Core-Shell Quantum Dots for Heat-Stable Photoluminescence

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Solution Overview

Problem

Quantum dots with core-shell structures, particularly InP/ZnSeS, face efficiency drops when used in devices due to surface damage from mediums and heat treatments, leading to reduced photoluminescence properties.

Innovation Solution

A quantum dot design with a core and shell where one includes zinc and sulfur with a metal and halogen acting as a Lewis acid, and the other has a different semiconductor composition, optimized to maintain photoluminescence and thermal stability, avoiding cadmium and heavy metals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If quantum dots undergo heat treatment and medium interactions in device manufacturing, then device fabrication is enabled, but photoluminescence efficiency and thermal stability deteriorate

Engineering Contradiction:

Improvedevice fabricationVSAvoidphotoluminescence efficiency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-coating the quantum dot surface with a protective shell structure before the quantum dots are exposed to harmful heat treatment and medium interactions during device manufacturing. This protective layer is formed in advance to prevent subsequent damage to the photoluminescence properties

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements beforehand cushioning by introducing a protective shell that acts as a buffer between the quantum dot core and the harmful external environment. This shell absorbs and mitigates the damaging effects of heat treatment and medium exposure before they can reach and damage the photoluminescent core

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Adaptability or versatility

If quantum dots are exposed to surface damage from mediums and heat treatments, then device integration is achieved, but thermal stability and photoluminescence properties are reduced

Engineering Contradiction:

Improvedevice integrationVSAvoidthermal stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent uses an intermediary approach by introducing a protective shell as a mediator between the quantum dot core and the external environment. This shell composition is specifically designed to be stable under heat treatment and medium exposure while protecting the core, allowing device integration without compromising thermal stability

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If quantum dots use traditional compositions, then photoluminescence efficiency is high, but environmental toxicity and thermal stability are poor

Engineering Contradiction:

Improvephotoluminescence efficiencyVSAvoidenvironmental toxicity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies composite materials by creating a core-shell structure where the core maintains high photoluminescence efficiency with improved composition, and the shell provides environmental stability and toxicity reduction. The composite structure combines the advantages of different materials to achieve both performance and safety

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent implements parameter changes by modifying the chemical composition parameters of the quantum dot core and shell to eliminate cadmium and heavy metals while maintaining photoluminescence efficiency. The composition is adjusted to use environmentally friendly alternatives with comparable or superior optical properties

Inventive Principle:

Principle #35Parameter changes

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 quantum dot maintains improved photoluminescence characteristics and thermal stability, minimizing efficiency loss from medium interactions and heat treatments, while maintaining light absorption, suitable for display devices.

Implementation Method 1

the first semiconductor nanocrystal further includes a metal and a halogen, the metal and the halogen being configured to act as a Lewis acid in a halide form

Methodology Applied

Scientific EffectLewis acid:

Implementation Method 2

The quantum dot maintains improved photoluminescence characteristics and thermal stability, minimizing efficiency loss from medium interactions and heat treatments, while maintaining light absorption

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentUS12130508B2Quantum dots and devices including the same

Publication Date: 2024.10.29 SAMSUNG DISPLAY CO LTD

AI summary

A quantum dot including a core and a shell disposed on the core wherein one of the core and the shell includes a first semiconductor nanocrystal including zinc and sulfur and the other of the core and the shell includes a second semiconductor nanocrystal having a different composition from the first semiconductor nanocrystal, the first semiconductor nanocrystal further includes a metal and a halogen configured to act as a Lewis acid in a halide form, an amount of the metal is greater than or equal to about 10 mole percent (mol %) based on a total number of moles of sulfur, and an amount of the halogen is greater than or equal to about 10 mol % based on a total number of moles of sulfur, a method of producing the same, and a composite and an electronic device including the same.