Quantum Dot Display Self-Assembled Monolayer Moisture Protection
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Solution Overview
Problem
The existing methods for manufacturing display devices with quantum-dot light-emitting diodes (QLEDs) face challenges such as damage to quantum dots during the process steps for forming red, green, and blue light-emitting layers, and the manufacturing process is complex due to the need for multiple layers and resist handling.
Innovation Solution
A method involving the formation of self-assembled monolayers with non-polar surfaces to create selective regions for quantum-dot application solutions, followed by embedding quantum dots in inorganic matrices using heating and light irradiation, which reduces damage and simplifies the process by eliminating the need for extensive resist handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a layer of metal nitride or metal oxide is formed onto the entire surface to encapsulate quantum dots, then moisture protection is improved, but quantum dot damage occurs during the formation process of subsequent light-emitting layers
Solution Approach 1:
The patent divides the encapsulation function into separate segments: a self-assembled monolayer (SAM) is formed on the surface of each light-emitting layer individually, rather than forming a continuous metal nitride/oxide layer over the entire surface. This segmentation allows the SAM to protect each quantum dot layer from moisture without requiring harsh encapsulation processes that would damage the quantum dots.
Solution Approach 2:
The self-assembled monolayer acts as an intermediary between the quantum dot layer and the external environment. This monolayer provides moisture protection and surface passivation without requiring the formation of thick metal nitride or oxide layers that would otherwise damage the quantum dots during processing.
2Adaptability or versatility
If the liftoff method is used to form light-emitting layers, then manufacturing flexibility is improved, but the process becomes more complex due to multiple resist handling steps
Solution Approach 1:
The patent extracts and eliminates the resist layer and associated development/removal steps from the manufacturing process. By using a self-assembled monolayer that can be selectively removed by oxygen plasma without requiring resist materials, the process complexity is reduced while maintaining the ability to form patterned light-emitting layers.
Solution Approach 2:
The patent replaces the mechanical/chemical resist handling system with a plasma-based removal process. Instead of using resist layers that require development and removal steps, the self-assembled monolayer is removed through oxygen plasma exposure, simplifying the manufacturing process while maintaining patterning capability.
3Adaptability or versatility
If quantum dot layers are formed in sequence (red, green, blue), then complete color coverage is achieved, but quantum dots in earlier layers are damaged by subsequent processing steps
Solution Approach 1:
The patent applies preliminary action by forming the self-assembled monolayer on each quantum dot layer before proceeding to the next layer formation. This preliminary protective measure ensures that each quantum dot layer is protected from potential damage during subsequent processing steps, while still allowing the complete sequence of red, green, and blue layers to be formed for full color coverage.
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 approach reduces damage to quantum dots and simplifies the manufacturing process by creating a stable and efficient method for forming quantum-dot light-emitting layers with reduced moisture exposure and defect prevention.
Implementation Method 1
forming a self-assembled monolayer using a self-assembled monomolecule whose distal end on one side is a non-polar functional group onto a polar surface of an underlayer
Implementation Method 2
forming a first polar surface region that is the polar surface of the underlayer, by light irradiation to remove a part of the self-assembled monolayer
Implementation Method 3
forming a first light-emitting layer including the first quantum dot embedded in a first inorganic matrix composed of the first inorganic material precursor, by performing at least one of heating and light irradiation
Data Source
AI summary
A display device includes the following: a first light-emitting layer including a first inorganic matrix and a first quantum dot; and a self-assembled monolayer composed of monomolecules adjacent to each other, and having a surface that exhibits liquid repellency against a polar solvent, the monomolecules each having a distal end on one side that is a non-polar functional group.