Quantum Dot Encapsulation Pockets to Block Edge Ingress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for encapsulating quantum dots to protect them from oxygen and water vapor degradation are complex, expensive, and prone to edge ingress, limiting their large-scale deployment in applications like lighting and displays, where stability over thousands of hours is required.
Innovation Solution
A method for preparing pockets of encapsulated material where core quantum dots are fully surrounded by a barrier material, using a process involving the formation of bases, core deposits, and lids, with localized curing and removal of uncured materials, allowing for versatile shapes and scalable fabrication without the need for multilayered encapsulation techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thin film encapsulation (TFE) approach is used to protect quantum dots, then quantum dots are protected from oxygen and water vapor, but edge ingress effects occur to the lateral sides
Solution Approach 1:
The encapsulation structure is divided into multiple discrete bead units, each independently encapsulating quantum dots. This segmentation prevents continuous edge ingress pathways that plague thin film encapsulation, as each bead acts as an isolated protective unit with no lateral edges exposed to the environment.
Solution Approach 2:
The encapsulation employs a nested multilayer structure where inorganic barrier layers (SiO2, TiO2, or Al2O3) are embedded within organic polymer matrix layers. This nested arrangement creates tortuous gas diffusion pathways that block oxygen and water vapor while the outer polymer layers seal the inorganic layers, preventing edge ingress at the lateral sides.
2Reliability
If multilayer barrier approach is applied to protect quantum dots, then gas diffusion is blocked, but fabrication process becomes complex and expensive
Solution Approach 1:
The patent combines multiple barrier functions into a single integrated bead encapsulation unit. Instead of requiring separate deposition steps for each inorganic layer in a planar multilayer structure, the entire multilayer barrier system is formed within each spherical bead through a unified sol-gel or co-precipitation process, dramatically simplifying fabrication while maintaining the gas diffusion blocking capability.
Solution Approach 2:
The invention changes the physical state and formation parameters of the barrier layers by using solution-based sol-gel chemistry or co-precipitation methods instead of vacuum deposition techniques. This allows the multilayer inorganic structure to form from liquid precursors at low temperatures, enabling simple drop-casting or spin-coating processes that are inexpensive and scalable while producing the same protective function.
3Manufacturing precision
If quantum dots are deposited directly on blue LED chip (on-chip approach), then emission color and intensity can be controlled, but local heating accelerates quantum dot degradation
Solution Approach 1:
The encapsulated bead structure serves as an intermediary thermal management layer between the blue LED chip and quantum dots. The polymer matrix and porous inorganic layers within each bead provide thermal isolation, reducing direct heat transfer from the high-temperature LED chip to the temperature-sensitive quantum dots, thereby protecting them from thermal degradation while still enabling optical coupling for color conversion.
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 effectively prevents edge ingress and maintains the emission efficiency of quantum dots over extended periods, enabling their reliable use in lighting and display applications by providing a robust and efficient encapsulation that is compatible with large-scale fabrication.
Implementation Method 1
Gas diffusion barriers need to be implemented in some sort in quantum dots based devices
Implementation Method 2
The multilayer barrier approach is designed to circumvent the inevitable presence of defects in the inorganic layer, by creating tortuous pathways for gas diffusion
Data Source
AI summary
The invention relates to a method to prepare pockets comprising encapsulated material. The pockets are formed by first forming one or more bases B of barrier material on a substrate, by subsequently applying core material on at least part of the bases B and by forming a lid L on bases B provided with core material. The core material comprises at least one photoemissive particle or photoemissive compound such as quantum dots. The invention also relates to a pocket or a plurality of pockets comprising encapsulated material obtained by such method, to a device comprising at least one pocket of encapsulating material and to a process to transfer such a pocket of encapsulated material from one substrate to another substrate.