Ink, luminescent device and preparation method thereof

Abstract

The invention provides ink, a luminescent device and a preparation method thereof, the ink comprises an organic luminescent material, a diluent and a solvent, and the diluent comprises one or more of vinyl fatty ether, acrylic fatty ester, fatty alcohol, aromatic alcohol and fatty acid vinyl ester. According to the ink disclosed by the invention, the organic light-emitting material is diluted by adopting the specific diluent, so that the spreadability of the ink of the light-emitting layer can be effectively improved, and the light-emitting efficiency and the performance stability of a light-emitting device are improved; and the uniformity of the light-emitting layer after ink coating can be improved, so that the preparation efficiency of the light-emitting device is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of organic light emitting diodes, and in particular to an ink, a light emitting device and a preparation method thereof. Background Art

[0002] As an important planar light source technology, organic light-emitting diodes (OLEDs) have been widely used in the field of light-emitting devices and lighting. OLEDs have the advantages of high contrast, fast response, and flexibility through the electroluminescent properties of organic materials, so they have attracted much attention. However, the further development of OLED technology still faces some challenges.

[0003] In traditional OLED production, one of the key steps in preparing the light-emitting layer is to apply the organic light-emitting material in the form of ink of a specific concentration to the substrate by inkjet printing or solution spin coating. These inks contain organic light-emitting materials as well as components such as solvents and additives. In the known technology, a fixed ink concentration is usually used to prepare the light-emitting layer, which has some significant defects and limitations. For example, the ink has poor spreadability, the product has low luminous efficiency, and unstable performance.

[0004] Fixed-concentration luminescent layer inks are usually not flexible enough to adapt to different preparation conditions and requirements, which may lead to poor ink spreading and insufficient uniformity during the coating process. Poor ink spreading seriously affects the efficient preparation of OLEDs and hinders the improvement of luminous efficiency and stability of OLED devices.

[0005] Therefore, how to regulate the spreadability of the light-emitting layer ink to improve the luminous efficiency and product performance stability of OLED devices has become one of the important research directions in this field. Summary of the invention

[0006] The present invention is made in view of the above-mentioned problems, and one of its purposes is to provide an ink having good spreadability, which can improve the uniformity and stability of the light-emitting layer, thereby improving the luminous efficiency and performance stability of the light-emitting device.

[0007] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides an ink, which includes an organic light-emitting material, a diluent and a solvent, and the diluent includes one or more of vinyl fatty ether, acrylic fatty ester, fatty alcohol, aromatic alcohol and fatty acid vinyl ester.

[0008] In some embodiments, the mass ratio of the organic light-emitting material to the diluent in the ink is 96-99:1-4.

[0009] In some embodiments, the concentration of the organic light-emitting material in the ink is 10 mg / mL to 30 mg / mL.

[0010] In some embodiments, the vinyl fatty ether includes a vinyl fatty ether having a carbon number of 2 to 6 in the fatty group.

[0011] In some embodiments, the aliphatic acrylate includes an aliphatic acrylate having an aliphatic group with 1 to 10 carbon atoms.

[0012] In some embodiments, the fatty alcohol comprises a fatty alcohol having 2 to 4 carbon atoms.

[0013] In some embodiments, the aromatic alcohol includes an aromatic alcohol having 6 to 12 carbon atoms.

[0014] In some embodiments, the fatty acid vinyl ester includes fatty acid vinyl ester in which the carbon number of the fatty acid is 2 to 24.

[0015] In some embodiments, the vinyl aliphatic ether includes one or more of vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether and vinyl cyclohexyl ether.

[0016] In some embodiments, the aliphatic acrylate includes one or more of isobutyl acrylate, butyl acrylate, isobornyl acrylate, methyl acrylate, ethyl acrylate and cyclohexyl acrylate.

[0017] In some embodiments, the fatty alcohol includes one or more of isopropanol, n-butanol, anhydrous ethanol and propylene glycol.

[0018] In some embodiments, the aromatic alcohol includes one or more of benzyl alcohol, phenylethyl alcohol and phenylpropanol.

[0019] In some embodiments, the fatty acid vinyl ester includes one or more of vinyl acetate, vinyl oleate, and vinyl stearate.

[0020] In some embodiments, the solvent includes one or more of ethylene glycol, glycerol, ethyl benzoate, isopropyl benzoate, n-butyl lactate, o-dichlorobenzene, tetralin, mesitylene, methyl benzoate, toluene, xylene, chlorobenzene, chloroform, tetrahydrofuran, acetonitrile, dichloromethane, cyclohexylbenzene and tetralin.

[0021] In some embodiments, the diluent is vinyl ethyl ether, and the mass ratio of the organic light-emitting material to the diluent in the light-emitting layer ink is 97-98:2-3.

[0022] In some embodiments, the diluent is vinyl ethyl ether, and the mass ratio of the organic light-emitting material to the diluent in the light-emitting layer ink is 98:2.

[0023] In some embodiments, the diluent is vinyl acetate, and the mass ratio of the organic light-emitting material to the diluent in the light-emitting layer ink is 98-99:1-2.

