatinate (66 mg, 0.11 mmol) and acetic acid (10 mL) to a 38 mL sealed tube. The reaction was heated to 30 ° C under N2 atmosphere, stirred for 24 h, and then continued to heat to 120 ° C and stirred for 48 h. After the reaction was completed, the system was cooled to room temperature, quenched with water, and the organic phase was extracted with DCM. The obtained organic phases were combined and dried, and the crude product was obtained by spin drying. The crude product was separated to obtain a yellow solid with a yield of 22.8%. MS (ESI) 840.32 [M + 1] + .

[0108] Example 3

[0109] Preparation of complex 25.

[0110] (1) Synthesis of 6-(2,6-diisopropylphenyl)-3-(4-methyltrialkyl-1H-pyrazol-1-yl)-N,N-diphenyl-5-((9-(pyridin-2-yl)-9H-carbazole-2-alkyl)oxy)pyridin-2-amine:

[0111]

[0112] 5-Bromo-6-(2,6-diisopropylphenyl)-3-(4-methyltriacyl-1H-pyrazol-1-yl)-N,N-diphenylpyridine-2-amine (335 mg, 0.5 mmol), 9-(pyridin-2-yl)-9H-carbazole-2-ol (240 mg, 0.75 mmol), cuprous bromide (44 mg, 0.25 mmol), 2,2,6,6-4-methyl-3,5-heptanedione (92 mg, 0.5 mmol), potassium hydroxide (56 mg, 1 mmol) and N-methylpyrrolidone (1.5 mL) were added to a 30 mL sealed tube. The reaction was heated to 180 ° C under N2 atmosphere and stirred for 24 h. After the system was cooled, water was added to quench, and the organic phase was extracted with DCM. The organic phases were combined and dried, and the crude product was obtained by spin drying. The crude product was separated to obtain a white solid with a yield of 19%. MS(ESI)850.10[M+1] + .

[0113] (2) Synthesis of complex 25:

[0114]

[0115] Add 6-(2,6-diisopropylphenyl)-3-(4-methyltrialkyl-1H-pyrazol-1-yl)-N,N-diphenyl-5-((9-(pyridin-2-yl)-9H-carbazole-2-alkyl)oxy)pyridine-2-amine (85 mg, 0.1 mmol), potassium chloroplatinate (66 mg, 0.11 mmol) and acetic acid (10 mL) to a 38 mL sealed tube. The reaction was heated to 30 ° C under N2 atmosphere, stirred for 24 h, and then continued to heat to 120 ° C and stirred for 48 h. After the reaction was completed, the system was cooled to room temperature, water was added to quench, the organic phase was extracted with DCM, the obtained organic phases were combined and dried, and the crude product was obtained by spin drying. The crude product was separated to obtain a yellow solid with a yield of 16%. MS (ESI) 1043.32 [M+1] + .

[0116] Comparative Example 1

[0117] According to the reference: "Tetradentate Pt(II) Complexes for Spectrum-Stable Deep-Blue and White Electroluminescence", Lu Zhu, Wentao Xie, Chunyue Qian, Wang Xie, Kang Shen, Anqi Lv, Huili Ma, Hongbo Li, Xiao-Chun Hang, Wenqi Li, Shi-Jian Su, and Wei Huang*Adv.Optical Mater.2020,2000406; wherein, the Pt(II) complex has the following structural formula (4-pyrazolopyridine), and the Pt(II) complex emits blue light.

[0118]

[0119] Test Example 1

[0120] Characterization of luminescence properties of compounds

[0121] This test example is to illustrate the application of the divalent platinum complex prepared in the above example as an electroluminescent material or a photoluminescent material.

[0122] Optionally, the divalent platinum complex is a yellow phosphorescent material or a phosphorescent material. The yellow phosphorescent wavelength peak of the divalent platinum complex prepared in the embodiment of the present invention is in the range of 539-556 nm.

[0123] Representative data on the color purity of the emitter can be obtained from the emission spectra of films prepared using 5% doping of the complex material in polymethyl methacrylate (PMMA). Table 1 shows the emission spectrum data of the complex.

