Phosphorescent Light-Emitting Layer Stacking for Balanced Color Output
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Solution Overview
Problem
Current light-emitting elements using phosphorescent compounds face challenges in achieving high emission efficiency, especially when multiple dopants with different emission colors are used, as they struggle to balance light emissions and maintain high efficiency simultaneously.
Innovation Solution
The implementation of a light-emitting element structure that employs Förster energy transfer between phosphorescent compounds, where each compound is dispersed in a host material, allowing efficient energy transfer and optimized layer stacking to achieve balanced light emission across different colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If phosphorescent compounds with different emission colors are used as dopants, then color rendering properties are improved, but emission efficiency deteriorates
Solution Approach 1:
The light-emitting layer is divided into multiple sub-layers, each containing a specific phosphorescent dopant compound for different emission colors (blue, green, red). This segmentation allows each sub-layer to optimize its emission characteristics independently while maintaining overall high efficiency through controlled energy transfer between layers.
Solution Approach 2:
Host materials serve as intermediaries between the phosphorescent dopant compounds and the electrodes. These host materials facilitate efficient energy transfer to the dopants while managing carrier injection and recombination, enabling balanced light emission across different colors without sacrificing overall emission efficiency.
2Ease of manufacture
If multiple phosphorescent dopants are used, then light emission balance across colors is improved, but device complexity increases
Solution Approach 1:
The light-emitting layer is segmented into multiple sub-layers, each containing a specific phosphorescent dopant compound for different emission colors (blue, green, red). This segmentation allows each sub-layer to optimize its emission characteristics independently while maintaining overall high efficiency through controlled energy transfer between layers.
Solution Approach 2:
The concentration ratios of phosphorescent dopant compounds in different sub-layers are precisely controlled (e.g., blue: 0.01-10 wt%, green: 0.01-10 wt%, red: 0.01-10 wt%) to achieve balanced color emission. By adjusting these parameters, the device achieves color balance without requiring complex additional structures.
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 approach results in a light-emitting element with enhanced emission efficiency and reduced power consumption, achieving a high balance of light emissions and improved color rendering properties.
Implementation Method 1
The implementation of a light-emitting element structure that employs Förster energy transfer between phosphorescent compounds
Implementation Method 2
luminescence from the triplet excited state (T*) is referred to as phosphorescence
Implementation Method 3
light-emitting elements utilizing electroluminescence (EL)
Data Source
AI summary
An object is to provide a light-emitting element which uses a plurality of kinds of light-emitting dopants and has high emission efficiency. In one embodiment of the present invention, a light-emitting device, a light-emitting module, a light-emitting display device, an electronic device, and a lighting device each having reduced power consumption by using the above light-emitting element are provided. Attention is paid to Förster mechanism, which is one of mechanisms of intermolecular energy transfer. Efficient energy transfer by Förster mechanism is achieved by making an emission wavelength of a molecule which donates energy overlap with a local maximum peak on the longest wavelength side of a graph obtained by multiplying an absorption spectrum of a molecule which receives energy by a wavelength raised to the fourth power.