Quantum Dot Multi-Layer Encapsulation for Humidity Resistance

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Solution Overview

Problem

Quantum dots in lighting and display devices are prone to degradation from water vapor and oxygen, leading to a short lifespan, as existing coatings are insufficient in providing comprehensive protection.

Innovation Solution

A method involving the formation of a semiconductor structure with a nanocrystalline core and shell, encapsulated in multiple layers of polymeric organic and inorganic materials, including silica, to create a robust and stable quantum dot with enhanced thermal and humidity resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single coating layer is applied to quantum dots, then the device structure is simple and manufacturing is easier, but the protection against water vapor and oxygen is insufficient leading to short lifespan

Engineering Contradiction:

Improvelifespan of quantum dot devicesVSAvoidcoating structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protective coating is divided into multiple distinct layers: an inner inorganic insulator layer (silica or silicon oxide) providing barrier protection, and an outer polymeric organic material layer providing environmental stability. This segmentation allows each layer to perform its specific protective function, creating comprehensive protection against water vapor and oxygen that extends device lifespan

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a nested coating structure where the polymeric organic material layer encapsulates the inorganic insulator layer, which in turn encapsulates the quantum dot. This nested arrangement creates multiple barriers that environmental degradants must penetrate, significantly enhancing protection while maintaining a compact structure

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If multiple insulating layers are formed to protect quantum dots, then protection against environmental degradants is significantly improved, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveprotection against water vapor and oxygenVSAvoidcoating process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The inorganic insulator layer serves as an intermediary between the quantum dot and the polymeric organic material layer. This intermediate layer facilitates the coating process by providing a stable surface for polymer deposition and ensures proper adhesion between the quantum dot and outer protective layer, simplifying the overall manufacturing process despite the multi-layer structure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent combines inorganic insulator materials (silica, silicon oxide) with polymeric organic materials to create a composite coating structure. This composite approach leverages the advantages of both material types: the inorganic layer provides excellent barrier properties and thermal stability, while the organic polymer layer provides environmental stability and protection. The combination creates a robust protective system that can be manufactured using established coating techniques

Inventive Principle:

Principle #40Composite materials

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 multi-layer encapsulation significantly extends the lifespan of quantum dot-based devices by creating a tortuous path for environmental degradants, ensuring thermal stability and maintaining photoluminescence performance under various conditions.

Implementation Method 1

forming a layer of polymeric organic material that encapsulates the quantum dot to create a coated quantum dot

Methodology Applied

Scientific EffectEncapsulation: Physical Containment

Implementation Method 2

Multiple insulating layers can then be formed, further encapsulating the quantum dot... creating a tortuous path for environmental degradants

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS10407613B2Composition of, and method for forming, a semiconductor structure with polymer and insulator coatings

Publication Date: 2019.09.10 OSRAM OPTO SEMICON GMBH & CO OHG

AI summary

A semiconductor structure includes a quantum dot. A polymeric organic layer encapsulates the quantum dot to create a coated quantum dot, and at least one additional organic layer and/or inorganic insulator layer encapsulates the coated quantum dot, wherein forming the one or more layers of organic material that encapsulates the coated quantum dot comprises forming a plurality of layers of polymers using a layer-by-layer deposition process.