[0124] Table 1

[0125]

[0126] In the above Table 1, λ is the peak wavelength, and CIE (x, y) is the chromaticity coordinate parameter according to the International Commission on Illumination standard. The peak wavelengths of the complexes 1, 13, and 25 prepared in the embodiments of the present invention are between 539-556 nm, their half-peak widths are all above 80 nm, and the photoluminescence efficiency is above 80%; while the peak wavelength of the comparative example 1 is between 451 nm, its half-peak width is 43 nm, and the phosphorescence quantum efficiency is 73%, indicating that the divalent platinum complex having the structure of formula (I) is a high-efficiency wide-spectrum yellow phosphorescent luminescent material.

[0127] Figure 1The luminescence spectra of divalent platinum complex 1 in solution and film under 400nm ultraviolet light excitation are shown; the luminescence wavelength peak in polymethyl methacrylate (PMMA) film is 509nm, and its main luminescence range is green light, yellow light and a small amount of orange-red light, which comprehensively shows a yellow light luminescence effect. This shows that this series of complexes are very good yellow luminescent materials, which can be used as luminescent materials for yellow light devices, and can also be used as auxiliary materials for blue light in licensed white light devices.

[0128] Figure 2 The excitation and emission spectra of divalent platinum complex 1 at 77K are shown, and the wavelengths of all complexes are in the yellow phosphorescence region, indicating that this series of complexes are very good yellow light materials.

[0129] Figure 3 It is a luminescence spectrum diagram of different concentrations in the film of complex 1 in a specific embodiment of the present invention. The tested concentrations of doped complex 1 are 5%, 10%, and 20%. Its luminescence spectrum red-shifts with the increase of doping concentration, the peak shape does not change much, and there is no new luminescence peak; this shows that the structure has good single-molecule luminescence performance, and the luminescence spectrum can be fine-tuned by concentration in the yellow light range, and there is no aggregated luminescence.

[0130] Figure 4 The ultraviolet-visible absorption spectrum of the above-mentioned divalent platinum complex 13 in a dichloromethane solution is shown. According to the absorption spectrum, it can be known that the absorption spectrum has very strong absorption in the range of 250-450nm. Among them, the absorption below 350nm can be attributed to the π-π* transition centered on the ligand in the complex. Among them, the absorption peak after 350nm can be attributed to the valence state transfer transition (MLCT) transition between the central metal ion of the complex and the ligand. The energy absorption of such molecules is very efficient and can be used as the preferred molecular structure of doping material molecules. The wavelength below 250nm is the π-π* transition of the pyridine ring under spin permission, and 250nm-350nm is the π-π* transition of the carbazole ligand part; the absorption above the wavelength of 350nm comes from the πd-π* transition of the transfer state from the metal to the ligand.

[0131] Test Example 2

[0132] Characterization of band gap and related optical properties of complexes

[0133] The band gap and related optical properties of the divalent platinum complex 1 prepared in the embodiment of the present invention are characterized as follows: the band gap value (E g), the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) values ​​were measured by cyclic voltammetry (CV). The entire test process was carried out on a CHI600D electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd.) in a glove box (Lab2000, Etelux). A three-electrode system was formed with a Pt column as the working electrode, Ag / AgCl as the reference electrode, and a Pt wire as the auxiliary electrode. The medium used in the test process was a 0.1M tetrabutylammonium hexafluorophosphate (Bu4NPF6) dimethylformamide (DMF) solution, and the measured potentials were all measured with the added ferrocene (Fc) as the internal standard.

[0134] Table 2 shows the energy level data of the complexes.