[0024] In some embodiments, the diluent is vinyl acetate, and the mass ratio of the organic light-emitting material to the diluent in the light-emitting layer ink is 98:2.

[0025] In some embodiments, the organic light-emitting material includes an anthracene-based thermoexciton material.

[0026] In some embodiments, the anthracene-based thermoexciton material includes one or more of PABPP, mPAC, PAC, PAIDO, PABP and PATPA.

[0027] In some embodiments, the viscosity of the ink at 20° C. is 0.1 cP to 20 cP.

[0028] In some embodiments, the surface tension of the ink is 20 mN / m to 50 mN / m.

[0029] A second aspect of the present invention provides a method for preparing a light-emitting device, the method comprising the following steps:

[0030] providing a first electrode;

[0031] Depositing a light-emitting layer ink on the first electrode to form a light-emitting layer;

[0032] Depositing a second electrode on the light-emitting layer to obtain a light-emitting device;

[0033] Wherein, the luminous layer ink is selected from the ink of the first aspect of the present invention.

[0034] In some embodiments, depositing a light-emitting layer ink on the first electrode to form a light-emitting layer comprises the following steps:

[0035] The light-emitting layer ink is deposited on the first electrode by a solution method, and the light-emitting layer is formed after annealing.

[0036] In some embodiments, the solution method includes inkjet printing, spin coating, and pad printing.

[0037] In some embodiments, the annealing temperature is 100° C. to 150° C., and the annealing time is 5 min to 30 min.

[0038] The third aspect of the present invention provides a light-emitting device, comprising a first electrode, a light-emitting layer and a second electrode stacked in sequence, wherein the material forming the light-emitting layer comprises the ink of the first aspect of the present invention; or, the light-emitting device is prepared by the preparation method of the second aspect of the present invention.

[0039] In some embodiments, the thickness of the light-emitting layer is 10 nm to 50 nm.

[0040] In some embodiments, the materials of the first electrode and the second electrode each independently include one or more of a metal, a carbon material and a metal oxide, the metal including one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb and Mg; the carbon material includes one or more of graphite, carbon nanotubes, graphene and carbon fiber; the metal oxide includes a doped or undoped metal oxide, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO, or includes a composite electrode in which a metal is sandwiched between doped or undoped transparent metal oxides, and the composite electrode includes one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2 and TiO2 / Al / TiO2.

[0041] In some embodiments, the light-emitting device further includes a hole injection layer and / or a hole transport layer, the hole injection layer and the hole transport layer are arranged between the first electrode and the light-emitting layer, and the materials of the hole injection layer and the hole transport layer independently include one or more of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tri(N-3-methylphenyl-Nphenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tinides, doped graphene, undoped graphene and C60.

[0042] In some embodiments, the light-emitting device further includes an electron transport layer, which is disposed between the light-emitting layer and the second electrode. The material of the electron transport layer includes an inorganic material and / or an organic material. The inorganic material includes one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate. The doped elements include aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, One or more of nickel, zirconium, cerium, and gadolinium; the organic material includes one or more of 8-hydroxyquinoline aluminum, diphenyl [4- (triphenylsilyl) phenyl] phosphine oxide, 1,3,5-tri (3-pyridyl-3-phenyl) benzene, 2- (4'-tert-butylphenyl) -5- (4'-biphenyl) -1,3,4- oxadiazole, 8-hydroxyquinoline beryllium, 1,2,4-triazole derivatives, 2,7-bis (diphenylphosphinyl) -9,9'-spirobis [fluorene], 1,3,5-tri (1-phenyl-1H-benzimidazol-2-yl) benzene, 4,6-bis (3,5-di (3-pyridyl) phenyl) -2-methylpyrimidine and 4,7-diphenyl -1,10-phenanthroline.

[0043] In some embodiments, the light-emitting device further comprises an electron injection layer, which is disposed between the light-emitting layer and the second electrode. The material of the electron injection layer comprises an inorganic material and / or an organic material. The inorganic material comprises metallic lithium, lithium fluoride, magnesium fluoride, and one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate. The doped elements comprise aluminum, magnesium, lithium, manganese, One or more of yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the organic material includes one or more of 8-hydroxyquinoline aluminum, diphenyl [4- (triphenylsilyl) phenyl] phosphine oxide, 1,3,5-tri (3-pyridyl-3-phenyl) benzene, 2- (4'-tert-butylphenyl) -5- (4'-biphenyl) -1,3,4- oxadiazole, 8-hydroxyquinoline beryllium, 1,2,4-triazole derivatives, 2,7-bis (diphenylphosphinyl) -9,9'-spirobis [fluorene], 1,3,5-tri (1-phenyl-1H-benzimidazol-2-yl) benzene, 4,6-bis (3,5-di (3-pyridyl) phenyl) -2-methylpyrimidine and 4,7-diphenyl -1,10-phenanthroline.

