Solvent-Free Quantum Dot Curable Composition for Ink-Jetting

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Solution Overview

Problem

Current quantum dot ink compositions face challenges in achieving high light efficiency and suitable viscosity for ink-jetting due to limitations in dispersing quantum dots in polar solvent systems, leading to issues with nozzle clogging and light absorption rates, and there is a need for a solvent-free composition with improved light resistance reliability.

Innovation Solution

A curable composition comprising quantum dots, a polymerizable compound, and a compound with specific structural units represented by Chemical Formulas 1 and 2, which enhances light resistance reliability and sedimentation stability, allowing for higher quantum dot concentrations and improved optical characteristics without the need for solvents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If quantum dots are dispersed in polar solvent system with binder and curable monomer, then composition has suitable viscosity for ink-jetting, but quantum dot content cannot reach 20 wt % or more and light efficiency cannot be increased over certain level

Engineering Contradiction:
Improvequantum dot contentVSAvoidlight efficiency
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent removes the polar solvent system from the composition, extracting the harmful element that limited quantum dot content. By using a solvent-free system with hydrophobic curable monomers, the composition can achieve 20 wt % or more quantum dot content without compromising ink-jetting processability, thereby resolving the contradiction between quantity and reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical parameters of the composition by replacing polar solvents with non-polar hydrophobic curable monomers. This parameter change enables higher quantum dot content (20 wt % or more) while maintaining suitable viscosity for ink-jetting, thus improving both quantity and light efficiency simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If additional quantum dots are added and dispersed to increase light efficiency, then light efficiency improves, but viscosity exceeds 12 cPs and proper processability is not satisfied

Engineering Contradiction:
Improvelight efficiencyVSAvoidviscosity for ink-jetting
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts the polar solvent that caused viscosity issues when quantum dots were added. By using a solvent-free composition with hydrophobic curable monomers, the system can accommodate 20 wt % or more quantum dots while maintaining viscosity within the suitable range for ink-jetting processability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a composite material system combining quantum dots with hydrophobic curable monomers. This composite approach allows high quantum dot content (20 wt % or more) to be achieved while the hydrophobic monomer matrix maintains appropriate viscosity for ink-jetting, resolving the contradiction between light efficiency and ease of operation.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If solvent is added to achieve viscosity range suitable for ink-jetting, then viscosity is satisfied, but nozzle drying, nozzle clogging, and thickness reduction become worse

Engineering Contradiction:
Improveviscosity for ink-jettingVSAvoidnozzle drying and clogging
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent takes out the solvent that caused nozzle drying and clogging issues. By using a solvent-free composition with hydrophobic curable monomers, the system maintains suitable viscosity for ink-jetting (around 12 cPs) without the harmful effects of solvent volatilization, thereby eliminating nozzle drying and clogging problems.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the potential harm of high viscosity into a benefit by using hydrophobic curable monomers that naturally provide suitable viscosity (around 12 cPs) without requiring solvent addition. This eliminates the need for solvent while maintaining processability, turning the viscosity challenge into an advantage by preventing nozzle drying and clogging.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Object-generated harmful factors

If solvent-free quantum dot ink composition is used, then nozzle drying and clogging are prevented, but light resistance reliability needs improvement due to pattern detachment from shrinkage during curing

Engineering Contradiction:
Improvenozzle drying and cloggingVSAvoidlight resistance reliability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent uses a composite material system combining quantum dots with specifically designed hydrophobic curable monomers containing structural units from Chemical Formulas 1 and 2. This composite approach maintains the solvent-free advantage (preventing nozzle drying and clogging) while the specific monomer structure provides adequate adhesion and reduced shrinkage during curing, thereby improving light resistance reliability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical structure parameters of the curable monomer by incorporating specific structural units (Chemical Formulas 1 and 2) that provide both hydrophobicity for suitable viscosity and adequate adhesion properties. This parameter change allows the solvent-free composition to maintain light resistance reliability while preventing pattern detachment during curing.

Inventive Principle:
Principle #35Parameter changes

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 composition achieves excellent light resistance reliability and sedimentation stability, enabling high quantum dot concentrations and improved optical characteristics, suitable for electrohydrodynamic jet printing, while maintaining a viscosity suitable for ink-jetting processes.

Implementation Method 1

a curable composition comprising (A) quantum dots; (B) a polymerizable compound; and (C) a compound including a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS20240343932A1Curable composition, cured layer using the same and display device including the cured layer
Publication Date: 2024.10.17 SAMSUNG SDI CO LTD

AI summary

A curable composition including (A) quantum dots; (B) a polymerizable compound; and (C) a compound including a structural unit represented by Chemical Formula 1 and a structural unit represented by Chemical Formula 2 is provided. A cured layer produced utilizing the curable composition, and a display device including the cured layer are also provided.