ZnS1-xOx Core/Shell Quantum Dot for LED Efficiency

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Solution Overview

Problem

Current Quantum Dot Light-Emitting Diodes (QLEDs) suffer from inefficiencies due to the imbalance of electron and hole migration, resulting in low brightness and efficiency, primarily because the electron transport layer using zinc oxide has a faster electron migration speed than the hole transport layer, leading to defects in the quantum dot electroluminescent layer.

Innovation Solution

A core/shell quantum dot structure is introduced, where the surface shell is ZnS1−xOx with 0.1≤x≤0.9, and is connected with surface ligands such as sulfhydryl, carboxyl, or organic ester groups, and is prepared by introducing oxygen into a dispersion liquid containing an initial quantum dot to form a ZnS1−xOx surface shell, enhancing conductivity and light-emitting efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If zinc oxide is used as the electron transport layer, then electron migration speed is fast, but hole migration speed is slow, resulting in electron-hole imbalance

Engineering Contradiction:

Improveelectron migration speedVSAvoidelectron-hole balance

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent changes the chemical composition parameter of the quantum dot surface shell from pure ZnS to ZnS1-xOx with controlled oxygen content (x=0.1-0.9), thereby modifying the electrical properties to achieve better electron-hole balance while maintaining fast electron transport

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material structure by combining ZnS and ZnO in the surface shell layer, forming ZnS1-xOx that integrates the advantages of both materials: fast electron transport from ZnO and stable structure from ZnS, achieving balanced electron-hole migration

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If traditional ZnS shell is used, then structure is stable, but conductivity is insufficient, resulting in low brightness and efficiency

Engineering Contradiction:

Improvestructure stabilityVSAvoidconductivity

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent modifies the compositional parameter of the surface shell by introducing oxygen at controlled concentrations (x=0.1-0.9 in ZnS1-xOx), which enhances the electrical conductivity while preserving the structural stability and protective function of the ZnS framework

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 core/shell quantum dot structure significantly improves the conductivity and brightness of QLEDs, enhancing External Quantum Efficiency (EQE) and facilitating better electron-hole combination in the light-emitting layer, leading to improved performance and efficiency.

Implementation Method 1

introducing oxygen into a dispersion liquid containing an initial quantum dot to form a ZnS1−xOx surface shell

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS20240188418A1Core/shell quantum dot for Light-Emitting Diode and Preparation Method therefor, and Light-Emitting Diode

Publication Date: 2024.06.06 SUZHOU XINGSHUO NANOTECH CO LTD

AI summary

The present disclosure provides a core/shell quantum dot for a Light-Emitting Diode (LED) and a preparation method therefor, and an LED. The core/shell quantum dot includes a core body and a surface shell; and the surface shell is ZnS1−xOx, wherein 0.1≤x≤0.9. The core-shell quantum dot of the present disclosure can significantly improve the current density, brightness, and external quantum efficiency of the LED prepared therefrom.