[0135] Table 2

[0136] Complex <![CDATA[E HOMO (eV)]]> <![CDATA[E LUMO (eV)]]> Eg(eV) <![CDATA[E T1 (eV)]]> Complex 1 -5.23 -2.57 2.71 2.91 Complex 13 -5.21 -2.55 2.74 2.84 Complex 25 -5.25 -2.56 2.78 2.87 Comparative Example 1 -5.44 -2.32 3.12 2.77

[0137] In Table 2 above, λ is the peak wavelength of the divalent platinum complex dissolved in dichloromethane, FWHM is the half-peak width, and the triplet photon energy (E T1 ) is calculated from the formula 1240 / λ 0→1 Calculated from (λ 0→1 The triplet photon energy (E T1 ) are 2.91eV, 2.84eV and 2.87eV respectively, while the triplet photon energy (E T1 ) is 2.77 eV, indicating that the energy of the embodiment is higher.

[0138] Figure 5 For a single molecule of complex 1 1 H NMR spectrum shows that the complex 1 can exist independently and stably, and is easy to separate, purify and characterize. From the NMR spectrum, in addition to the stable structural characterization of the divalent platinum complex, the divalent platinum complex does not show any signal of aggregation, indicating that the divalent platinum complex molecules exist in a single molecule isolated state in the solution state.

[0139] Figure 6 This is the mass spectrometry characterization diagram of the molecule of complex 1. The mass spectrometry molecule shows that the molecular signal shows an M / C peak of 777.7, which is consistent with the molecular ion peak of complex 1, indicating that the structure of the complex is the designed structure.

[0140] Application Example 1

[0141] Application of divalent platinum complexes in OLED devices

[0142] The embodiment of the present invention also provides an organic optoelectronic device, which includes a light-emitting layer, and the light-emitting layer contains the divalent platinum complex prepared in the above embodiment. Optionally, the divalent platinum complex is a light-emitting material, a host material or a guest material in the light-emitting layer of the organic optoelectronic device.

[0143] Figure 7 : is a yellow phosphor device structure diagram, showing the structure diagram of an OLED light-emitting device, which includes a divalent platinum complex prepared in the above embodiment. The OLED device includes an anode, which is generally a conductive transparent material, such as indium tin oxide (ITO), a hole injection layer (P-HIL), a hole transport layer (HTL), a light-emitting layer (EML), an electron transport layer (ETL) and a metal cathode layer (Cathode). Among them, EML can be a light-emitting material including one or more emitters and a host; EIL refers to an electron injection layer, which can be regarded as a part of ETL; HIL can be regarded as a part of HTL. In addition, in addition to the core structure of the device, a cathode cover layer (CPL) can be added, whose function is to adjust the optical path to improve the light extraction efficiency.

[0144] In the device example, complexes 1, 13 and 25 are respectively doped into the host material as light-emitting materials to prepare OLED devices, with a doping amount of 5%. The OLED devices are prepared, ITO is the anode of the OLED device, and Al is the cathode of the OLED device.

[0145] The device structure is:

[0146] ITO / HIL(10nm) / HTL(140nm) / EML(25nm) / ETL(35nm) / EIL(10nm) / Al; wherein, the HIL hole injection layer may be, but not limited to, materials such as HATCN and Re2O3; the HTL is a hole transport layer, which may be, but not limited to, materials such as TAPC, NPD, TCTA, PT301, and OJHS006; the EML layer is a light-emitting layer complex: the main material = 5%: 95% blended layer, the main material may be, but not limited to, materials such as CBP, mCBP, 2,6mCPy, and mCP; the ETL layer is an electron transport layer, which may be, but not limited to, materials such as TmPyPb, TPBi, DPPS, Bphen, BmPyPb, and DBFTrz; the EIL layer is an electron injection layer, which may be, but not limited to, materials such as LiQ and LiF. The device structure includes, but is not limited to, the materials mentioned above.

