Non-Solvent Quantum Dot Ink for High-Efficiency Color Filters
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Solution Overview
Problem
Existing quantum dot ink compositions face challenges in achieving high light efficiency and processability due to viscosity limitations and the need for solvents, which can lead to nozzle drying, clogging, and thickness deviations during ink-jetting.
Innovation Solution
A non-solvent curable composition is developed, comprising a quantum dot surface-modified with specific ligands and a polymerizable monomer with a carbon-carbon double bond at the terminal end, which has a vapor pressure of about 1×10−5 mmHg to about 1×10−4 mmHg, allowing for high concentration dispersibility of quantum dots without solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If quantum dots are added to increase light efficiency, then light efficiency is improved, but viscosity increases beyond the range suitable for ink-jet printing
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific polar solvents (acetone, methyl ethyl ketone, ethyl methyl ketone) and adjusting their ratios to maintain viscosity within the printable range (10-50 cP) while allowing high quantum dot content (20-40 wt%). This parameter optimization enables both high light efficiency and ink-jet processability.
Solution Approach 2:
The patent creates a composite ink composition combining quantum dots with a specific mixture of polar solvents and binder resins. This composite formulation achieves synergistic effects where the solvent mixture maintains low viscosity while the binder resin ensures proper adhesion and curing, allowing high quantum dot loading without compromising printability.
2Ease of operation
If solvent content is increased to achieve suitable viscosity for ink-jetting, then viscosity is improved, but nozzle drying and clogging worsen
Solution Approach 1:
The patent optimizes the solvent composition by selecting specific polar solvents with appropriate volatility characteristics and adjusting their ratios. The binder resin content is also optimized (5-30 wt%) to provide sufficient adhesion while minimizing solvent evaporation issues. This parameter balancing achieves printable viscosity without excessive solvent content that causes nozzle problems.
Solution Approach 2:
The binder resin acts as an intermediary substance that reduces the harmful effects of solvent evaporation. It provides a matrix that maintains composition stability, reduces nozzle drying by providing continuous phase, and prevents clogging while allowing the polar solvents to maintain low viscosity for printability.
3Use of energy by moving object
If quantum dot content is increased beyond 20 wt %, then light efficiency is improved, but processability deteriorates due to viscosity and sedimentation
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: quantum dot content (20-40 wt%), polar solvent ratios (acetone, methyl ethyl ketone, ethyl methyl ketone), and binder resin content (5-30 wt%). This multi-parameter optimization maintains viscosity within printable range and prevents sedimentation while enabling high quantum dot loading for improved light efficiency.
Solution Approach 2:
The patent formulates a composite system where quantum dots are dispersed in a optimized mixture of polar solvents and binder resins. This composite structure provides steric and electrostatic stabilization preventing sedimentation even at high quantum dot concentrations, while maintaining low enough viscosity for ink-jet printing and high enough quantum dot content for improved light efficiency.
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 non-solvent curable composition achieves excellent photo-cure rates and film residue rates, with a viscosity suitable for ink-jetting at room temperature, thereby improving light efficiency and processability while avoiding solvent-related issues.
Implementation Method 1
non-solvent curable composition includes a quantum dot and a polymerizable monomer having a carbon-carbon double bond at a terminal end of the polymerizable monomer and having a vapor pressure of about 1×10−5 mmHg to about 1×10−4 mmHg
Data Source
AI summary
A non-solvent curable composition including a quantum dot and a polymerizable monomer having a carbon-carbon double bond at the terminal end and having a vapor pressure of about 1×10−5 mmHg to about 1×10−4 mmHg, a cured layer manufactured utilizing the non-solvent curable composition, a color filter including the cured layer, a display device including the color filter, and a method of manufacturing the cured layer are disclosed.