[0044] Compared with the prior art, the present invention has at least the following beneficial effects: by using a specific type of diluent in the light-emitting layer ink to dilute the organic light-emitting material, the spreadability and film-forming properties of the light-emitting layer ink can be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to better describe and illustrate the embodiments or examples provided by the present invention, reference may be made to one or more drawings. The additional details or examples used to describe the drawings should not be considered as limiting the scope of the disclosed invention, the embodiments or examples currently described, and any of the best modes of these inventions currently understood. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0046] Figure 1 Schematic diagram of the structure of light-emitting devices in some embodiments of the present invention;

[0047] Figure 2 The graphs show the relationship between external quantum efficiency and current density of the light-emitting devices of some device embodiments and device comparison examples of the present invention.

[0048] Description of reference numerals:

[0049] 10. Light-emitting device; 11. First electrode; 12. Hole injection layer; 13. Hole transport layer; 14. Light-emitting layer; 15. Electron transport layer; 16. Electron injection layer; 17. Second electrode. DETAILED DESCRIPTION

[0050] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the present invention, etc. can be purchased from the market or can be prepared by existing methods.

[0052] In traditional OLED production, a fixed ink concentration is usually used to prepare the light-emitting layer. This method easily leads to poor spreading and uniformity of the light-emitting layer ink during the coating process, which in turn leads to low luminous efficiency and unstable performance of the product. The poor spreading of the ink seriously affects the efficient preparation of OLEDs and hinders the improvement of the luminous efficiency and stability of OLED devices. In this regard, the present invention improves and adjusts the composition ratio of the light-emitting layer ink so that the light-emitting layer ink has better spreading, thereby improving the uniformity and stability of the light-emitting layer, and improving the luminous efficiency and performance stability of the light-emitting device.

[0053] An embodiment of the present invention provides a light-emitting layer ink, which includes an organic light-emitting material, a diluent and a solvent, wherein the diluent includes one or more of vinyl fatty ether, acrylic fatty ester, fatty alcohol, aromatic alcohol and fatty acid vinyl ester. By using a specific diluent in the light-emitting layer ink to dilute the organic light-emitting material, the spreadability and film-forming properties of the light-emitting layer ink can be effectively improved, thereby improving the luminous efficiency and performance stability of the light-emitting device. Moreover, the spreadability of the light-emitting layer ink is improved, and the uniformity of the light-emitting layer ink after coating can also be improved, thereby improving the preparation efficiency of the light-emitting device.

[0054] In some embodiments, the mass ratio of the organic light-emitting material to the diluent in the light-emitting layer ink is 96-99:1-4. When the proportion of the added diluent is too large, the light-emitting efficiency of the light-emitting device will be affected because the diluent itself does not emit light; when the proportion of the added diluent is too small, the spreadability of the light-emitting layer ink cannot be effectively improved. Controlling the mass ratio of the organic light-emitting material to the diluent in the light-emitting layer ink within the above-mentioned ratio range can better improve the light-emitting efficiency and performance stability of the light-emitting device.

[0055] In some embodiments, the concentration of the organic light-emitting material in the light-emitting layer ink is 10 mg / mL to 30 mg / mL. It is understood that the concentration of the organic light-emitting material in the light-emitting layer ink can be 10 mg / mL, 12 mg / mL, 15 mg / mL, 18 mg / mL, 20 mg / mL, 22 mg / mL, 25 mg / mL, 28 mg / mL, 30 mg / mL, and any value between the ranges formed by any two of the above values.

[0056] In some embodiments, vinyl fatty ethers include vinyl fatty ethers having a fatty group with 2 to 6 carbon atoms; acrylic fatty esters include acrylic fatty esters having a fatty group with 1 to 10 carbon atoms; fatty alcohols include fatty alcohols having 2 to 4 carbon atoms; aromatic alcohols include aromatic alcohols having 6 to 12 carbon atoms; and fatty acid vinyl esters include fatty acid vinyl esters having a fatty acid with 2 to 24 carbon atoms.

[0057] In some embodiments, the diluent vinyl fatty ether includes one or more of vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether and vinyl cyclohexyl ether; the diluent acrylic fatty ester includes one or more of isobutyl acrylate, butyl acrylate, isobornyl acrylate, methyl acrylate, ethyl acrylate and cyclohexyl acrylate; the diluent fatty alcohol includes one or more of isopropanol, n-butanol, anhydrous ethanol and propylene glycol; the diluent aromatic alcohol includes one or more of benzyl alcohol, phenylethyl alcohol and phenylpropanol; the fatty acid vinyl ester includes one or more of vinyl acetate, vinyl oleate and vinyl stearate; the solvent includes one or more of ethylene glycol, glycerol, ethyl benzoate, isopropyl benzoate, n-butyl lactate, o-dichlorobenzene, tetralin, mesitylene, methyl benzoate, toluene, xylene, chlorobenzene, chloroform, tetrahydrofuran, acetonitrile, dichloromethane, cyclohexylbenzene and tetralin.

[0058] In some embodiments, the diluent is vinyl ethyl ether, and the mass ratio of the organic light-emitting material to the diluent in the light-emitting layer ink is 97-98:2-3. When vinyl ethyl ether is used as the diluent, and the organic light-emitting material and vinyl ethyl ether are mixed in a ratio of 97-98:2-3, the spreadability of the light-emitting layer ink can be further improved, and the luminous efficiency and performance stability of the light-emitting device can be further improved.