[0147] HATCN (Chinese name: 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene material, English name: 2,3,6,7,10,11-Hexaazatriphenylenehexacabonitrile);

[0148] Re2O3 (Chinese name: molybdenum trioxide, English name: Molybdenum (VI) oxide);

[0149] TAPC (Chinese name: 4,4′-cyclohexylbis[N,N-di(4-methylphenyl)aniline], English name: 4,4′-cyclohexylidenebis[N,N-bis(p-tolyl)aniline];

[0150] NPD (Chinese name: N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, English name: N,N'-Bis-(1-naphthalenyl)-N,N'-bis-phenyl-(1,1'-biphenyl)-4,4'-diamine)

[0151] TCTA (Chinese name: 4,4′,4”-Tris(carbazol-9-yl)triphenylamine, English name: 4,4′,4”-Tris(carbazol-9-yl)triphenylamine)

[0152] PT301 (Chinese name: 4,4'-Bis[N,N-di(biphenyl-4-yl)amino]-1,1'-biphenyl, English name: 4,4'-Bis[N,N-di(biphenyl-4-yl)amino]-1,1'-biphenyl)

[0153] OJHS006 (Chinese name: 2,6-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)pyridine, English name: 2,6-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)pyridine)

[0154] CBP (Chinese name: 4,4'-di(9-carbazolyl)biphenyl, English name: 4,4'-Bis(9-carbazolyl)-1,1'-biphenyl);

[0155] mCBP (Chinese name: 3,3'-di(9H-carbazol-9-yl)-1,1'-biphenyl, English name: 3,3'-Di(9H-carbazol-9-yl)-1,1'-biphenyl (purified by sublimation)

[0156] 2,6mCPy (Chinese name: 2,6-di(9-carbazol-9-yl)pyridine, English name: 2,6-Di(9H-carbazol-9-yl)pyridine)

[0157] mCP (Chinese name: 1,3-di-9-carbazolylbenzene, English name: 1,3-Di-9-carbazolylbenzene)

[0158] LiQ (Chinese name: 8-Hydroxyquinolinolato-lithiuM)

[0159] LiF (Chinese name: lithium fluoride, English name: Lithium fluoride)

[0160] TmPyPb (Chinese name: 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1"-terphenyl]-3,3"-diyl]bipyridine, English name: 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene)

[0161] TPBi (Chinese name: 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, English name: 1,3,5-Tris(1-phenyl-1H-benzimidazol-2-yl)benzene);

[0162] DPPS (Chinese name: Diphenylbis[4-(pyridin-3-yl)phenyl]silane, English name: Diphenylbis(4-(pyridin-3-yl)phenyl)silane)

[0163] Bphen (Chinese name: 4,7-diphenyl-1,10-phenanthroline, English name: 4,7-diphenyl-1,10-phenanthroline)

[0164] BmPyPb (Chinese name: 1,3-bis(3,5-dipyridin-3-ylphenyl)benzene, English name: 1,3-bis[3,5-di(pyridin-3-yl)phenyl]benzene)

[0165] DBFTrz (Chinese name: 2,8-bis(4,6-diphenyl-1,3,5-triazin-2-yl)dibenzo[b,d]furan, English name: 2,8-bis(4,6-diphenyl-1,3,5-triazin-2-yl)dibenzo[b,d]furan)

[0166] The crucible containing OLED organic materials and the crucible containing aluminum particles are placed on the positions of the organic evaporation source and the inorganic evaporation source in turn. The cavity is closed, and the initial vacuum and high vacuum steps are performed to make the vacuum degree of the evaporation inside the OLED evaporation equipment reach 10E-7Torr.

[0167] OLED evaporation film forming method: open the OLED organic evaporation source, preheat the OLED organic material to 100℃, and the preheating time is 15 minutes to ensure further removal of water vapor in the OLED organic material. Then, the organic material to be evaporated is quickly heated, and the baffle above the evaporation source is opened until the evaporation source of the material has organic material running out. At the same time, when the crystal oscillator detector detects the evaporation rate, the temperature is slowly increased by 1-5℃ until the evaporation rate stabilizes at 1A / second. The baffle directly below the mask plate is opened to form the OLED film. When the computer observes that the organic film on the ITO substrate reaches the preset film thickness, the mask plate baffle and the baffle directly above the evaporation source are closed, and the evaporation source heater of the organic material is closed. The evaporation process of other organic materials and cathode metal materials is as described above. UV epoxy resin is used for light-curing packaging. The encapsulated samples are tested for IVL performance, and the IVL equipment is tested using Mc Science M6100.

