Quantum Dot Polymer Composition for Moisture-Stable Emission
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Solution Overview
Problem
Existing methods for stabilizing quantum dots in wavelength conversion members, such as those used in liquid crystal displays, often require barrier films that increase thickness and cost, and existing ligand treatments lead to aggregation and decreased quantum yield under high temperature and humidity conditions.
Innovation Solution
A quantum dot-containing polymer is formed by coordinating a ligand with reactive substituents to the quantum dot surface and a silicone compound with polymerizable substituents, which is then photopolymerized to enhance steric hindrance and suppress aggregation, maintaining quantum yield and emission stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If barrier films are used to stabilize quantum dots against moisture and oxygen, then stability is improved, but thickness and cost increase
Solution Approach 1:
The patent applies nested protection by incorporating quantum dots within polymer beads, which are then embedded in a resin layer. This multi-level nesting structure provides comprehensive protection against moisture and oxygen without requiring separate barrier films, thus maintaining thinness while improving stability
Solution Approach 2:
The patent uses composite material structures combining hydrophobic resin layers with hydrophilic polymer-containing layers. This composite approach creates synergistic protection where each material contributes its strengths, achieving high stability without the need for additional barrier films that would increase thickness
2Strength
If ligand treatment is applied to increase quantum dot concentration in polymer beads, then adhesion is improved, but aggregation occurs and quantum yield decreases under high temperature and humidity
Solution Approach 1:
The patent changes the chemical parameters of the ligand by introducing hydrophobic groups and controlling the balance between hydrophilic and hydrophobic components. This parameter optimization allows strong adhesion while preventing aggregation under high temperature and humidity conditions, maintaining quantum yield
Solution Approach 2:
The patent applies local quality by creating regions with different hydrophobicity within the polymer bead structure. The ligand treatment is optimized to provide appropriate local properties that enhance adhesion at the quantum dot surface while preventing unwanted aggregation in the bulk material
3Reliability
If silazane coating treatment is applied to improve heat and moisture resistance, then stability is improved, but quantum yield is lowered due to photocuring with short ultraviolet rays
Solution Approach 1:
The patent uses the polymer bead structure as an intermediary protective layer between the quantum dots and the harsh environment. This intermediary provides heat and moisture resistance without requiring direct silazane coating on the quantum dots, thereby avoiding the quantum yield reduction caused by UV photocuring
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 method produces a stable quantum dot-containing polymer that maintains quantum yield and emission stability under high temperature and humidity conditions without the need for barrier films, reducing thickness and cost while preventing aggregation.
Implementation Method 1
coordinating a ligand with reactive substituents to the quantum dot surface
Implementation Method 2
silicone compound with polymerizable substituents, which is then photopolymerized
Implementation Method 3
quantum dots that emit fluorescence by excitation light
Implementation Method 4
when crystal size becomes smaller than Bohr radius of excitons, a strong quantum confinement effect occurs and energy levels become discrete
Data Source
AI summary
A quantum dot-containing polymer contains quantum dots that emit fluorescence by excitation light, wherein the quantum dot-containing polymer is a combined polymer of the quantum dots in which a ligand having a reactive substituent is coordinated to the outermost surface and a silicone compound having a polymerizable substituent. The quantum dot-containing polymer is stabilized by mild conditions.