LED Mixture Layer for Balanced Charge Injection
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Solution Overview
Problem
Organic light emitting diode (OLED) display devices face challenges with inefficient hole injection into the light emitting layer, leading to low light emitting luminance and a short lifespan, along with an imbalance of electrons and holes.
Innovation Solution
A light emitting diode and display device design incorporating a mixture layer with quantum dots, hole transporting materials, and electron transporting materials, where the hole transporting material and electron transporting material surround the quantum dot, forming a single layer to facilitate balanced injection of holes and electrons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional OLED structure with separate hole transporting layer and light emitting layer is used, then the device structure is simple, but hole injection efficiency is low leading to low light emitting luminance and short lifespan
Solution Approach 1:
The patent combines the hole transporting layer and light emitting layer into a single mixture layer containing quantum dots, hole transporting material, and electron transporting material. This merging allows simultaneous hole transport and light emission functions in one layer, improving hole injection efficiency and light emitting performance while maintaining structural simplicity
Solution Approach 2:
The mixture layer uses a composite material system comprising quantum dots dispersed in a matrix of hole transporting material and electron transporting material. This composite structure enables multiple functions (hole transport, electron transport, and light emission) within a single layer, resolving the contradiction between structural simplicity and functional performance
2Adaptability or versatility
If separate layers for hole transport and light emission are used, then material selection is flexible, but electron-hole balance is poor leading to inefficient light emission
Solution Approach 1:
The patent merges hole transporting material, electron transporting material, and quantum dots into a single mixture layer. This allows balanced electron and hole injection to occur simultaneously at the same location, improving electron-hole balance and light emission efficiency while maintaining material selection flexibility
Solution Approach 2:
The mixture layer creates local regions where quantum dots are surrounded by both hole transporting material and electron transporting material. This local arrangement ensures that electron and hole injection occurs in close proximity to the quantum dots, improving recombination efficiency and light emission
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 design enhances the efficiency of hole and electron injection, resulting in improved light emitting efficiency and extended lifespan of the OLED display device.
Implementation Method 1
a quantum dot, a hole transporting material, and an electron transporting material... energy is outputted from the excitons to emit light
Implementation Method 2
electrons injected from one electrode and holes injected from another electrode are combined with each other in a light emitting layer
Data Source
AI summary
A light emitting diode includes a first electrode, a second electrode facing the first electrode, and a mixture layer between the first electrode and the second electrode. The mixture layer includes a quantum dot, a hole transporting material, and an electron transporting material.