[0059] In some embodiments, the diluent is vinyl ethyl ether, and the mass ratio of the organic light-emitting material to the diluent in the light-emitting layer ink is 98: 2. When vinyl ethyl ether is used as the diluent, and the organic light-emitting material and vinyl ethyl ether are mixed in a ratio of 98: 2, the spreadability of the light-emitting layer ink can be further improved, and the luminous efficiency and performance stability of the light-emitting device can be better improved.

[0060] In some embodiments, the diluent is vinyl acetate, and the mass ratio of the organic light-emitting material to vinyl acetate in the light-emitting layer ink is 98-99:1-2. When vinyl acetate is used as the diluent, and the organic light-emitting material and vinyl acetate in the light-emitting layer ink are mixed in a ratio of 98-99:1-2, the spreadability of the light-emitting layer ink can be further improved, and the luminous efficiency and performance stability of the light-emitting device can be further improved.

[0061] In some embodiments, the diluent is vinyl acetate, and the mass ratio of the organic light-emitting material to vinyl acetate in the light-emitting layer ink is 98:2. When vinyl acetate is used as the diluent, and the organic light-emitting material and vinyl acetate in the light-emitting layer ink are mixed in a ratio of 98:2, the spreadability of the light-emitting layer ink can be further improved, and the luminous efficiency and performance stability of the light-emitting device can be further improved.

[0062] In some embodiments, the organic light-emitting material includes an anthracene-based thermoexciton material, and the anthracene-based thermoexciton material includes one or more of PAC (CAS No.: 2414547-46-7), mPAC (CAS No.: 2376325-67-4), PABP (CAS No.: 2378287-83-1), PAIDO (CAS No.: 2378287-85-3), PABPP (CAS No.: 2639255-13-1) and PATPA (CAS No.: 2420454-95-9). The above-mentioned anthracene-based thermoexciton material has high orientation, excellent photoelectric properties and high stability. Using the above-mentioned anthracene-based thermoexciton material as the organic light-emitting material of the light-emitting layer ink can make the light-emitting device have good luminous efficiency and performance stability. The chemical structure of the above-mentioned anthracene-based thermoexciton material is as follows:

[0063]

[0064] In some embodiments, the viscosity of the light-emitting layer ink at 20° C. is 0.1 cP-20 cP, and the surface tension of the light-emitting layer ink is 20 mN / m-50 mN / m.

[0065] In some embodiments, the second aspect of the present invention provides a method for preparing a light-emitting device, the method comprising the following steps S100 to S300:

[0066] Step S100: providing a first electrode;

[0067] Step S200: depositing light-emitting layer ink on the first electrode to form a light-emitting layer;

[0068] Step S300: depositing a second electrode on the light-emitting layer to obtain a light-emitting device.

[0069] The luminous layer ink adopts the ink of the first aspect of the present invention.

[0070] In some of the embodiments, a light-emitting layer ink is deposited on the first electrode by a solution method, and the light-emitting layer is formed after annealing; wherein the solution method includes inkjet printing, spin coating and pad printing; the annealing temperature is 100°C~150°C, and the annealing time is 5min~30min.

[0071] See also Figure 1In some embodiments, the third aspect of the present invention provides a light-emitting device 10, which includes a first electrode 11, a light-emitting layer 14, and a second electrode 17 stacked in sequence. Among them, the material forming the light-emitting layer 14 includes the light-emitting layer ink of the first aspect of the present invention. By using the light-emitting layer ink of the first aspect of the present invention to form the light-emitting layer 14 of the light-emitting device 10, the light-emitting layer ink has good spreadability and film-forming properties, can effectively improve the luminous efficiency and performance stability of the light-emitting device 10, and improve the preparation efficiency of the light-emitting device 10. It can be understood that the light-emitting layer ink can be applied on the substrate by inkjet printing or solution spin coating, and the light-emitting layer 14 is formed after curing.

[0072] In some embodiments, the thickness of the light emitting layer 14 in the light emitting device 10 is 10 nm to 50 nm. By controlling the thickness of the light emitting layer 14 within the above range, the light emitting device 10 can have good luminous efficiency. It is understood that the thickness of the light emitting layer 14 can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, and any value within the range formed by any two of the above values.

[0073] In some embodiments, the material of the first electrode 11 in the light-emitting device 10 includes one or more of a metal, a carbon material and a metal oxide, the metal includes one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb and Mg; the carbon material includes one or more of graphite, carbon nanotubes, graphene and carbon fiber; the metal oxide includes a doped or undoped metal oxide, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO, or includes a composite electrode in which a metal is sandwiched between doped or undoped transparent metal oxides, and the composite electrode includes one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2 and TiO2 / Al / TiO2.

