Quantum Dot Surface Treatment via Photopolymerization
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Solution Overview
Problem
Quantum dots with nanometer-sized particle diameters are prone to surface instability due to high surface energy, leading to fluorescence emission property deterioration, especially under heat, humidity, and photoexcitation, and have poor compatibility with polar resin materials, causing aggregation and color unevenness in displays.
Innovation Solution
A quantum dot surface treatment method involving continuous supply of a solution containing a silicone compound and a ligand with a coordinating substituent to a light-transmitting reaction flow path for photopolymerization, ensuring uniform coating of the quantum dot surface with a silicone compound, even with large solution amounts, using a surface treatment apparatus with adjustable flow rates and light sources for photoreactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quantum dot surfaces are coated with a polymer or inorganic oxide to enhance stability, then stability is improved, but emission properties deteriorate
Solution Approach 1:
The patent changes the chemical parameters of the coating material by using silane compounds with specific functional groups that can form covalent bonds with quantum dot surfaces. This parameter change allows the coating to provide stability without the adverse effects of conventional polymer or inorganic oxide coatings on emission properties.
Solution Approach 2:
The patent creates a composite structure by forming a silane-based coating layer on quantum dot surfaces. This composite material combines the stability-enhancing properties of silane compounds with the optical properties of quantum dots, achieving both improved stability and maintained emission properties.
2Reliability
If a gas-barrier film is used to enhance quantum dot stability, then stability is improved, but deterioration due to diffusion from film end surface progresses
Solution Approach 1:
The patent extracts the stabilization function from a separate barrier film structure and integrates it directly onto the quantum dot surface through silane coating. This eliminates the film end surface problem by removing the separate barrier film structure while maintaining the stabilization function at the quantum dot level.
Solution Approach 2:
The silane compound acts as an intermediary that directly bonds to the quantum dot surface and provides stabilization. This intermediary approach eliminates the need for a separate barrier film, thereby preventing deterioration from film end surfaces while still providing the desired stability enhancement.
3Reliability
If barrier films are used for quantum dot stabilization, then stability is improved, but the thickness of wavelength conversion material cannot be reduced
Solution Approach 1:
The patent nests the stabilization function directly within the quantum dot structure itself by coating the surface with silane compounds. This nesting approach eliminates the need for separate barrier films, allowing for reduced overall thickness of the wavelength conversion material while maintaining stability.
Solution Approach 2:
The silane coating forms an ultra-thin protective layer on the quantum dot surface, replacing the need for thicker barrier films. This thin film approach provides the necessary stabilization while enabling significant reduction in the overall thickness of the wavelength conversion material.
4Reliability
If quantum dot surfaces are coated to enhance stability, then stability is improved, but the method is difficult to apply to color filters and μLEDs
Solution Approach 1:
The silane coating method provides universal stabilization that can be applied across different quantum dot applications including color filters and μLEDs. The coating process and materials are designed to be broadly applicable, enabling the same stabilization mechanism to work across diverse device types and implementation methods.
5Manufacturing precision
If batch processing is used for quantum dot surface treatment, then emission properties are maintained, but throughput is low
Solution Approach 1:
The patent transitions from batch processing to continuous flow processing for quantum dot surface treatment. This continuous action allows the surface treatment to occur continuously as quantum dots flow through the system, maintaining emission properties while dramatically increasing throughput and productivity.
6Productivity
If large amount of solution is used in batch processing to increase throughput, then productivity is improved, but surface coating becomes incomplete
Solution Approach 1:
The patent replaces the batch processing mechanical system with a continuous flow system where solutions are continuously supplied and reacted. This substitution allows for complete surface coating even with large solution amounts, as the continuous flow ensures adequate contact time and uniform distribution throughout the reaction zone.
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
This method stabilizes quantum dot surfaces, enhances compatibility with resin materials, and maintains fluorescence properties, providing a reliable wavelength conversion material with improved stability and reduced aggregation, suitable for high-throughput production and diverse applications.
Implementation Method 1
a quantum dot having a surface to which a ligand having a coordinating substituent and a reactive substituent is coordinated by virtue of the coordinating substituent
Implementation Method 2
emitting light to the reaction flow path, so that the silicone compound and the reactive substituent undergo a photopolymerization reaction, thereby coating the surface of the quantum dot with the silicone compound
Data Source
AI summary
A quantum dot surface treatment method including continuously supplying a solution containing a silicone compound and a quantum dot having a surface to which a ligand having a coordinating substituent and a reactive substituent is coordinated by virtue of the coordinating substituent, to a reaction flow path made of a material that transmits light, and emitting light to the reaction flow path, so that the silicone compound and the reactive substituent undergo a photopolymerization reaction, thereby coating the surface of the quantum dot with the silicone compound. Thus, the quantum dot surface treatment method is provided that enables to, even in the case of performing surface treatment using a large amount of solution, obtain a quantum dot having excellent stability with high productivity by stably coating the surface of the quantum dot with the silicone compound, and provide a wavelength conversion material with high reliability.