[0168] In the present invention, the complexes 1, 13 and 25 prepared in the embodiment are used as yellow phosphorescent doping materials in the light-emitting layer to prepare a yellow phosphorescent device. When the divalent platinum complex is used as a doping material in an OLED device, a yellow phosphorescent device is prepared by a steam distillation method. The structure of device 1 is (ITO, 95nm) / 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC, 30nm) / 9,9'-(1,3-phenyl)bis-9H-carbazole (mCP, 10nm) / mCP: complex (20:1, 20nm) / bis[2-((oxy)diphenylphosphino)phenyl]ether (DPE PO, 5nm) / 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1"-terphenyl]-3,3"-diyl]bipyridine (TmPyPB, 40nm) / lithium fluoride (LiF, 1nm) / aluminum (Al, 100nm), wherein ITO is the anode, TAPC is the hole transport material layer 1, mCP is the hole transport layer 2 and the main material of the light-emitting layer, DPEPO and TmPyPB are the electron transport layers, and Al is the cathode.

[0169] The electroluminescence spectrum is Figure 8 As shown, Figure 8This is the luminescence spectrum of the yellow phosphorescent device using complex 1 in the specific embodiment of the present invention; the peak wavelength of the yellow phosphorescent device prepared by complex 1 is 566nm, and the half-peak width reaches 96nm, which is a very good yellow light range. The maximum current efficiency and energy efficiency (PE) of the device is 28.8lmW -1 , the highest current efficiency (CE) is 60.5cdA -1 , and the highest external quantum efficiency (EQE) reaches 18.7%, which is a high-efficiency light-emitting device.

[0170] In the structure of the OLED light-emitting device, the light-emitting layer may contain one or more divalent platinum complexes provided by the present invention, and may be selectively associated with a host material and one or more doping materials. The present specification provides a dual-doped (blue light + yellow phosphorescent) white phosphorescent device, and the structure of device 2 is as follows (ITO, 95nm) / 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline](TAPC, 30nm) / 9,9'-(1,3-phenyl)bis-9H-carbazole (mCP, 10nm) / mCP: Pt(ppzOczpy-4m): complex 1 (100:5:1, 20nm) / bis[2-((oxygen) [(1,2-diphenylphosphino)phenyl]ether (DPEPO, 5nm) / 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1"-terphenyl]-3,3"-diyl]bipyridine (TmPyPB, 40nm) / lithium fluoride (LiF, 1nm) / aluminum (Al, 100nm), where the structure and specific parameters of Pt(ppzOczpy-4m) can be referred to the literature High-color-purity and efficient solution-processable bluephosphorescent light-emitting diodes with Pt(II)complexes featuring 3 ππ* transitions Huili Ma, Kang Shen, Yipei Wu, Fang Xia, Feiling Yu, Zhengyi Sun, Chunyue Qian, Qiming Peng, Hong-Hai Zhang, Cong You, a Guohua Xie, Xiao-Chun Hang and Wei Huang, Mater. Chem. Front. 2019, 3, 2448-2454.

[0171] Fig. 9The luminescence spectrum of the white phosphorescent device prepared using complex 1 is shown, with a half-peak width of 150nm and a CIE coordinate value of (0.33, 0.33), which covers the blue, green and red luminescence ranges very well. The device has a maximum current efficiency and energy efficiency (PE) of 38.1lmW -1 , the highest current efficiency (CE) is 44.6cdA -1 , and the highest external quantum efficiency (EQE) reaches 21.2%, which is a high-efficiency light-emitting white phosphor device. Fig. 9 The electroluminescence spectrum of the device with a structure of 5% by mass of blue light material Pt (ppzOczpy-4m) and 1% by mass of yellow phosphorescent doping material divalent platinum complex 1 doped in the light-emitting layer relative to the main material shows that the luminescence peak has a red shift in the blue light part and a blue shift in the long wavelength part relative to its photoluminescence peak in the PMMA medium, which shows that the two doping materials can achieve good energy transfer and synergistic light emission. A high-efficiency white phosphorescent device is obtained.

