Quantum Dot Polymer Matrix Crosslinking for Brightness and Durability

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Solution Overview

Problem

Current wavelength conversion members in liquid crystal display devices using quantum dots face challenges in achieving high brightness and durability, with existing solutions often compromising between brightness and long-term stability.

Innovation Solution

A polymerizable composition comprising quantum dots, polyfunctional thiols, and specific (meth)acrylates is developed, where the polyfunctional thiol and (meth)acrylates undergo crosslinking reactions to enhance ligand coverage on quantum dots, improving brightness and durability by preventing ligand exchange and ensuring stable light emission over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional wavelength conversion members use quantum dots with standard ligand coverage, then the structure is simple and ease of manufacture is improved, but brightness and durability deteriorate

Engineering Contradiction:

Improveease of manufactureVSAvoidbrightness

Core Design Contradiction:

Ease of manufactureVSIllumination intensity

Solution Approach 1:

The patent uses a composite polymer matrix system combining polyfunctional thiol and (meth)acrylate components that work synergistically to enhance quantum dot stability and brightness through crosslinking reactions, creating a multi-component material system that simultaneously improves optical performance and manufacturing feasibility

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical parameters of the ligand environment by using polyfunctional thiols with multiple reactive groups, changing the molecular weight ratios and functional group densities to optimize both brightness enhancement and crosslinking density for improved durability

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional wavelength conversion members use quantum dots with standard ligand coverage, then the structure is simple and ease of manufacture is improved, but durability deteriorates

Engineering Contradiction:

Improveease of manufactureVSAvoiddurability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent employs a composite polymer system where polyfunctional thiol and (meth)acrylate components create a crosslinked network that simultaneously protects quantum dots from degradation while maintaining manufacturing feasibility through solution processing and standard curing methods

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The polyfunctional thiol acts as an intermediary between the quantum dot surface and the polymer matrix, providing strong coordination to the quantum dot while also participating in crosslinking reactions with (meth)acrylate, thereby mediating the interface to enhance durability

Inventive Principle:

Principle #24Intermediary (Mediator)

3Illumination intensity

If polyfunctional thiol and (meth)acrylate crosslinking is implemented to improve brightness, then brightness is improved, but device complexity increases

Engineering Contradiction:

ImprovebrightnessVSAvoiddevice complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent merges the ligand coordination function of polyfunctional thiol with the crosslinking function of (meth)acrylate into a single integrated polymerization process, combining multiple functions (stabilization, crosslinking, matrix formation) into one step rather than requiring separate processing steps

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If polyfunctional thiol and (meth)acrylate crosslinking is implemented to improve durability, then durability is improved, but device complexity increases

Engineering Contradiction:

ImprovedurabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the durability-enhancing crosslinking function with the matrix formation process by using (meth)acrylate that simultaneously provides both structural matrix and crosslinking capability, integrating multiple protective functions into a single material system

Inventive Principle:

Principle #5Merging (Combining)

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 proposed solution enables wavelength conversion members to emit light with high brightness and maintain stability over extended periods, effectively addressing the limitations of existing technologies by combining improved brightness with enhanced durability.

Implementation Method 1

quantum dots are excited by the incident light to emit fluorescence

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 2

the polyfunctional thiol and (meth)acrylates undergo crosslinking reactions to enhance ligand coverage on quantum dots

Methodology Applied

Scientific EffectCrosslinking reaction: Chemical Bonding

Data Source

PatentUS20230096684A1Quantum dot-containing polymerizable composition, cured product, wavelength conversion member, backlight unit, and liquid crystal display device

Publication Date: 2023.03.30 FUJIFILM CORP

AI summary

Provided is a polymerizable composition including a quantum dot, a polyfunctional thiol, a first (meth)acrylate, and a second (meth)acrylate, in which the first (meth)acrylate is a polyfunctional (meth)acrylate, the second (meth)acrylate is a mono- or higher functional (meth)acrylate having a functional group selected from the group consisting of a carboxy group, a hydroxy group, a phosphate group, and an amino group, and a molecular weight of the second (meth)acrylate is equal to or less than a molecular weight of the polyfunctional thiol.