[0074] In some embodiments, the first electrode 11 is any one of a glass substrate composited with an indium tin oxide (ITO) film, a transparent polymer substrate composited with an indium tin oxide film, and a metal substrate composited with an indium tin oxide film. The above-mentioned first electrode 11 has a higher work function, which can enable the light-emitting device 10 to have a higher hole injection efficiency. Among them, the transparent polymer substrate can be polyaniline. In a specific example, the first electrode 11 is ITO conductive glass.

[0075] In some embodiments, the material of the second electrode 17 includes one or more of metals, carbon materials and metal oxides, the metal includes one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb and Mg; the carbon material includes one or more of graphite, carbon nanotubes, graphene and carbon fiber; the metal oxide includes doped or undoped metal oxides, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO, or includes a composite electrode in which a metal is sandwiched between doped or undoped transparent metal oxides, and the composite electrode includes one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2 and TiO2 / Al / TiO2.

[0076] In some embodiments, the second electrode 17 includes any one of a silver electrode and an aluminum electrode. Using the above material as the second electrode 17 has a lower work function, which enables the light emitting device 10 to have a higher electron injection efficiency and better light emitting efficiency.

[0077] In some embodiments, the light-emitting device 10 further includes a hole injection layer 12, which is disposed between the first electrode 11 and the light-emitting layer 14. The material of the hole injection layer 12 can be one or more of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-Nphenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tin compounds, doped graphene, undoped graphene, and C60.

[0078] In some embodiments, the light-emitting device 10 further includes a hole transport layer 13, which is disposed between the hole injection layer 12 and the light-emitting layer 14. The material of the hole transport layer 13 can be one or more of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-Nphenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tin compounds, doped graphene, undoped graphene, and C60.

[0079] In some embodiments, the light emitting device 10 further includes an electron transport layer 15, which is disposed between the light emitting layer 14 and the second electrode 17. The material of the electron transport layer 15 may be an inorganic material and / or an organic material, the inorganic material including one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate, the doped element including one or more of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the organic material including 8-hydroxyquinoline aluminum, diphenyl [4- (triphenylsilyl) phenyl] phosphine oxide (TSPO1) , 1,3,5-tri(3-pyridyl-3-phenyl)benzene (TmPyPB), 2-(4'-tert-butylphenyl)-5-(4'-biphenyl)-1,3,4-oxadiazole (PBD), 8-hydroxyquinoline beryllium (Beq2), 1,2,4-triazole derivatives (TAZ), 2,7-bis(diphenylphosphinyl)-9,9'-spirobi[fluorene] (SPPO13), 1,3,5-tri(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBI), 4,6-bis(3,5-di(3-pyridyl)phenyl)-2-methylpyrimidine (B3PYMPM) and 4,7-diphenyl-1,10-phenanthroline (Bphen).

[0080] In some embodiments, the light emitting device 10 further includes an electron injection layer 16, which is disposed between the electron transport layer 15 and the second electrode 17. The material of the electron injection layer 16 can be an inorganic material and / or an organic material, the inorganic material includes metallic lithium, lithium fluoride, magnesium fluoride, and one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate, the doped element includes one or more of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the organic material includes one or more of tantalum, ... The material includes one or more of 8-hydroxyquinoline aluminum, diphenyl [4- (triphenylsilyl) phenyl] phosphine oxide, 1,3,5-tri (3-pyridyl-3-phenyl) benzene, 2- (4'-tert-butylphenyl) -5- (4'-biphenyl) -1,3,4- oxadiazole, 8-hydroxyquinoline beryllium, 1,2,4-triazole derivatives, 2,7-bis (diphenylphosphinyl) -9,9'-spirobis [fluorene], 1,3,5-tri (1-phenyl-1H-benzimidazol-2-yl) benzene, 4,6-bis (3,5-di (3-pyridyl) phenyl) -2-methylpyrimidine and 4,7-diphenyl-1,10-phenanthroline.

[0081] The present invention will be further described below in conjunction with specific embodiments and comparative examples, but they should not be construed as limiting the scope of protection of the present invention.

[0082] Ink Example 1:

[0083] PAC is used as an organic light-emitting material, vinyl ethyl ether is used as a diluent, and ethylene glycol is used as a solvent; PAC and vinyl ethyl ether are dissolved in the solvent ethylene glycol at a mass ratio of 99:1 to form a light-emitting layer ink. The concentration of PAC in the light-emitting layer ink is 20 mg / mL.

[0084] Ink Example 2:

[0085] This embodiment is basically the same as ink embodiment 1, with the only difference being that the mass ratio of PAC to vinyl ethyl ether in the luminescent layer ink is 98:2.

[0086] Ink Example 3:

[0087] This embodiment is basically the same as ink embodiment 1, with the only difference being that the mass ratio of PAC to vinyl ethyl ether in the luminescent layer ink is 97:3.

[0088] Ink Example 4:

[0089] This embodiment is basically the same as ink embodiment 1, with the only difference being that the mass ratio of PAC to vinyl ethyl ether in the luminescent layer ink is 96:4.

[0090] Ink Example 5:

[0091] This embodiment is basically the same as ink embodiment 1, with the only difference being that vinyl acetate is used as a diluent in the luminescent layer ink.