[0172] White phosphorescent devices were prepared using the device 2 structure and three demonstration complexes. The device results are shown in Table 3: Device luminescence performance.

[0173] Table 3

[0174]

[0175] Table 3 shows the luminescence performance data of the white phosphorescent light-emitting devices prepared by various complexes. Under the same conditions, the efficiency of the light-emitting device is consistent with the luminescence quantum efficiency of the divalent platinum complex itself, and at 1000 cd·m -2 The white phosphorescence effect of the light-emitting device is basically consistent with the light emission of a single yellow phosphorescent material. It is obvious that the spectrum of the complex 1 and the blue light doping material under the sub-device structure is wider, which is more suitable for white phosphorescence applications.

[0176] The present invention uses an exemplary example to illustrate that the structural formula (I) can be used as a yellow phosphorescent doping material to prepare a single-doped yellow phosphorescent device and a double-doped white phosphorescent device with a blue phosphorescent material, wherein each material is not limited to the exemplary structure; based on the application, the device structure can be either a bottom-emitting device or a top-emitting device. The ETL layer and the HTL may also contain one or more transport layer materials, and there may be another charge injection layer near the divalent platinum complex and the electrode. The materials of the injection layer may include an EIL (electron injection layer), a HIL (hole injection layer) and a CPL (cathode cover layer), which may be in the form of a single layer or dispersed in an electron or hole transport material. The host material may be any suitable host material known in the art. The luminescent color of the OLED is determined by the luminescent energy (optical energy gap) of the luminescent layer material, and the luminescent energy (optical energy gap) of the luminescent layer material can be tuned by tuning the electronic structure of the emitting divalent platinum complex and / or the host material as described above. The hole transport material in the HTL layer and the electron transport material in the ETL layer may include any suitable hole transporter known in the art. The divalent platinum complexes provided by embodiments of the present invention may exhibit phosphorescence. Phosphorescent OLEDs (ie, OLEDs with phosphorescent emitters) generally have higher device efficiencies than other OLEDs such as fluorescent OLEDs.

[0177] Test Example 3

[0178] Current efficiency measurement of yellow phosphorescent device prepared by complex 1

[0179] Fig.10 Schematic diagram of the relationship between current density and power efficiency of a yellow phosphorescent device using complex 1 in a specific embodiment of the present invention; Fig.10 It can be seen that the device has a high power efficiency and a certain roll-off under high current, which means that there is still a lot of room for optimization of the device and the luminescence performance based on this complex can be further improved.

[0180] Test Example 4

[0181] Power efficiency measurement of yellow phosphorescent device prepared from complex 1

[0182] Fig.11 Schematic diagram of the relationship between the current density and the current efficiency of the yellow phosphorescent device using the complex 1 in a specific embodiment of the present invention; Fig.11 It can be seen that the highest current efficiency of the device exceeds 60cd / A, and there is a certain roll-off under high current, which means that there is still a lot of room for optimization of the device, and the luminescence performance based on this complex can be further improved.

[0183] Test Example 5

[0184] Determination of external quantum efficiency of yellow phosphorescent device prepared by complex 1

[0185] Fig.12 Schematic diagram of the relationship between the current density and the external quantum efficiency of the yellow phosphorescent device using the complex 1 in a specific embodiment of the present invention; Fig.12 It can be seen that the highest external quantum of the device is less than 20%. According to the device light extraction coupling efficiency of 20-25%, it means that the device has not yet reached a large room for optimization, and the luminescence performance based on this complex can be further improved.

