Light-emitting Element Intermediate Layer Quenching Suppression

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Solution Overview

Problem

Existing light-emitting devices face challenges in suppressing quenching due to the limited thickness of the interface layer, which inhibits hole injection and increases voltage, making it difficult to maintain sufficient distance between the light-emitting and charge transport layers.

Innovation Solution

Incorporating an intermediate layer with a larger ionization potential and smaller electron affinity between the light-emitting layers, formed using inorganic materials like metal oxides, to create an energy barrier and separate the light-emitting region from the charge transport layers, thereby enhancing film thickness and reducing quenching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the film thickness of the interface layer is increased to maintain sufficient distance between light-emitting layer and charge transport layer, then quenching is suppressed, but hole injection into the light-emitting layer is inhibited and voltage becomes higher than desired

Engineering Contradiction:

ImprovequenchingVSAvoidvoltage

Core Design Contradiction:

Object-affected harmful factorsVSPower

Solution Approach 1:

The charge transport layer is segmented into a first charge transport layer adjacent to the light-emitting layer and a second charge transport layer adjacent to the intermediate layer. This segmentation allows the first charge transport layer to maintain close proximity to the light-emitting layer for effective hole injection, while the intermediate layer separates the second charge transport layer to prevent quenching, thus resolving the contradiction between suppressing quenching and maintaining hole injection efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An intermediate layer is introduced between the light-emitting layer and the second charge transport layer. This intermediate layer acts as a mediator that provides sufficient distance to prevent quenching while allowing the first charge transport layer to remain adjacent to the light-emitting layer for effective hole injection, thereby resolving the voltage increase issue

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

Engineering Contradiction:

ImprovequenchingVSAvoidhole injection

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The charge transport layer is divided into two distinct layers: the first charge transport layer positioned adjacent to the light-emitting layer to facilitate hole injection, and the second charge transport layer positioned adjacent to the intermediate layer to prevent quenching. This segmentation enables both hole injection reliability and quenching suppression to be achieved simultaneously

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The intermediate layer serves as an intermediary structure that separates the second charge transport layer from the light-emitting layer, preventing quenching while allowing the first charge transport layer to remain in direct contact with the light-emitting layer for effective hole injection, thus maintaining hole injection reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This configuration effectively suppresses quenching by maintaining a sufficient distance for light emission, improving luminance efficiency and reducing drive voltage while ensuring reliable long-term performance.

Implementation Method 1

an intermediate layer having a larger ionization potential and a smaller electron affinity than those of the first light-emitting layer and the second light-emitting layer

Methodology Applied

Scientific EffectEnergy barrier:

Data Source

PatentUS20240155858A1Light-emitting element and light-emitting device

Publication Date: 2024.05.09 SHARP KK

AI summary

A light-emitting element includes a first electrode, a second electrode, a first light-emitting layer and a second light-emitting layer provided between the first electrode and the second electrode and including the same quantum dots, and an intermediate layer provided between the first light-emitting layer and the second light-emitting layer.