Quantum Dot Ink Composition for Light-Free Polymerization

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Solution Overview

Problem

Current methods for forming quantum dot polymer composites using inkjet processes face challenges in maintaining quantum dot dispersibility and achieving high-quality patterns due to the need for light exposure, which can reduce quantum efficiency and increase defects, and require solvent removal steps that can lead to nozzle clogging and complex processes.

Innovation Solution

An ink composition comprising quantum dots, a metal catalyst such as palladium, an aromatic halide compound, and an ene compound is developed, which reacts to form a polymer matrix without radical generation, allowing for stable droplet discharge and pattern formation without light exposure or solvent removal, ensuring high dispersibility and thermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If light exposure is used for curing the ink composition, then polymerization can be initiated, but quantum dot quantum efficiency is reduced and defects increase

Engineering Contradiction:
Improvepolymerization initiationVSAvoidquantum efficiency reduction
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the curing mechanism from light-based (photopolymerization) to thermal-based (thermopolymerization) by changing the activation parameter from light exposure to temperature control. This allows polymerization to proceed without light exposure, thereby preserving quantum dot quantum efficiency while avoiding the harmful effects of light-induced defects

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the photopolymerization mechanism with a thermopolymerization mechanism. Instead of using light energy to initiate polymerization, the system uses thermal energy and a metal catalyst to drive the polymerization reaction, thereby eliminating the harmful interaction between light and quantum dots

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If solvent removal steps are implemented, then pattern quality is improved, but nozzle clogging occurs and process complexity increases

Engineering Contradiction:
Improvepattern qualityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the solvent removal step from the manufacturing process. By using a solvent-free ink composition where the carrier is a solid metal catalyst that remains in the system, the need for solvent evaporation or removal steps is completely removed, simplifying the process while maintaining pattern quality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The ink composition is designed to be self-sufficient without requiring external solvent removal operations. The metal catalyst serves as both the carrier medium and the polymerization catalyst, eliminating the need for separate solvent removal steps and reducing process complexity

Inventive Principle:
Principle #25Self-service

3Productivity

If metal catalyst amount is increased, then polymerization efficiency is improved, but material consumption increases

Engineering Contradiction:
Improvepolymerization efficiencyVSAvoidcatalyst consumption
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent optimizes the metal catalyst loading to a specific range (0.01-5 wt%, preferably 0.1-1 wt%) to achieve maximum polymerization efficiency with minimal catalyst consumption. This parameter optimization ensures high productivity while minimizing material loss and cost

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 ink composition enables the formation of high-quality quantum dot polymer composite patterns with enhanced mechanical properties and curing degrees, improved thermal stability, and reduced material consumption, while avoiding nozzle clogging and complex process steps.

Implementation Method 1

a metal catalyst; an aromatic halide compound; and an ene compound

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentEP3805337B1Ink compositions and quantum dot polymer composite pattern prepared from the same
Publication Date: 2023.08.09 SAMSUNG DISPLAY CO LTD
  • EP3805337B1 patent drawingFigure 1
  • EP3805337B1 patent drawingFigure 2
  • EP3805337B1 patent drawingFigure 3

AI summary

An ink composition, including a quantum dot; a metal catalyst; an aromatic halide compound; an ene compound including at least one C-H moiety and a carbon-carbon unsaturated bond; and optionally, a metal oxide particle, wherein the metal catalyst is a metal salt, a metal coordination complex, or a combination thereof, wherein the metal catalyst comprises a metal that is palladium, nickel, ruthenium, rhodium, iridium, iron, cobalt, chromium, copper, platinum, silver, gold, or a combination thereof.