CN-122003003-A - Full-color Micro-LED chip based on bimolecular passivation perovskite quantum dots and preparation method thereof

CN122003003ACN 122003003 ACN122003003 ACN 122003003ACN-122003003-A

Abstract

The invention discloses a full-color Micro-LED chip based on double-molecule passivated perovskite quantum dots and a preparation method thereof. The chip comprises a blue light Micro-LED array substrate and a perovskite quantum dot color conversion layer arranged on the light emitting side of the blue light Micro-LED array substrate, wherein the color conversion layer comprises green light and red light perovskite quantum dot pixels which are passivated by the cooperation of organic large cations and short-chain ammonium bromide double ligands and are distributed in a patterning manner corresponding to blue light pixels. The key of the preparation method is to adopt a layered micropore filling and atomic layer deposition in-situ packaging process. According to the scheme, the luminous efficiency and the stability of the quantum dot are cooperatively improved through bimolecular passivation, a flip-chip structure, pixel-level microcavity filling and multilayer packaging are combined, and finally the full-color Micro-LED chip with high performance and long service life is prepared, and the full-color Micro-LED chip has a wide application prospect in the novel display field.

Inventors

MA JIANHAO
SHEN ZHONGWEN
YOU TUANRUI
Su Zhongfang
HU CHENHAO
PAN JIANGYONG
HE NAILONG
ZHANG YUJIE
BAI ZHIWEI
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. Full-color Micro-LED chip based on bimolecular passivation perovskite quantum dot, characterized by comprising: The blue light Micro-LED array substrate and the perovskite quantum dot color conversion layer arranged on the light emitting side of the blue light Micro-LED array substrate; The perovskite quantum dot color conversion layer comprises green light perovskite quantum dot pixels and red light perovskite quantum dot pixels which are arranged corresponding to the blue light Micro-LED array pixels, and organic large cations and short-chain ammonium bromide are adopted as double ligands for the perovskite quantum dots to carry out synergistic passivation.
2. The full-color Micro-LED chip based on the double-molecule passivated perovskite quantum dots according to claim 1, wherein the blue light Micro-LED array substrate is of a flip-chip structure and comprises a sapphire substrate, a u-GaN buffer layer, an electron injection layer, a multi-quantum well active region and a hole injection layer from bottom to top, and is bonded with a driving circuit substrate through a metal bump array, and an insulating material with the light transmittance of more than 70% in a wave band of 450nm-470nm is filled in a gap of the metal bump array.
3. The full-color Micro-LED chip based on the double-molecule passivated perovskite quantum dot according to claim 1, wherein the organic macro cation is one of 2-phenylethylammonium bromide, 4-fluorophenylethyl ammonium bromide, 3-fluorophenylethyl ammonium bromide and 2-fluorophenylethyl ammonium bromide, and the short-chain ammonium bromide is one of ethyl ammonium bromide, propyl ammonium bromide and butyl ammonium bromide.
4. The full-color Micro-LED chip based on the double-molecule passivated perovskite quantum dots according to claim 3, wherein the organic macro cations and short-chain ammonium bromide ligands are cooperatively combined on the surface of the perovskite quantum dots, wherein the lead ion concentration is 0.1 mol/L-0.2 mol/L, the addition amount of the organic macro cations is 0.03 mol/L-0.18 mol/L, and the addition amount of the short-chain ammonium bromide is 0.03 mol/L-0.18 mol/L based on quantum dot synthesis precursors.
5. The full-color Micro-LED chip based on double-molecule passivated perovskite quantum dots according to claim 1, wherein the pixel size of the perovskite quantum dot color conversion layer is 2 μm to 50 μm, and the pixel size is in one-to-one correspondence with the pixel of the lower Fang Languang Micro-LED array.
6. The full-color Micro-LED chip based on the double-molecule passivated perovskite quantum dots according to claim 1, wherein the blue light emission peak wavelength of the blue light Micro-LED array substrate is 450nm to 470nm, and the overlapping degree of the light emission spectrum and the absorption spectrum of the perovskite quantum dots is more than 70%.
7. The full-color Micro-LED chip based on double-molecule passivated perovskite quantum dots according to claim 1, wherein the emission wavelength of the green perovskite quantum dot pixel is 520nm-540nm, and the emission wavelength of the red perovskite quantum dot pixel is 620nm-640nm.
8. A preparation method for the full-color Micro-LED chip as claimed in any one of claims 1-7 is characterized by comprising the following steps of S1, providing a blue light Micro-LED array substrate, and preparing a pixel isolation structure on a light-emitting surface of the blue light Micro-LED array substrate, wherein negative photoresist is coated on the substrate in a spinning manner, and a patterned pixel isolation wall is formed through a photoetching process, so that a green light pixel microcavity and a red light pixel microcavity which are isolated from each other are defined; s2, preparing a bicolor quantum dot functional material, namely respectively synthesizing green light and red light perovskite quantum dots which are passivated by the synergistic effect of organic large cations and short-chain ammonium bromide, mixing the quantum dots after purification with optical cement in proportion, and stirring to form homogeneous green light quantum dot gel and red light quantum dot gel; S3, layering filling and in-situ packaging the color conversion layer: S31, filling the green light quantum dot gel into the green light pixel microcavity defined in the step S1, and depositing a first layer of aluminum oxide packaging film on the surface of the green light quantum dot layer by adopting an atomic layer deposition process after flattening the surface by blade coating and polishing; S32, spin-coating negative photoresist on the packaged green pixel area again and performing photoetching to define a red light pixel microcavity; S33, filling the red light quantum dot gel into the red light pixel microcavity defined in the step S32, carrying out blade coating and polishing to planarize the surface, and depositing a second layer of aluminum oxide packaging film on the surface of the red light quantum dot layer by adopting an atomic layer deposition process, thereby forming a complete bicolor perovskite quantum dot color conversion unit; S4, packaging the whole surface, namely depositing a silicon nitride packaging layer on the surface of the color conversion unit prepared in the step S3 through a chemical vapor deposition process; and S5, integrating a driving circuit, namely bonding the blue light Micro-LED array substrate integrated with the color conversion unit with the driving circuit substrate through a metal bump array by adopting a flip-chip bonding process, and filling high-transmittance insulating materials in gaps of bonding bumps to finish chip preparation.
9. The method of claim 8, wherein the negative photoresist in steps S1 and S32 is SU8 series photoresist, and the size of the pixel microcavity is 2 μm to 50 μm.
10. The method of claim 8, wherein the mixing mass ratio of the quantum dots to the optical cement in step S2 is (4-6): 1.