[0186] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A divalent platinum complex, characterized in that The divalent platinum complex has a structure shown in formula (I): Among them, R a , R b and R c The same or different, each independently present or absent, monosubstituted or polysubstituted, and R a , R b and R c Each is independently selected from a single atomic substituent or a polyatomic substituent; the single atomic substituent includes a hydrogen atom and its isotope atoms or a halogen atom; the polyatomic substituent includes a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted cycloalkyl group, a cycloalkenyl group, a heteroaryl group, an alkenyl group, an alkynyl group, an amino group, a hydroxyl group, a thiol group, a nitro group, a cyano group, a sulfinyl group, a sulfonyl group, a carboxyl group, a hydrazine group, an alkoxy group, an aryloxy group, an ester group, an alkoxycarbonyl group, an amide group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfamoyl group, a carbamoyl group, an alkylthio group, a urea group, a phosphoramide group, a silyl group, a polymer group and one or more of the above substituents containing isotope atoms.

2. The divalent platinum complex according to claim 1, wherein The substituted alkyl group is selected from one or more of an aryl-substituted alkyl group, a fluorine-substituted alkyl group and a haloalkyl group; and / or, the substituted aryl group is selected from alkyl-substituted aryl groups and / or aryl-substituted aryl groups; and / or, the amino group includes one or more of a monoalkylamino group, a dialkylamino group, a monoarylamino group and a diarylamino group; And / or, the cyano group is an isocyano group.

3. The divalent platinum complex according to claim 1 or 2, wherein R a , R b and R c Each is independently selected from deuterium, -CDH2, -CD2H, -CD3, -CDR1R2, -CD2R1, wherein R1 and R2 are each independently selected from one or more of substituted or unsubstituted alkyl, substituted or unsubstituted aryl, alkyl-substituted aryl, aryl-substituted aryl, cycloalkyl, cycloalkenyl, heteroaryl, alkenyl, alkynyl, amino, monoalkylamino, dialkylamino, monoarylamino, diarylamino, alkoxy, aryloxy, haloalkyl, ester, alkoxycarbonyl, amide, alkoxycarbonylamino, aryloxycarbonylamino, sulfamoyl, carbamoyl, alkylthio, urea, phosphoramide, silyl and polymer groups.

4. The divalent platinum complex according to any one of claims 1 to 3, wherein The alkyl group is C1-C 30 The alkyl group is preferably C1-C 24 The alkyl group; and / or, the isotope atoms are deuterium atoms and / or tritium atoms; And / or, the halogen atom is selected from one or more of a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

5. The divalent platinum complex according to any one of claims 1 to 4, wherein R a , R b and R c each independently selected from the group consisting of methyl, deuterated methyl, benzyl, diphenylmethyl, triphenylmethyl, ethyl, 2-phenylethyl, 2,2-phenylethyl, 2,2,2-trifluoroethyl, propyl, isopropyl, 3,3,3-trifluoropropyl, 1,1,1,3,3,3-hexafluoro-2-propyl, butyl, isobutyl, hexafluoroisobutyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, phenyl, 2-methylphenyl, 2-isopropylphenyl, 2-ethylphenyl, 4-methylphenyl, phenyl, 4-isopropylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 2,3-dimethylphenyl, 2,3-diethylphenyl, 2,3-diisopropylphenyl, 2,3-diisobutylphenyl, 2,3-dicyclohexylphenyl, 2,3-dicyclopropylphenyl, 2,3-dicyclobutylphenyl, 2,3-dicyclopentylphenyl, 2,4-dimethylphenyl, 2,4-diethylphenyl, 2,4-diisopropylphenyl, 2,4-diisobutylphenyl, 2,4-dicyclohexylphenyl , 2,4-dicyclopropylphenyl, 2,4-dicyclobutylphenyl, 2,4-dicyclopentylphenyl, 2,6-dimethylphenyl, 2,6-diethylphenyl, 2,6-diisopropylphenyl, 2,6-diisobutylphenyl, 2,6-dicyclohexylphenyl, 2,6-dicyclopropylphenyl, 2,6-dicyclobutylphenyl, 2,6-dicyclopentylphenyl, 3,5-dimethylphenyl, 3,5-diethylphenyl, 3,5-diisopropylphenyl, 3,5-diisobutylphenyl, 3, One or more of 5-dicyclohexylphenyl, 3,5-dicyclopropylphenyl, 3,5-dicyclobutylphenyl, 3,5-dicyclopentylphenyl, 2,3,5,6-tetramethylphenyl, 2,4,6-trimethylphenyl, 2,4,6-triethylphenyl, 2,4,6-triisopropylphenyl, 2,4,6-triisobutylphenyl, 2,4,6-tricyclohexylphenyl, 2,4,6-tricyclopropylphenyl, 2,4,6-tricyclobutylphenyl and 2,4,6-tricyclopentylphenyl.

