OLED Light-Emitting Layers with Charge Generation Layer
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Solution Overview
Problem
Organic light-emitting devices (OLEDs) face challenges in achieving high luminance and optimal viewing angle characteristics due to the differences in light-emitting positions and optical interference between multiple light-emitting layers.
Innovation Solution
The OLED configuration includes two light-emitting layers with different light-emitting materials, a charge generation layer with specific energy level properties, and optical interference structures to optimize light emission characteristics, such as using lenses to enhance light extraction efficiency and color purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If two light-emitting layers are provided to increase luminance, then luminance is improved, but viewing angle characteristics deteriorate due to differences in light-emitting positions and optical interference
Solution Approach 1:
A charge generation layer is introduced as an intermediary between the first and second light-emitting layers. This charge generation layer manages charge distribution between the two light-emitting layers, reducing optical interference and improving viewing angle characteristics while maintaining the high luminance benefit of having multiple light-emitting layers
Solution Approach 2:
The energy levels of the charge generation layer are specifically designed to be between the HOMO levels of the two light-emitting layers. By controlling the energy level parameters of the charge generation layer materials, the patent optimizes charge distribution and reduces optical interference, thereby improving viewing angle characteristics
2Manufacturing precision
If two light-emitting layers with different materials are used to improve light emission characteristics, then color purity is improved, but device complexity increases
Solution Approach 1:
The patent divides the light-emitting function into two separate light-emitting layers, each using different light-emitting materials optimized for specific color emission. This segmentation allows each layer to contribute to different color components, improving overall color purity while maintaining manageable device complexity through modular design
Solution Approach 2:
The patent employs composite material structures where each light-emitting layer uses different organic light-emitting materials (e.g., different fluorescent or phosphorescent materials). This composite approach enables precise control over emission spectra and color purity while managing device complexity through systematic material selection
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 configuration enhances light emission characteristics by reducing luminance loss at angles and improving viewing angle performance, achieving better color purity and light extraction efficiency.
Implementation Method 1
the charge generation layer contains an organic compound having a lowest unoccupied molecular orbital energy level lower than a highest occupied molecular orbital energy level of the second light-emitting layer
Implementation Method 2
Each of the first light-emitting material and the second light-emitting material emits light of a first color
Implementation Method 3
optical interference structures to optimize light emission characteristics, such as using lenses to enhance light extraction efficiency and color purity
Data Source
AI summary
An organic light-emitting device includes, in the following order, a first electrode, a first light-emitting layer, a charge generation layer, a second light-emitting layer, and a second electrode. The first light-emitting layer contains a first light-emitting material. The second light-emitting layer contains a second light-emitting material. Each of the first light-emitting material and the second light-emitting material emits light of a first color. The first light-emitting material and the second light-emitting material are different.