[0092] Ink Example 6:

[0093] This embodiment is basically the same as ink embodiment 2, with the only difference being that vinyl acetate is used as a diluent in the luminescent layer ink.

[0094] Ink Example 7:

[0095] This embodiment is basically the same as ink embodiment 3, with the only difference being that vinyl acetate is used as a diluent in the luminescent layer ink.

[0096] Ink Example 8:

[0097] This embodiment is basically the same as ink embodiment 4, with the only difference being that vinyl acetate is used as a diluent in the luminescent layer ink.

[0098] Ink Example 9:

[0099] This embodiment is basically the same as ink embodiment 2, with the only difference being that methyl acrylate is used as a diluent in the luminescent layer ink.

[0100] Ink Example 10:

[0101] This embodiment is basically the same as ink embodiment 2, with the only difference being that n-butanol is used as a diluent in the luminescent layer ink.

[0102] Ink Example 11:

[0103] This embodiment is basically the same as ink embodiment 2, with the only difference being that benzyl alcohol is used as a diluent in the luminescent layer ink.

[0104] Ink Example 12:

[0105] This embodiment is basically the same as ink embodiment 2, with the only difference being that PABP is used as the luminescent material in the luminescent layer ink.

[0106] Ink Example 13:

[0107] This embodiment is basically the same as ink embodiment 2, with the only difference being that PATPA is used as the luminescent material in the luminescent layer ink.

[0108] Ink comparison example 1:

[0109] PAC is used as an organic light-emitting material and ethylene glycol is used as a solvent; PAC is dissolved in the solvent ethylene glycol to form a light-emitting layer ink. The concentration of PAC in the light-emitting layer ink is 20 mg / mL.

[0110] Device Example 1:

[0111] A glass substrate composited with a transparent conductive film ITO (i.e., ITO conductive glass) is used as the first electrode (the electrode is used as an anode), and the thickness of the first electrode is 50nm; PEDOT:PSS is deposited on the ITO by a solution method as a hole injection layer, and the thickness of the hole injection layer is 30nm; PVK is deposited on the hole injection layer by a solution method as a hole transport layer, and the thickness of the hole transport layer is 20nm;

[0112] Depositing OLED light-emitting layer ink on the hole transport layer by a solution method, and annealing at 150° C. for 10 minutes to form a light-emitting layer; the light-emitting layer ink adopts the light-emitting layer ink of ink embodiment 1; the thickness of the light-emitting layer is 35 nm;

[0113] SPPO13 is deposited on the light-emitting layer by evaporation as an electron transport layer, and the thickness of the electron transport layer is 30nm; Li is deposited on the electron transport layer by evaporation as an electron injection layer, and the thickness of the electron injection layer is 100nm; Al is deposited on the electron injection layer by evaporation as a mixed second electrode (this electrode serves as a cathode), and the thickness of the second electrode is 100nm. Thus, an OLED light-emitting device is formed.

[0114] Device Example 2:

[0115] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink embodiment 2.

[0116] Device Example 3:

[0117] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink embodiment 3.

[0118] Device Example 4:

[0119] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink embodiment 4.

[0120] Device Example 5:

[0121] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink embodiment 5.

[0122] Device Example 6:

[0123] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink embodiment 6.

[0124] Device Example 7:

[0125] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink embodiment 7.

[0126] Device Example 8:

[0127] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink embodiment 8.

[0128] Device Example 9:

[0129] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink embodiment 9.

[0130] Device Example 10:

[0131] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink embodiment 10.

[0132] Device Example 11:

[0133] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink embodiment 11.

[0134] Device Example 12:

[0135] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink embodiment 12.

[0136] Device Example 13:

[0137] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink embodiment 13.

[0138] Device Comparison Example 1:

[0139] This embodiment is basically the same as device embodiment 1, with the only difference being that the light-emitting layer ink uses the light-emitting layer ink of ink comparison example 1.

[0140] Performance testing method:

[0141] 1) Light-emitting device driving voltage test

[0142] The current density-brightness-voltage characteristic curve of the light-emitting device is plotted by using a Keithley 2450 digital source meter and an LS160 brightness meter, and the driving voltage V of the light-emitting device at a specific current density is obtained according to the current density-brightness-voltage characteristic curve.

[0143] Where, V@10mA / cm 2 It means that the light emitting device has a current density of 10mA / cm 2 The corresponding driving voltage.

[0144] 2) External quantum efficiency (EQE) test of light-emitting devices

[0145] The current density-brightness-voltage characteristic curve of the light-emitting device was plotted by Keithley 2450 digital source meter and LS160 brightness meter, and the EL spectrum of the light-emitting device was recorded by optical analyzer FLAME-S-VIS-NIR photometer. The external quantum efficiency EQE of the light-emitting device was directly calculated by the instrument based on the EL spectrum, brightness and current density.

[0146] Among them, EQE@10mA / cm 2 It means that the light emitting device has a current density of 10mA / cm 2 The external quantum efficiency EQE corresponding to the time. The value of the external quantum efficiency EQE reflects the luminous efficiency of the light-emitting device. The larger the EQE value, the higher the luminous efficiency of the light-emitting device.

