Light-Emitting Element Potential Well for Carrier Balance

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Solution Overview

Problem

The existing light-emitting elements suffer from an imbalance in carrier distribution, with an excess of electrons injected into the light-emitting layer, leading to insufficient external quantum efficiency (EQE).

Innovation Solution

Incorporating a cathode, an anode, a light-emitting layer, an electron transport layer, and a potential well with a larger electron affinity than surrounding regions to manage electron transport and balance carriers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a composite material of hole injection material and hole transport material is used to improve hole transport capability, then hole transport capability is improved, but electron balance becomes excessive leading to insufficient external quantum efficiency

Engineering Contradiction:

Improvehole transport capabilityVSAvoidcarrier balance and external quantum efficiency

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent applies local quality by creating a potential well region with distinct electron affinity characteristics within the electron transport layer. This localized region has different electronic properties (larger electron affinity) compared to the surrounding electron transport layer, allowing it to selectively confine electrons in specific areas and prevent excessive electron injection into the light-emitting layer, thereby improving carrier balance while maintaining hole transport capability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The potential well acts as an intermediary structure between the electron transport layer and the light-emitting layer. It mediates electron transport by providing a energy barrier that controls electron flow, preventing direct excessive electron injection into the light-emitting layer while still allowing controlled electron transport, thus improving external quantum efficiency through better carrier balance.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If electron transport layer is designed to transport electrons efficiently, then electron transport capability is improved, but electron injection into light-emitting layer becomes excessive

Engineering Contradiction:

Improveelectron transport capabilityVSAvoidelectron injection quantity

Core Design Contradiction:

SpeedVSQuantity of substance

Solution Approach 1:

The electron transport layer is designed with local quality variation through the potential well region. The potential well has larger electron affinity than the surrounding electron transport layer, creating a localized electronic barrier. This allows the electron transport layer to maintain overall electron transport capability while the potential well region specifically controls electron injection quantity into the light-emitting layer by confining electrons in the well region.

Inventive Principle:

Principle #3Local quality

3Reliability

If hole injection is optimized for carrier balance, then hole transport is improved, but electron overflow occurs leading to reduced external quantum efficiency

Engineering Contradiction:

Improvecarrier balanceVSAvoidexternal quantum efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The potential well serves as an intermediary structure that decouples hole injection optimization from electron control. By introducing this intermediate potential well region with distinct electron affinity, the system can optimize hole injection for carrier balance while the potential well independently manages electron confinement, preventing electron overflow and reducing energy loss, thereby improving external quantum efficiency.

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

The solution enhances carrier balance, preventing electron overflow and improving the reliability and efficiency of the light-emitting element by reducing electron injection into the light-emitting layer.

Implementation Method 1

a potential well provided between the cathode and the light-emitting layer, and being a region having a larger electron affinity than a surrounding region

Methodology Applied

Scientific EffectElectron affinity:

Data Source

PatentUS12484374B2Light-emitting element and light-emitting device

Publication Date: 2025.11.25 SHARP KK

AI summary

A light-emitting element includes the following: a cathode; an anode; a light-emitting layer provided between the cathode and the anode; an electron transport layer provided between the cathode and the light-emitting layer; and a potential well provided between the cathode and the light-emitting layer, and being a region having a larger electron affinity than a surrounding region.