Phosphorescent Light-Emitting Element with Förster Energy Transfer
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Solution Overview
Problem
Existing light-emitting elements using phosphorescent compounds face challenges in achieving high emission efficiency, particularly when multiple phosphorescent compounds with different emission colors are used, as they struggle to balance light emissions and maintain high efficiency.
Innovation Solution
The use of a combination of phosphorescent compounds with specific emission spectra, where energy transfer between the compounds is optimized through the Förster mechanism, allowing for efficient energy transfer and balanced light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple phosphorescent compounds with different emission colors are used, then the spectral balance is improved, but the emission efficiency deteriorates
Solution Approach 1:
The light-emitting layer is segmented into multiple distinct layers, each containing a different phosphorescent compound. This segmentation allows each layer to independently optimize its emission characteristics while maintaining overall spectral balance, resolving the contradiction between spectral balance and emission efficiency.
Solution Approach 2:
Each light-emitting layer is designed with specific local properties including tailored host-guest combinations, optimized dopant concentrations, and specific thicknesses to maximize the emission efficiency of each phosphorescent compound while contributing to the overall spectral balance of the device.
2Use of energy by moving object
If phosphorescent compounds are used to achieve high internal quantum efficiency, then the energy utilization is improved, but the device complexity increases
Solution Approach 1:
The device is segmented into multiple specialized layers, each handling a specific phosphorescent compound. This segmentation allows for systematic optimization of energy utilization in each layer while managing overall device complexity through modular design and standardized layer 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 high emission efficiency and a good balance of spectra, reducing power consumption and achieving low drive voltage.
Implementation Method 1
energy transfer between the compounds is optimized through the Förster mechanism, allowing for efficient energy transfer and balanced light emission
Implementation Method 2
in a compound that emits light from the triplet excited state (hereinafter, referred to as a phosphorescent compound), light emission from the triplet excited state (phosphorescence) is observed
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.