CN-122002982-A - Micro-LED display device based on double-additive modified quantum dot color conversion layer and preparation method thereof

CN122002982ACN 122002982 ACN122002982 ACN 122002982ACN-122002982-A

Abstract

The invention discloses a Micro-LED display device based on a double-additive modified quantum dot color conversion layer and a preparation method thereof, and relates to the technical field of semiconductor display. The method comprises the steps of preparing a Micro-LED array, forming a groove array with isolated pixels above a light-emitting unit through an etching process, preparing a modified perovskite quantum dot solution, simultaneously introducing crown ether and citric acid into a quantum dot precursor or the solution to serve as a dual-function additive, respectively depositing red, green and blue modified quantum dot solutions into grooves corresponding to the Micro-LED array, and drying to form a color conversion layer. The invention utilizes citric acid to regulate the crystal growth kinetics of the quantum dot, promotes the uniform size and the oriented growth of crystal grains, and simultaneously utilizes crown ether to carry out defect passivation on the strong complexation of non-coordinated cations on the surface. The synergistic effect of the two obviously reduces the non-radiative recombination center of the quantum dot, greatly improves the photoluminescence quantum yield and the environmental stability of the color conversion layer, and effectively solves the problems of light crosstalk and low efficiency in Micro-LED full-color conversion.

Inventors

MA JIANHAO
SHEN ZHONGWEN
YOU TUANRUI
Su Zhongfang
HU CHENHAO
ZHANG YUJIE
PAN JIANGYONG
XU JINFENG
HE NAILONG
WANG LIQIAN
ZHANG YUNING
SU ZHICHENG
LV JUNPENG

Assignees

新型显示与视觉感知石城实验室
南京信息工程大学

Dates

Publication Date: 20260508
Application Date: 20260127

Claims (10)

1. The preparation method of the Micro-LED display device based on the double-additive modified quantum dot color conversion layer is characterized by comprising the following steps of: S1, cleaning and drying a glass substrate, and then carrying out ultraviolet ozone surface treatment; S2, preparing a Micro-LED light-emitting array on the processed glass substrate, and forming a pixel isolation structure between adjacent light-emitting units to define a pixel deposition cavity for depositing a color conversion layer; s3, respectively preparing red, green and blue perovskite quantum dot solutions, simultaneously adding crown ether and citric acid into each solution as modification additives, and uniformly mixing to obtain modified red, green and blue three-color quantum dot solutions; s4, selectively depositing the modified red, green and blue quantum dot solutions prepared in the step S3 into the pixel deposition cavities with the corresponding colors formed in the step S2 respectively; S5, after the quantum dot solution to be deposited in the pixel deposition cavity is dried, forming a quantum dot color conversion layer, and then packaging the quantum dot color conversion layer; The formed quantum dot color conversion layer is composed of a mixed material containing perovskite quantum dots, crown ether and citric acid, wherein the crown ether is distributed on the surface of quantum dot crystals, and the citric acid is distributed in quantum dot crystal boundaries or crystal networks.
2. The method according to claim 1, wherein the crown ether is at least one of 18-crown-6 or dibenzo-18-crown-6, and the crown ether is present in the quantum dot solution at a concentration of 1mg/mL to 8mg/mL.
3. The preparation method according to claim 1, wherein the citric acid is added in an amount of 1wt% to 15wt% of the total mass of the quantum dot precursor.
4. The method of claim 1, wherein the perovskite quantum dots are one or more of an all-inorganic perovskite CsPbX 3 , an organic-inorganic hybrid perovskite MAPbX 3 、FAPbX 3 , a lead-free perovskite CsCu 2 I 3 , or a manganese-ion doped perovskite material, wherein X is at least one of Cl, br, I.
5. The method of claim 1, wherein the pixel isolation structure formed in step S2 includes a passivation material filled in a light emitting cell gap and a metal reflective wall disposed in the passivation material.
6. The method according to claim 1, wherein the Micro-LED light emitting unit has a center wavelength of 440nm to 480nm blue light or 365nm to 400nm ultraviolet light.
7. The method of claim 1, wherein in step S5, the encapsulation process employs an organic/inorganic stacked structure including an atomic layer deposited aluminum oxide film and a polymer buffer layer alternately deposited, the atomic layer deposited aluminum oxide film having a thickness of 5nm to 50nm.
8. A Micro-LED display device based on a dual additive modified quantum dot color conversion layer, prepared by the method of any one of claims 1-7, comprising: A glass substrate; a Micro-LED light emitting array arranged on the glass substrate; The pixel isolation structure is positioned between adjacent light emitting units of the Micro-LED light emitting array and defines a pixel deposition cavity together with the light emitting array; the quantum dot color conversion layer is arranged in the pixel deposition cavity; The packaging layer is covered on the quantum dot color conversion layer and the pixel isolation structure; The quantum dot color conversion layer is a perovskite quantum dot composite material layer containing crown ether and citric acid, the crown ether is distributed on the surface of a quantum dot crystal, and the citric acid is distributed in a quantum dot grain boundary or a crystal network.
9. The Micro-LED display device of claim 8, wherein the crown ether is at least one of 18-crown-6 or dibenzo-18-crown-6, the relative content of crown ether in the perovskite quantum dot composite layer corresponds to a concentration of 1mg/mL to 8mg/mL in the quantum dot solution during the preparation thereof, and the relative content of citric acid corresponds to a content of 1wt% to 15wt% of the total mass of the perovskite quantum dot precursor during the preparation thereof.
10. The Micro-LED display device of claim 8, wherein the perovskite quantum dots are one or more of all-inorganic perovskite CsPbX 3 , organic-inorganic hybrid perovskite MAPbX 3 、FAPbX 3 , lead-free perovskite CsCu 2 I 3 , or perovskite material doped with manganese ions, wherein X is at least one of Cl, br, I, and the Micro-LED light emitting unit has a blue light with a center wavelength of 440nm-480nm or an ultraviolet light with a center wavelength of 365nm-400 nm.