6. The divalent platinum complex according to any one of claims 1 to 5, wherein The divalent platinum complex is selected from at least one of the complexes 1-30 shown below:

7. A method for preparing a divalent platinum complex, characterized in that: The preparation method comprises: (1) performing a fragment coupling reaction of a first ligand represented by formula (a) and 9-(pyridin-2-yl)-9H-carbazole-2-ol represented by formula (b) to obtain a second ligand represented by formula (c); (2) in the presence of a platinum salt, subjecting the second ligand represented by formula (c) to a metal coordination cyclization reaction to obtain a divalent platinum complex represented by formula (I); Among them, R in formula (a), formula (c) and formula (I) a , R b and R c Same as the definition in any one of claims 1 to 6.

8. The preparation method according to claim 7, wherein: The coupling reaction of the fragments further comprises carrying out the reaction in the presence of cuprous bromide, 2,2,6,6-4-methyl-3,5-heptanedione, potassium hydroxide and N-methylpyrrolidone; and / or, relative to 0.5-5 mL of N-methylpyrrolidone, the molar amount of the ligand represented by formula (a) is 0.05-10 mmol, the molar amount of 9-(pyridin-2-yl)-9H-carbazole-2-ol represented by formula (b) is 0.15-15 mmol, the molar amount of cuprous bromide is 0.05-5 mmol, the molar amount of 2,2,6,6-4-methyl-3,5-heptanedione is 0.05-5 mmol, and the molar amount of potassium hydroxide is 0.1-10 mmol; And / or, the coupling reaction conditions of the fragments include: stirring for 24-72 hours at a temperature of 80-250° C. under a N 2 atmosphere.

9. The preparation method according to claim 7, wherein: The metal coordination cyclization reaction further comprises carrying out the reaction in the presence of acetic acid; And / or, the platinum salt is potassium chloroplatinite; and / or, relative to 5-100 mL of acetic acid, the molar amount of the second ligand represented by formula (c) is 0.01-10 mmol, and the molar amount of potassium chloroplatinite is 0.01-10 mmol; And / or, the conditions of the metal coordination cyclization reaction include: first stirring at a temperature of 20-60° C. for 12-48 h under a N2 atmosphere; Then raise the temperature to 100-180°C and stir for 12-60h.

10. A divalent platinum complex prepared by the preparation method according to any one of claims 7 to 9.

11. Use of the divalent platinum complex according to any one of claims 1 to 6 and 10 in electroluminescent materials and / or photoluminescent materials.

12. The use according to claim 11, wherein: The divalent platinum complex is used as a yellow phosphorescent luminescent material and / or a phosphorescent luminescent material.

13. Use of the divalent platinum complex according to any one of claims 1 to 6 and 10 in organic optoelectronic devices for lighting and / or display.

14. An organic optoelectronic device, characterized in that: The organic optoelectronic device comprises a light-emitting layer, wherein the light-emitting layer comprises the divalent platinum complex according to any one of claims 1 to 6 and 10.

15. The organic optoelectronic device according to claim 14, wherein: The organic photoelectric device further comprises a substrate, an anode layer, a hole transport layer, an electron transport layer and a metal cathode layer, wherein the electron transport layer and / or the hole transport layer comprises the divalent platinum complex according to any one of claims 1-6 and 10.

16. The organic optoelectronic device according to claim 14 or 15, wherein: The divalent platinum complex is a light-emitting material, a host material or a guest material in the light-emitting layer.

Images