Description

Full-color Micro-LED chip based on bimolecular passivation perovskite quantum dots and preparation method thereof Technical Field The invention belongs to the technical field of semiconductors, and particularly relates to a full-color Micro-LED chip based on double-molecule passivation perovskite quantum dots and a preparation method thereof. Background Micro light emitting diode (Micro-LED) display technology is recognized as a core direction of next generation display technology due to its excellent performance in terms of brightness, efficiency, response speed, contrast, service life, etc., and has a wide prospect in the fields of Augmented Reality (AR), virtual Reality (VR), ultra-high definition display, etc. However, realizing full color is a key technical problem that must be overcome in the industrialization of Micro-LEDs. The traditional RGB three-color chip direct bonding scheme is faced with the serious challenges of extremely complex process, extremely high alignment precision requirement, high cost and low yield because of the need of carrying out three times of 'mass transfer' on the red, green and blue three-color micron-sized chips. In this context, the technological path of "blue light Micro-LED array+quantum dot color conversion layer" has been developed and is widely considered as one of the optimal schemes for realizing full-color Micro-LED display. According to the scheme, only a single blue light Micro-LED array is needed to be prepared and transferred, and part of blue light is efficiently converted into red light and green light through a photoluminescence effect through a precisely patterned quantum dot layer above the single blue light Micro-LED array, so that full-color display is realized in a mixed mode. The method skillfully avoids the difficult problem of multicolor massive transfer and has the remarkable advantages of low cost, simple process and high integration level. Among the numerous quantum dot materials, perovskite quantum dots (perovskie QDs) are considered as ideal candidate materials for color conversion layers due to their outstanding characteristics of high luminescent color purity (narrow half-width), precisely controllable luminescent color (adjustable band gap), relatively low manufacturing cost, and the like. However, the inherent ionic crystal properties and lower enthalpy of formation of this material result in its extreme sensitivity to environmental moisture, oxygen, heat and light, and serious stability deficiencies. This bottleneck not only causes rapid degradation of the quantum dots during storage and operation, and degradation of the light-emitting efficiency (PLQY), but also makes it difficult to withstand the process conditions of subsequent device processing (e.g., photolithography, coating, etc.). Therefore, it is important to find a simple and efficient synthesis method and to improve the stability of perovskite quantum dots. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a full-color Micro-LED chip based on double-molecule passivation perovskite quantum dots and a preparation method thereof, so as to solve the technical problems of low luminous efficiency and poor environmental stability of the perovskite quantum dots in Micro-LED color conversion application. The aim of the invention can be achieved by the following technical scheme: A full-color Micro-LED chip based on bi-molecular passivated perovskite quantum dots, comprising: The blue light Micro-LED array substrate and the perovskite quantum dot color conversion layer arranged on the light emitting side of the blue light Micro-LED array substrate; The perovskite quantum dot color conversion layer comprises green light perovskite quantum dot pixels and red light perovskite quantum dot pixels which are arranged corresponding to the blue light Micro-LED array pixels, and organic large cations and short-chain ammonium bromide are adopted as double ligands for the perovskite quantum dots to carry out synergistic passivation. Furthermore, the blue light Micro-LED array substrate is of a flip-chip structure, comprises a sapphire substrate, a u-GaN buffer layer, an electron injection layer, a multi-quantum well active region and a hole injection layer from bottom to top, and is bonded with a driving circuit substrate through a metal bump array, and an insulating material with light transmittance of more than 70% in a wave band of 450nm-470nm is filled in a gap of the metal bump array. Further, the organic large cation is one of 2-phenylethyl ammonium bromide, 4-fluorophenylethyl ammonium bromide, 3-fluorophenylethyl ammonium bromide and 2-fluorophenylethyl ammonium bromide, and the short-chain ammonium bromide is one of ethyl ammonium bromide, propyl ammonium bromide and butyl ammonium bromide. Further, the organic large cations and the short-chain ammonium bromide ligand are cooperatively combined on the surface of the perovskite quantum dot, wherein