CN-118344773-B - Quantum dot ink and electroluminescent device

CN118344773BCN 118344773 BCN118344773 BCN 118344773BCN-118344773-B

Abstract

The invention relates to the technical field of ink-jet printing and discloses quantum dot ink and an electroluminescent device, wherein the quantum dot ink comprises quantum dots and a mixed polar solvent, the quantum dots comprise quantum dot bodies and organic chain segments connected to the surfaces of the quantum dot bodies, the organic chain segments are linked with functional groups which are soluble in the polar solvent, and the mixed polar solvent comprises a plurality of polar solvents. The invention connects the surface of the quantum dot body with the functional group which can be dissolved in the polar solvent, so that the quantum dot can be dissolved in the polar solvent, when the ink is printed on the TFB layer, the ink is similar to the TFB layer, the interface compatibility of the quantum dot luminous layer formed by solidifying the ink and the TFB layer is high, the film surface of the electroluminescent device is prepared to emit light uniformly, and zinc halide is added into the ink as an auxiliary agent, so that the electrical property of the luminous layer formed by the ink is improved, and the luminous brightness of the electroluminescent device is improved.

Inventors

WU JINGFEI
MA BO
WANG YUNJUN

Assignees

苏州星烁纳米科技有限公司

Dates

Publication Date: 20260508
Application Date: 20231121

Claims (8)

1. The quantum dot ink is characterized by comprising quantum dots, an auxiliary agent and a mixed polar solvent, wherein the quantum dots comprise quantum dot bodies and organic chain segments connected to the surfaces of the quantum dot bodies, the organic chain segments are linked with functional groups which are soluble in the polar solvent, the mixed polar solvent comprises a plurality of polar solvents, the organic chain segments are at least one of pentaerythritol tetra (3-mercaptopropionate), pentaerythritol tetra (3-mercaptobutyrate) and tris [2- (3-mercaptopropionyloxy) ethyl ] isocyanurate, the functional groups which are soluble in the polar solvent comprise at least one of ester groups, ether groups, hydroxyl groups, amino groups and amide groups, the auxiliary agent comprises a zinc halide compound, the zinc halide is at least one of zinc chloride, zinc bromide and zinc iodide, and the mass ratio of the zinc halide in the quantum dot ink is 1% -10%.
2. The quantum dot ink of claim 1, wherein the quantum dot is obtained by reacting the quantum dot body with an organic compound comprising a polar solvent-soluble functional group dispersed in a solvent.
3. The quantum dot ink of claim 2, wherein when the polar solvent-soluble functional group comprises an ester group, the organic compound comprises one of ethyl acetate, methyl formate, glycerol stearate; When the polar solvent-soluble functional group includes an ether group, the organic compound includes at least one of ethylene glycol butyl ether, dipropylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol butyl ether; when the polar solvent-soluble functional group includes a hydroxyl group, the organic compound includes one of methanol, ethanol, ethylene glycol, glycerol, n-butanol, inositol, benzyl alcohol, phenol, cresol, aminophenol, nitrophenol, naphthol, chlorophenol; When the polar solvent-soluble functional group includes an amine group, the organic compound includes one of dimethylamine, diethylamine, dipropylamine, dibutylamine, N-ethylmethylamine, N-methyl N-propylamine; when the polar solvent-soluble functional group includes an amide group, the organic compound includes at least one of formamide, acetamide, propionamide, butyramide, or isobutyramide.
4. The quantum dot ink of claim 2, wherein the solvent that disperses the quantum dot bulk and the organic compound comprises at least one of xylene, toluene, trimethylbenzene.
5. The quantum dot ink of claim 1, wherein the mixed polar solvent comprises 3, 5-trimethyl-1-hexanol, tripropylene glycol butyl ether, n-decanol, lauric methacrylate, and 4-t-butylcyclohexyl acetate.
6. The quantum dot ink according to claim 5, wherein in the quantum dot ink, the mass ratio of the quantum dot is 2% -3%, the mass ratio of the 3, 5-trimethyl-1-hexanol is 30% -32%, the mass ratio of the tripropylene glycol butyl ether is 15% -17%, the mass ratio of the n-sunflower alcohol is 11% -13%, the mass ratio of the lauric acid methacrylate is 5% -7%, and the mass ratio of the acetic acid 4-tert-butylcyclohexyl ester is 31% -33%.
7. The quantum dot ink of claim 1, wherein the quantum dot is selected from blue cadmium-free and lead-free quantum dots.
8. An electroluminescent device comprising a light emitting layer prepared from the quantum dot ink of any one of claims 1-7.

