LED Insulating Layer Charge Balance

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Solution Overview

Problem

Current light emitting diodes using quantum dots face challenges in achieving improved luminous efficiency and reliability, particularly in maintaining charge balance and extending the life of the device due to imbalances in hole and electron injection.

Innovation Solution

Incorporating an insulating layer, formed through atomic layer deposition or chemical vapor deposition, between the emission layer and charge transfer layers to control the injection of holes and electrons, ensuring balanced charge injection and improving the uniformity and quality of the emission layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If quantum dots are used as light emitting material to improve color reproducibility, then color quality is improved, but device reliability and lifespan deteriorate due to charge injection imbalance

Engineering Contradiction:
Improvecolor reproducibilityVSAvoiddevice reliability and lifespan
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

An insulating layer is introduced as an intermediary between the charge transfer layer and the quantum dot emission layer. This insulating layer mediates the charge injection process, preventing direct contact between the charge transfer layer and quantum dots, thereby balancing hole and electron injection while maintaining the quantum dot's light emitting properties and improving device reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulating layer changes the electrical parameters at the interface between charge transfer layer and emission layer, creating an optimized charge injection environment that balances hole and electron injection into the quantum dots, thus improving both reliability and maintaining color quality

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional manufacturing processes are used, then manufacturing simplicity is maintained, but insulating layer quality and uniformity deteriorate

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidinsulating layer quality and uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Conventional spin-coating or dip-coating mechanical deposition methods are replaced with Chemical Vapor Deposition (CVD) or Atomic Layer Deposition (ALD) processes. These vapor-phase deposition techniques provide superior conformal coverage, uniform thickness control, and higher quality insulating layers compared to mechanical coating methods

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The deposition method changes from liquid-phase mechanical coating to vapor-phase chemical deposition, fundamentally changing the physical and chemical parameters of the deposition process to achieve superior insulating layer quality, uniformity, and coverage

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 solution enhances the light emission properties, stability, and lifespan of the light emitting diode by maintaining balanced charge injection, thereby improving luminous efficiency and reliability.

Implementation Method 1

Incorporating an insulating layer, formed through atomic layer deposition or chemical vapor deposition

Methodology Applied
Scientific EffectAtomic layer deposition:

Implementation Method 2

Incorporating an insulating layer, formed through atomic layer deposition or chemical vapor deposition

Methodology Applied
Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentEP3716349B1Light emitting diode, manufacturing method thereof and display device including the same
Publication Date: 2025.01.01 SAMSUNG DISPLAY CO LTD
  • EP3716349B1 patent drawingFigure 1~2
  • EP3716349B1 patent drawingFigure 3A~3B
  • EP3716349B1 patent drawingFigure 4~5

AI summary

A light emitting diode according to embodiments of the present disclosure includes a first electrode, a second electrode opposite the first electrode, an emission layer between the first electrode and the second electrode, the emission layer including a quantum dot, a first charge transfer layer between the first electrode and the emission layer, a second charge transfer layer between the second electrode and the emission layer, and an insulating layer in at least one position between the first charge transfer layer and the emission layer, and/or between the second charge transfer layer and the emission layer, wherein the insulating layer includes an inorganic material. The light emitting diode and a display device including the same show improved life characteristics and emission efficiency properties.