Halide-Stabilized Core-Shell Quantum Dots for Device Heat Exposure

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Solution Overview

Problem

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

Innovation Solution

A quantum dot design featuring a core and shell with a first semiconductor nanocrystal containing zinc and sulfur, and a second semiconductor nanocrystal with a different composition, where the first nanocrystal includes a metal and halogen acting as a Lewis acid in a halide form, with specific mole percentages to enhance stability and maintain photoluminescence characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If quantum dots are integrated into devices with mediums and heat treatments, then device functionality is achieved, but surface damage occurs leading to reduced photoluminescence efficiency

Engineering Contradiction:

Improvephotoluminescence efficiencyVSAvoidsurface damage from mediums and heat treatments

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies beforehand cushioning by introducing a protective shell structure around the quantum dot core before device integration. This shell acts as a cushioning layer that protects the core from surface damage caused by mediums and heat treatments during device operation, thereby maintaining photoluminescence efficiency throughout the device lifecycle.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent employs composite materials by creating a core-shell structure where the quantum dot core is combined with a protective shell made of different materials. This composite structure allows the core to maintain its photoluminescence properties while the shell provides protection against environmental damage, resolving the contradiction between device integration requirements and surface damage prevention.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If quantum dots undergo heat treatment during device integration, then device manufacturing is completed, but thermal stability decreases leading to efficiency loss

Engineering Contradiction:

Improvedevice integrationVSAvoidthermal stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The protective shell is introduced beforehand to cushion the quantum dot core against thermal stress during device manufacturing and heat treatment processes. This allows the quantum dots to undergo necessary heat treatments for device integration while the shell maintains thermal stability and prevents efficiency loss.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent applies parameter changes by modifying the shell composition and structure to have high thermal stability parameters. The shell materials and their ratios are specifically selected and optimized to withstand heat treatment temperatures, allowing the quantum dots to maintain stability during device manufacturing processes.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If metal and halogen are added to enhance stability, then photoluminescence characteristics are improved, but quantum dot complexity increases

Engineering Contradiction:

Improvephotoluminescence characteristicsVSAvoidquantum dot composition

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by concentrating the metal and halogen elements specifically within the shell structure rather than distributing them throughout the entire quantum dot. This localized approach enhances photoluminescence characteristics and stability in the critical surface region while minimizing overall compositional complexity and maintaining simplicity in the core structure.

Inventive Principle:

Principle #3Local quality

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 enhanced quantum dot structure maintains improved photoluminescence and thermal stability, minimizing efficiency loss when integrated into devices, and ensures effective light absorption per unit weight.

Implementation Method 1

the first semiconductor nanocrystal includes a metal and a halogen that are configured to act as a Lewis acid in a halide form

Methodology Applied

Scientific EffectLewis acid-base interaction:

Implementation Method 2

Quantum dots have a large surface area per unit volume due to very small particle sizes and exhibit quantum confinement effects

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentUS11740495B2Quantum dots and devices including the same

Publication Date: 2023.08.29 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.