[0147] 3) Light-emitting device stability test

[0148] The test environment is 25℃ and relative humidity is 60%. The light-emitting device is driven with a constant current of 2mA. The brightness change of the light-emitting device is tested using a silicon photonic system. The T 95 (h)@1000cd / m 2 .

[0149] Among them, T 95 (h)@1000cd / m 2 It means that the initial brightness of the light emitting device is 1000cd / m 2 When the brightness decays to 95% of the initial brightness (here is 950cd / m 2 ) is the time elapsed. 95 The time T reflects the stability of the light-emitting device. 95 The longer the time is, the better the stability of the light-emitting device is.

[0150] The performance of the light-emitting layer ink used in the above device embodiments and device comparative examples and the performance of the light-emitting device were tested, and the test results of each device embodiment and device comparative example are shown in Table 1. The external quantum efficiency-current density relationship curve of the light-emitting device of each device embodiment and device comparative example is shown in Table 1. Figure 2 shown.

[0151] Table 1

[0152]

[0153] By comparing the above device embodiments and device comparative example 1, it can be seen that the present invention can significantly improve the external quantum efficiency EQE value of the light-emitting device by using a specific diluent in the light-emitting layer ink, effectively improve the luminous efficiency of the light-emitting device; and can also make the T 95 The time is significantly extended, and the performance stability of the light-emitting device is improved.

[0154] By comparing device examples 1 to 4, it can be seen that when the diluent in the light-emitting layer ink is vinyl ethyl ether, the mass ratio of the organic light-emitting material to the diluent in the ink is controlled within the range of 97-98:2-3; the external quantum efficiency EQE and T of the light-emitting device can be further improved. 95 , which can make the light-emitting device have higher luminous efficiency and better performance stability.

[0155] By comparing device example 2 and device example 3, it can be seen that when the diluent in the light-emitting layer ink is vinyl ethyl ether, the mass ratio of the organic light-emitting material to the diluent in the ink is further controlled to 98:2, which can further improve the external quantum efficiency EQE and T of the light-emitting device. 95 , so that the light-emitting device has higher luminous efficiency and better performance stability.

[0156] By comparing device examples 5 to 8, it can be seen that when the diluent in the light-emitting layer ink is vinyl acetate, the mass ratio of the organic light-emitting material to the diluent in the ink is controlled within the range of 98-99:1-2; the external quantum efficiency EQE and T of the light-emitting device can be further improved. 95 , which can make the light-emitting device have higher luminous efficiency and better performance stability.

[0157] By comparing device example 5 and device example 6, it can be seen that when vinyl acetate is used as the diluent in the light-emitting layer ink, the mass ratio of the organic light-emitting material to the diluent in the ink is further controlled to 98:2, which can further improve the external quantum efficiency EQE and T of the light-emitting device. 95 , so that the light-emitting device has higher luminous efficiency and better performance stability.

[0158] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0159] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An ink, characterized in that: The ink comprises an organic light-emitting material, a diluent and a solvent, wherein the diluent comprises one or more of vinyl aliphatic ether, acrylic aliphatic ester, aliphatic alcohol, aromatic alcohol and fatty acid vinyl ester.

2. The ink according to claim 1, characterized in that The mass ratio of the organic light-emitting material to the diluent in the ink is 96-99:1-4; And / or, the concentration of the organic light-emitting material in the ink is 10 mg / mL to 30 mg / mL.

3. The ink according to claim 1, characterized in that The vinyl fatty ether includes a vinyl fatty ether having a carbon number of 2 to 6 in the fatty group; And / or, the aliphatic acrylate comprises an aliphatic acrylate having an aliphatic group with 1 to 10 carbon atoms; And / or, the fatty alcohol comprises a fatty alcohol having 2 to 4 carbon atoms; And / or, the aromatic alcohol comprises an aromatic alcohol having 6 to 12 carbon atoms; And / or, the fatty acid vinyl ester includes fatty acid vinyl ester in which the carbon number of the fatty acid is 2 to 24.

4. The ink according to claim 1, characterized in that The vinyl aliphatic ether includes one or more of vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether and vinyl cyclohexyl ether; And / or, the aliphatic acrylate includes one or more of isobutyl acrylate, butyl acrylate, isobornyl acrylate, methyl acrylate, ethyl acrylate and cyclohexyl acrylate; and / or, the fatty alcohol comprises one or more of isopropanol, n-butanol, anhydrous ethanol and propylene glycol; And / or, the aromatic alcohol includes one or more of benzyl alcohol, phenylethyl alcohol and phenylpropanol; and / or, the fatty acid vinyl ester comprises one or more of vinyl acetate, vinyl oleate and vinyl stearate; And / or, the solvent includes one or more of ethylene glycol, glycerol, ethyl benzoate, isopropyl benzoate, n-butyl lactate, o-dichlorobenzene, tetralin, mesitylene, methyl benzoate, toluene, xylene, chlorobenzene, chloroform, tetrahydrofuran, acetonitrile, dichloromethane, cyclohexylbenzene and tetralin.

