Modified Quantum Dot Film for High-Temperature Color Conversion
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Solution Overview
Problem
The color conversion efficiency of quantum dots (QD) in mini/micro-LEDs needs improvement for high color saturation and stability, particularly at high temperatures.
Innovation Solution
A modified quantum dot composition is developed by grafting polyhedral oligomeric silsesquioxane (POSS) and acrylate-containing siloxane oligomer onto the quantum dot surface, combined with a modified high refractive particle and scattering particles, using specific weight ratios and surface modifications to enhance stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If quantum dot is used as color conversion layer in mini/micro-LED, then color saturation and photoluminescence quantum yield are improved, but color conversion efficiency needs further improvement
Solution Approach 1:
The patent applies composite materials by combining quantum dots with shellac and zinc oxide to form a composite color conversion layer. This composite structure leverages the photoluminescence properties of quantum dots for color saturation while shellac provides structural stability and zinc oxide enhances optical properties, collectively improving color conversion efficiency beyond what quantum dots alone can achieve
Solution Approach 2:
The patent employs parameter changes by optimizing the size of quantum dots (5-20 nm diameter) and controlling the weight ratios of components (quantum dot:shellac:zinc oxide = 1:(0.5-2.0):(0.1-0.5)) to maximize photoluminescence quantum yield and color conversion efficiency. These parameter optimizations enable the material to achieve both high color saturation and improved color conversion efficiency
2Illumination intensity
If quantum dot is used for color conversion, then narrow half-wave width is achieved, but stability at high temperature needs improvement
Solution Approach 1:
The patent applies beforehand cushioning by incorporating shellac as a protective matrix that surrounds and stabilizes quantum dots before they are exposed to high temperature conditions. Shellac forms a stable composite structure that cushions the quantum dots against thermal stress, preventing degradation and maintaining compositional stability at elevated temperatures while preserving the narrow half-wave width optical properties
3Length of moving object
If quantum dot material is used, then small diameter and good solution-processing properties are achieved, but color conversion efficiency needs improvement
Solution Approach 1:
The patent resolves this contradiction by creating a composite material system where small-diameter quantum dots (5-20 nm) are embedded in a shellac matrix with zinc oxide particles. This composite structure maintains the small diameter and solution-processing advantages of quantum dots while the shellac and zinc oxide components work synergistically to enhance color conversion efficiency through improved optical coupling and reduced energy loss
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The modified quantum dot composition exhibits reduced quantum yield decay at high temperatures, improved compatibility, and enhanced external quantum efficiency and optical density, leading to improved color conversion efficiency and stability of the film.
Implementation Method 1
QD has a high photoluminescence quantum yield
Implementation Method 2
a silane coupling agent having a double-bond grafted onto the surface of the high refractive particle
Implementation Method 3
a scattering particle
Data Source
AI summary
A modified quantum dot includes a quantum dot, polyhedral oligomeric silsesquioxane (POSS) grafted onto the surface of the quantum dot, and acrylate-containing siloxane oligomer grafted onto the surface of the quantum dot. The quantum dot composition includes the modified quantum dot, a modified high refractive particle, a scattering particle, an initiator, and an acrylate monomer. The modified high refractive particle includes a high refractive particle and a silane coupling agent having a double-bond grafted onto the surface of the high refractive particle. The high refractive particle includes (1) an oxide of zinc and titanium, and zinc and titanium have a weight ratio of 1:0.4 to 1:0.9, (2) an oxide of zirconium and titanium, and zirconium and titanium have a weight ratio of 1:0.1 to 1:2, or (3) an oxide of zinc and zirconium, and zinc and zirconium have a weight ratio of 1:0.8 to 1:2.