Description

Quantum dot ink and electroluminescent device Technical Field The invention belongs to the technical field of ink-jet printing, and particularly relates to quantum dot ink and an electroluminescent device. Background The quantum dots (also called semiconductor nanocrystals) are novel semiconductor nanomaterials with the size of 1-10nm. They have unique Photoluminescence (PL) and Electroluminescent (EL) properties due to quantum size effects and dielectric confinement effects. Compared with the traditional organic fluorescent dye, the quantum dot has the excellent optical characteristics of high quantum yield, high photochemical stability, difficult photolysis, wide excitation, narrow emission, high color purity, adjustable luminescent color by controlling the size of luminescent nano particles and the like, and has wide application prospect in the technical field of display, wherein the quantum dot color film is one of the application modes with the highest current attention, and becomes a research hot spot. At present, a quantum dot color film is generally prepared by adopting an ink-jet printing process, and the technical advantage of the ink-jet printing process is that the dripping position and the volume of the quantum dot ink can be controlled, so that the film can be printed. The existing quantum dot ink is prepared by dispersing quantum dots in a nonpolar solvent, and when an electroluminescent device is manufactured, the quantum dot ink is printed on a TFB layer (hole transport layer) in an inkjet mode, and the TFB layer is formed by spin-coating polyaniline substances containing polarity, so that after the quantum dot ink is printed on the TFB layer to form a luminescent layer, an interface effect exists at the interface between the TFB layer and the luminescent layer, and the film surface of the device is uneven in light emission. In view of this, there is a need to develop a new quantum dot ink that is compatible with TFB layers formed from polar polyaniline-containing materials. Disclosure of Invention Accordingly, the present invention is directed to a quantum dot ink and an electroluminescent device, which can ensure uniform light emission on the surface of the electroluminescent device formed by the quantum dot ink. According to a first aspect of the invention, a quantum dot ink is provided, which comprises quantum dots and a mixed polar solvent, wherein the quantum dots comprise quantum dot bodies and organic chain segments connected to the surfaces of the quantum dot bodies, the organic chain segments are linked with functional groups which are soluble in the polar solvent, and the mixed polar solvent comprises a plurality of polar solvents. As a preferred embodiment of the quantum dot ink, the quantum dot ink further comprises an auxiliary agent, wherein the auxiliary agent comprises a zinc halide compound; Preferably, the zinc halide is selected from at least one of zinc chloride, zinc bromide and zinc iodide; preferably, the zinc halide accounts for 1-10% of the mass of the quantum dot ink. As a preferable embodiment of the quantum dot ink, the organic segment is at least one selected from pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutyrate), and tris [2- (3-mercaptopropionyloxy) ethyl ] isocyanurate; preferably, the polar solvent-soluble functional group includes at least one of an ester group, an ether group, a hydroxyl group, an amine group, and an amide group. As a preferable embodiment of the quantum dot ink described above, the quantum dot is obtained by reacting the quantum dot body with an organic compound containing a functional group soluble in a polar solvent dispersed in a solvent. As a preferable aspect of the above quantum dot ink, when the polar solvent-soluble functional group includes an ester group, the organic compound includes one of ethyl acetate, methyl formate, and glyceryl stearate; When the polar solvent-soluble functional group includes an ether group, the organic compound includes at least one of ethylene glycol butyl ether, dipropylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol butyl ether; when the polar solvent-soluble functional group includes a hydroxyl group, the organic compound includes one of methanol, ethanol, ethylene glycol, glycerol, n-butanol, inositol, benzyl alcohol, phenol, cresol, aminophenol, nitrophenol, naphthol, chlorophenol; When the polar solvent-soluble functional group includes an amine group, the organic compound includes one of dimethylamine, diethylamine, dipropylamine, dibutylamine, N-ethylmethylamine, N-methyl N-propylamine; when the polar solvent-soluble functional group includes an amide group, the organic compound includes at least one of formamide, acetamide, propionamide, butyramide, or isobutyramide. As a preferable mode of the quantum dot ink, the solvent for dispersing the quantum dot body and the organic compound includes at least one of xylene, tolue