5. The ink according to claim 4, characterized in that The diluent is vinyl ethyl ether, and the mass ratio of the organic light-emitting material to the diluent in the light-emitting layer ink is 97-98:2-3; Or the diluent is vinyl acetate, and the mass ratio of the organic light-emitting material to the diluent in the light-emitting layer ink is 98-99:1-2.

6. The ink according to any one of claims 1 to 5, characterized in that The organic light-emitting material includes anthracene-based thermal exciton material; Optionally, the anthracene-based thermoexciton material includes one or more of PABPP, mPAC, PAC, PAIDO, PABP and PATPA; and / or, the viscosity of the ink at 20° C. is 0.1 cP to 20 cP; And / or, the surface tension of the ink is 20mN / m~50mN / m.

7. A method for preparing a light emitting device, characterized in that: The preparation method comprises the following steps: providing a first electrode; Depositing a light-emitting layer ink on the first electrode to form a light-emitting layer; Depositing a second electrode on the light-emitting layer to obtain a light-emitting device; Wherein, the light-emitting layer ink is selected from the ink described in any one of claims 1 to 6.

8. The preparation method according to claim 7, characterized in that: The step of depositing light-emitting layer ink on the first electrode to form a light-emitting layer comprises the following steps: Depositing the light-emitting layer ink on the first electrode by a solution method, and forming the light-emitting layer after annealing; Optionally, the solution method includes inkjet printing, spin coating and pad printing; Optionally, the annealing temperature is 100° C. to 150° C., and the annealing time is 5 min to 30 min.

9. A light-emitting device, comprising a first electrode, a light-emitting layer and a second electrode stacked in sequence, characterized in that: The material forming the light-emitting layer includes the ink as claimed in any one of claims 1 to 6; Or, the light-emitting device is prepared by the preparation method according to any one of claims 7 to 8.

10. The light emitting device according to claim 9, characterized in that: The thickness of the light-emitting layer is 10nm~50nm; And / or, the materials of the first electrode and the second electrode each independently include one or more of a metal, a carbon material and a metal oxide, the metal includes one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb and Mg; the carbon material includes one or more of graphite, carbon nanotubes, graphene and carbon fiber; the metal oxide includes a doped or undoped metal oxide, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO, or includes a composite electrode in which a metal is sandwiched between doped or undoped transparent metal oxides, and the composite electrode includes one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2 and TiO2 / Al / TiO2; And / or, the light-emitting device further comprises a hole injection layer and / or a hole transport layer, the hole injection layer and the hole transport layer are arranged between the first electrode and the light-emitting layer, and the materials of the hole injection layer and the hole transport layer independently comprise one or more of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-Nphenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tinides, doped graphene, undoped graphene and C60; And / or, the light-emitting device further comprises an electron transport layer, the electron transport layer is arranged between the light-emitting layer and the second electrode, the material of the electron transport layer comprises an inorganic material and / or an organic material, the inorganic material comprises one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate, and the doped elements comprise aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, One or more of cerium and gadolinium; the organic material includes one or more of 8-hydroxyquinoline aluminum, diphenyl [4- (triphenylsilyl) phenyl] phosphine oxide, 1,3,5-tri (3-pyridyl-3-phenyl) benzene, 2- (4'-tert-butylphenyl) -5- (4'-biphenyl) -1,3,4- oxadiazole, 8-hydroxyquinoline beryllium, 1,2,4-triazole derivatives, 2,7-bis (diphenyl phosphinyl) -9,9'-spirobis [fluorene], 1,3,5-tri (1-phenyl-1H-benzimidazol-2-yl) benzene, 4,6-bis (3,5-di (3-pyridyl) phenyl) -2-methylpyrimidine and 4,7-diphenyl -1,10-phenanthroline; And / or, the light emitting device further comprises an electron injection layer, the electron injection layer is arranged between the light emitting layer and the second electrode, the material of the electron injection layer comprises an inorganic material and / or an organic material, the inorganic material comprises metallic lithium, lithium fluoride, magnesium fluoride, and one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, nickel oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate, and the doped elements comprise aluminum, magnesium, lithium, manganese, yttrium, lanthanum , copper, nickel, zirconium, cerium, and gadolinium; the organic material includes one or more of 8-hydroxyquinoline aluminum, diphenyl [4- (triphenylsilyl) phenyl] phosphine oxide, 1,3,5-tri (3-pyridyl-3-phenyl) benzene, 2- (4'-tert-butylphenyl) -5- (4'-biphenyl) -1,3,4- oxadiazole, 8-hydroxyquinoline beryllium, 1,2,4-triazole derivatives, 2,7-bis (diphenyl phosphinyl) -9,9'-spirobis [fluorene], 1,3,5-tri (1-phenyl-1H-benzimidazol-2-yl) benzene, 4,6-bis (3,5-di (3-pyridyl) phenyl) -2-methylpyrimidine and 4,7-diphenyl -1,10-phenanthroline.

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