Description

Micro-LED display device based on double-additive modified quantum dot color conversion layer and preparation method thereof Technical Field The invention belongs to the technical field of semiconductor display, and particularly relates to a Micro-LED display device based on a perovskite quantum dot color conversion layer. More specifically, the invention discloses a preparation method and application thereof, wherein crown ether and citric acid are introduced into a quantum dot solution to serve as synergistic modification additives, so that the luminous efficiency and stability of a quantum dot color conversion layer are remarkably improved. Background The Micro-LED display technology is regarded as a powerful competitor of the next generation display technology by virtue of the advantages of high brightness, high contrast, high integration, quick response, low power consumption and the like, and has wide application prospect in the fields of AR/VR, intelligent watch, large-size display and the like. However, achieving efficient and reliable full color is one of the key challenges facing commercialization of Micro-LED technology. The main current full-color scheme mainly depends on a quantum dot color conversion technology, namely, a blue or ultraviolet Micro-LED chip is utilized to excite a quantum dot material deposited on the quantum dot material to generate red light and green light, and three primary colors are displayed by combining unconverted blue light. Perovskite quantum dots are the most ideal color conversion materials due to their excellent characteristics of high photoluminescence quantum yield, narrow emission spectrum, tunable band gap, and the like. However, perovskite quantum dots still present the following major technical bottlenecks when applied to Micro-LED display devices: 1. Perovskite materials essentially have a large number of surface defects and grain boundary defects, the defect points are non-radiative recombination centers of electrons and holes, the luminous efficiency of quantum dots is lower than a theoretical value, and the quantum dots are extremely easy to decompose under the actions of illumination, humidity and thermal stress, so that the service life of the device is short. 2. In preparing the color conversion layer, the film formation process of the quantum dot solution is difficult to control accurately, whether by spin coating, ink jet printing, or other deposition methods. The crystal grain size of the quantum dot is easy to be uneven, the crystal grain boundary is loose, and a porous or rough film is formed, so that the luminous efficiency is affected, a channel is provided for invasion of moisture and oxygen, and the failure of the device is further accelerated. 3. In the prior art, the performance of quantum dots is often improved by introducing various organic ligands (such as oleic acid, oleylamine) or passivating agents. However, these single additives often only address one aspect of the problem of focusing on either surface defect passivation or crystal growth regulation, and it is difficult to achieve an overall improvement in quantum dot performance. Therefore, a preparation method capable of simultaneously optimizing nucleation and growth processes of perovskite quantum dot crystals and effectively passivating surface defects is urgently needed in the industry so as to obtain a color conversion layer with high photoluminescence quantum yield, high stability and high density, and further greatly improve the photoelectric performance and reliability of a Micro-LED display device. Disclosure of Invention Technical problems: the invention aims to solve the technical problems of high surface defect density, serious non-radiative recombination, uncontrollable film forming crystal quality and the like faced by the perovskite quantum dot color conversion layer in the existing Micro-LED full-color display technology. The invention provides a Micro-LED display device, which is characterized in that a double additive modified quantum dot color conversion layer is introduced. The color conversion layer is prepared by cooperatively introducing crown ether and citric acid into a perovskite quantum dot material. The technical scheme is as follows: the aim of the invention can be achieved by the following technical scheme: A preparation method of a Micro-LED display device based on a double-additive modified quantum dot color conversion layer comprises the following steps: S1, cleaning and drying a glass substrate, and then carrying out ultraviolet ozone surface treatment; S2, preparing a Micro-LED light-emitting array on the processed glass substrate, and forming a pixel isolation structure between adjacent light-emitting units to define a pixel deposition cavity for depositing a color conversion layer; s3, respectively preparing red, green and blue perovskite quantum dot solutions, simultaneously adding crown ether and citric acid into each solution as modification