Quantum Dot LED Electrode Structure Using Plasmonic Nanoparticles

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Solution Overview

Problem

Conventional quantum dot light emitting diodes suffer from low luminous and light extraction efficiencies due to refractive index mismatch and total reflection, with only about 20% of generated photons being emitted, while the remaining light is lost at different interfaces.

Innovation Solution

A light emitting diode structure comprising a first conductive layer with micropores and a second conductive layer with conductive nanoparticles, where the first conductive layer is made of aluminum and the second conductive layer is made of silver, allowing for localized surface plasmons to enhance energy transfer and reduce total reflection, improving internal quantum efficiency and light extraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional quantum dot light emitting diode structure is used, then the device is simple to manufacture, but the luminous efficiency and light extraction efficiency are low due to refractive index mismatch and total reflection

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidlight extraction efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent introduces a porous layer between the quantum dot layer and the electrode, where the porous structure with controlled pore size and distribution reduces total internal reflection by providing multiple light extraction paths. The porous material's refractive index gradient helps match the optical impedance between layers, significantly improving light extraction efficiency without complicating the manufacturing process

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent employs composite material structures combining quantum dots with specific matrix materials and interface layers. The composite design optimizes the refractive index matching between different layers while maintaining the quantum dot's luminescent properties, thereby reducing energy loss at interfaces and improving overall luminous efficiency

Inventive Principle:
Principle #40Composite materials

2Device complexity

If conventional light emitting diode structure is used, then the device structure is simple, but only about 20% of generated photons are emitted while the remaining light is lost at different interfaces

Engineering Contradiction:
Improvestructure complexityVSAvoidluminous efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent introduces additional functional layers and interface structures between the conventional LED components, creating multiple dimensions for light extraction. The porous layer and intermediate layers add optical pathways in vertical and lateral dimensions, enabling photons that would normally be trapped by total internal reflection to escape through alternative routes, thereby significantly improving luminous efficiency

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces intermediary layers between the quantum dot layer and electrode, including porous layers and refractive index matching layers. These intermediary structures serve as optical mediators that reduce the abrupt refractive index mismatch at interfaces, minimizing total internal reflection and enabling more efficient photon extraction from the active region

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 described structure significantly increases luminous intensity and light extraction efficiency, enabling a more efficient light emitting diode with improved image quality and reduced power consumption.

Implementation Method 1

A light emitting diode structure comprising a first conductive layer with micropores and a second conductive layer with conductive nanoparticles, where the first conductive layer is made of aluminum and the second conductive layer is made of silver, allowing for localized surface plasmons to enhance energy transfer and reduce total reflection

Methodology Applied
Scientific EffectLocalized surface plasmons: Resonance

Implementation Method 2

Light emitting diodes (LED) can usually be made from a compound of gallium (Ga) and arsenic (As), phosphorus (P), nitrogen (N), or indium (In), and visible light is radiated by the recombination of electrons and holes

Methodology Applied
Scientific EffectRadiative recombination: Electroluminescence

Data Source

PatentEP3699965B1Light emitting diode, manufacturing method therefor, and display apparatus
Publication Date: 2023.11.22 BOE TECHNOLOGY GROUP CO LTD
  • EP3699965B1 patent drawingFigure 1~2B
  • EP3699965B1 patent drawingFigure 2C~3
  • EP3699965B1 patent drawingFigure 4~6

AI summary

A light emitting diode, a manufacturing method thereof and a display device are provided. The light emitting diode includes a first electrode (120), an active layer (130) and a second electrode (140). The active layer (130) is on the first electrode (120); the second electrode (140) is on a side of the active layer (130) away from the first electrode (120), and includes a first conductive layer (141) and a second conductive layer (142) sequentially arranged along a direction away from the active layer (130); the first conductive layer (141) includes a plurality of micropores (1410); and the second conductive layer (142) includes a plurality of conductive nanoparticles (1420). Therefore, luminous efficiency and light extraction efficiency of the light emitting diode can be improved through localized surface plasmons generated by the second conductive layer.