Quantum Dot Light-Emitting Element With Dual-Density Layers

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Solution Overview

Problem

Foreign matters such as moisture or air entering a light-emitting layer with quantum dots lead to deterioration, reducing luminous efficiency and increasing the required voltage, while reducing quantum dot density impedes carrier transport.

Innovation Solution

A light-emitting element with a layered light-emitting layer structure, where one region has a lower quantum dot density and is filled with an inorganic matrix, protecting the dots from oxidation and facilitating current injection in another region.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the density of quantum dots in the light-emitting layer is reduced to prevent foreign matter propagation, then the protection against foreign matters is improved, but the carrier transport capability deteriorates and luminous efficiency decreases

Engineering Contradiction:

Improveprotection against foreign matter propagationVSAvoidluminous efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The light-emitting layer is divided into two distinct regions: a first light-emitting layer with high quantum dot density for efficient carrier transport and light emission, and a second light-emitting layer with low quantum dot density for protecting against foreign matter propagation. This segmentation allows each region to perform its specialized function optimally without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the light-emitting layer are assigned different quantum dot densities according to their specific functional requirements. The first region has high density for efficient carrier transport, while the second region has low density for foreign matter protection. This local differentiation resolves the contradiction by allowing each area to have the properties it needs.

Inventive Principle:

Principle #3Local quality

2Reliability

If the density of quantum dots is reduced to prevent foreign matter deterioration, then the reliability is improved, but the voltage required for obtaining predetermined luminance increases

Engineering Contradiction:

Improveresistance to foreign matter deteriorationVSAvoidvoltage requirement

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The light-emitting layer is segmented into two functional zones: the first light-emitting layer with high quantum dot density that maintains efficient carrier transport and low voltage operation, and the second light-emitting layer with low quantum dot density that provides protection against foreign matter deterioration. This segmentation allows the device to achieve both low voltage operation and high reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different quantum dot densities to different regions based on their functional needs. The high-density first region ensures efficient carrier transport and low voltage operation, while the low-density second region provides deterioration resistance, thereby resolving the contradiction between reliability and voltage requirement.

Inventive Principle:

Principle #3Local quality

3Loss of energy

If the density of quantum dots is increased to maintain carrier transport, then the luminous efficiency is improved, but the susceptibility to foreign matter propagation increases

Engineering Contradiction:

Improveluminous efficiencyVSAvoidsusceptibility to foreign matter propagation

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The light-emitting layer is divided into two distinct functional layers: the first light-emitting layer with high quantum dot density for efficient carrier transport and light emission, and the second light-emitting layer with low quantum dot density for protecting against foreign matter propagation. This segmentation allows the system to achieve high luminous efficiency while maintaining resistance to foreign matter effects.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions are assigned different quantum dot densities according to their functional requirements. The first region with high density optimizes carrier transport and luminous efficiency, while the second region with low density minimizes foreign matter propagation. This local differentiation resolves the contradiction between luminous efficiency and susceptibility to harmful factors.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250311530A1Light-emitting element, display device, method for manufacturing light-emitting element, and method for manufacturing display device

Publication Date: 2025.10.02 SHARP DISPLAY TECHNOLOGY CORP

AI summary

A light-emitting element includes a first electrode, a second electrode, and a light-emitting layer including a plurality of quantum dots, the light-emitting layer has a first region in which a first light-emitting layer is provided and a second region in which a second light-emitting layer is provided when viewed in a layering direction that is a direction from the first electrode to the second electrode, the density of the quantum dots in the second light-emitting layer is lower than the density of the quantum dots in the first light-emitting layer, and in the second light-emitting layer, spaces between the plurality of quantum dots are filled with an inorganic compound.