Quantum Dot LED Hole Injection Layer Using P-Type Oxide Semiconductor

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Solution Overview

Problem

Conventional quantum dot light-emitting diodes face challenges with hole transport processes, particularly due to the use of PEDOT:PSS, which requires lengthy annealing times and can damage ITO electrodes, and most oxide semiconductors exhibit n-type characteristics, making it difficult to implement p-type doping.

Innovation Solution

A quantum dot light-emitting diode using a p-type oxide semiconductor represented by Cu2Sn2-XS3—(GaX)2O3 as the hole injection layer, fabricated through a solution process, allowing for a low-temperature process and reduced preparation costs, with heat treatment or ultraviolet light/ozone treatment to optimize properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PEDOT:PSS is used as a hole injection layer, then high conductivity is achieved, but annealing time is required resulting in longer process time and ITO electrode damage

Engineering Contradiction:

Improvehole injection capabilityVSAvoidprocess time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the material composition parameters by incorporating Ga2O3 into the Cu2SnS3 oxide semiconductor, adjusting the molar ratio to achieve p-type characteristics with optimized conductivity and work function, eliminating the need for lengthy annealing processes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite oxide semiconductor material Cu2SnS3—Ga2O3 that combines the advantages of both materials, achieving p-type characteristics with high conductivity and stability, replacing the conventional PEDOT:PSS organic material

Inventive Principle:

Principle #40Composite materials

2Reliability

If PEDOT:PSS is used as a hole injection layer, then high conductivity is achieved, but the surface of ITO electrode may be damaged and device stability deteriorates

Engineering Contradiction:

Improvehole injection capabilityVSAvoidITO electrode damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the chemical composition parameters of the hole injection layer by incorporating Ga2O3 to achieve p-type characteristics with appropriate work function (4.5-5.5 eV), eliminating the strongly acidic properties that cause ITO damage while maintaining high conductivity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the typically harmful n-type characteristics of oxide semiconductors into beneficial p-type characteristics through Ga2O3 doping, transforming a material class known for causing instability into a stable, ITO-friendly hole injection layer

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If conventional oxide semiconductors are used, then transparency and mobility are achieved, but n-type characteristics make p-type doping difficult

Engineering Contradiction:

Improvetransparency and mobilityVSAvoidp-type doping capability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the doping parameters and material composition by introducing Ga2O3 at controlled molar ratios (0.1-0.5), successfully achieving p-type characteristics in oxide semiconductors while preserving their inherent transparency and high mobility properties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality modification by selectively doping specific regions with Ga2O3 to create p-type characteristics only where needed, maintaining the overall amorphous or polycrystalline structure that provides transparency and mobility

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 use of p-type oxide semiconductor layers improves the electrical properties of quantum dot light-emitting diodes, enhancing hole mobility and reducing resistivity, resulting in improved current density, luminance, and efficiency compared to traditional PEDOT:PSS-based devices.

Implementation Method 1

the hole injection layer is a p-type oxide semiconductor... improves the electrical properties of quantum dot light-emitting diodes, enhancing hole mobility and reducing resistivity

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

with heat treatment or ultraviolet light/ozone treatment to optimize properties

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

with heat treatment or ultraviolet light/ozone treatment to optimize properties

Methodology Applied

Scientific EffectPhoto-oxidation: Photo-oxidation

Data Source

PatentUS11600796B2Quantum dot light-emitting diode and method of fabricating the same

Publication Date: 2023.03.07 UNIVERSITY INDUSTRY COOPERATION GROUP OF KYUNG HEE UNIVERSITY

AI summary

Disclosed is a quantum dot light-emitting diode including a positive electrode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and a negative electrode, wherein the hole injection layer is a p-type oxide semiconductor represented by Formula 1 below:Cu2Sn2-XS3—(GaX)2O3, [Formula 1]wherein X is greater than 0.2 and less than 1.5 (0.2<x<1.5).