Quantum Dot Polymer Composite Patterning via Carboxylic Acid Binder
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Solution Overview
Problem
Current methods for patterning quantum dot-polymer composites face challenges due to poor compatibility between quantum dots and conventional photoresists, leading to agglomeration and difficulty in achieving desired amounts of quantum dots in the polymer matrix, which affects the formation of high-quality color filters with wide viewing angles and high luminance.
Innovation Solution
A photosensitive composition comprising quantum dots, a carboxylic acid group-containing binder with a multiple aromatic ring polymer, and a photopolymerizable monomer, where the binder disperses quantum dots without the need for surface treatment, allowing for the formation of a quantum dot-polymer composite pattern using an alkali-developable photoresist process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photoresist is used for patterning quantum dots, then the photoresist can be applied to form patterns, but the quantum dots agglomerate and cannot be uniformly dispersed in the polymer matrix
Solution Approach 1:
The patent modifies the chemical parameters of the binder by incorporating carboxylic acid groups with specific acid values (50-150 mg KOH/g) and designing polymers with specific backbone structures containing quaternary carbon atoms and aromatic rings. These parameter changes enable the binder to interact with quantum dot surfaces, preventing agglomeration and achieving uniform dispersion without requiring quantum dot surface treatment.
Solution Approach 2:
The patent creates a composite binder system combining multiple aromatic ring-containing polymers with carboxylic acid groups. This composite material approach allows the binder to simultaneously provide structural integrity and chemical interaction with quantum dots, resolving the compatibility issue between quantum dots and conventional photoresist formulations.
2Reliability
If quantum dot surface treatment is performed to improve dispersion, then compatibility with photoresist improves, but additional processing steps are required
Solution Approach 1:
The carboxylic acid group-containing binder acts as an intermediary between the quantum dots and the photoresist system. Instead of modifying the quantum dot surface directly, the binder mediates the interaction by providing chemical groups that interact with quantum dot surfaces, enabling uniform dispersion and compatibility without additional quantum dot treatment steps.
Solution Approach 2:
The binder is designed to automatically interact with quantum dots through its carboxylic acid groups, which self-organize to disperse quantum dots uniformly. This self-service mechanism eliminates the need for separate quantum dot surface treatment processes, as the binder performs the dispersion function inherently during the photoresist formulation process.
3Device complexity
If absorption-type color filter is used in LCD, then the structure is simple, but the light transmittance is low resulting in narrow viewing angle and low luminance
Solution Approach 1:
The patent changes the optical parameters of the color filter by incorporating quantum dots with specific size ranges (2-10 nm) that exhibit quantum confinement effects. These quantum dots convert blue light to red light with high efficiency, transforming the color filter from an absorption-type to a light-conversion type, thereby increasing overall light transmittance and luminance while maintaining viewing angle.
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 solution enables uniform dispersion and patterning of quantum dots, improving the compatibility and stability of the quantum dot-polymer composite, resulting in a color filter with enhanced brightness, wide viewing angles, and high color reproducibility without the need for additional surface treatments or organic solvents.
Implementation Method 1
a photopolymerizable monomer having a carbon-carbon double bond; and a photoinitiator
Implementation Method 2
the binder disperses quantum dots without the need for surface treatment
Data Source
AI summary
A photosensitive composition including: a plurality of quantum dots, wherein the quantum dot includes an organic ligand with a hydrophobic moiety bound to a surface of the quantum dot; a binder; a photopolymerizable monomer having a carbon-carbon double bond; a photoinitiator; and a solvent, wherein the binder includes a multiple aromatic ring-containing polymer including a main chain including a carboxylic acid group and a backbone structure incorporated in the main chain, wherein the backbone structure includes a quaternary carbon atom, which is a part of a cyclic group, and two aromatic rings bound to the quaternary carbon atom, and wherein the plurality of quantum dots are dispersed in the binder.