Dual-Wavelength Light-Emitting Device Using Host Material Energy Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current light-emitting devices fail to efficiently emit both near-infrared and visible light, and their reliability in doing so is limited, which hampers applications requiring simultaneous visibility and near-infrared functionality.
Innovation Solution
A light-emitting device incorporating a light-emitting organic compound and a host material in the light-emitting layer, where the emission spectrum peaks between 750 nm and 900 nm for near-infrared and 450 nm to 650 nm for visible light, with specific energy level differences and thermally activated delayed fluorescence properties to enhance emission efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the light-emitting device emits both near-infrared and visible light, then dual-wavelength functionality is achieved, but emission efficiency decreases
Solution Approach 1:
The patent assigns different local functions to different materials within the light-emitting layer: the phosphorescent material is optimized for near-infrared emission with specific triplet energy levels (2.25-2.75 eV), while the fluorescent material is optimized for visible light emission with specific singlet energy levels (2.00-2.50 eV). This local optimization of material properties ensures that each material contributes efficiently to its designated wavelength range, maintaining high overall emission efficiency while achieving dual-wavelength functionality
Solution Approach 2:
The invention carefully controls key energy level parameters: the phosphorescent material's triplet energy level (2.25-2.75 eV), the fluorescent material's singlet energy level (2.00-2.50 eV), and their energy level difference (0.20-0.50 eV). By optimizing these parameters, the system achieves efficient energy transfer and simultaneous emission at both wavelengths without excessive energy loss
2Illumination intensity
If visible light emission is enhanced for visibility, then visibility improves, but near-infrared emission efficiency decreases
Solution Approach 1:
The patent uses the host material as an intermediary that facilitates energy transfer between the phosphorescent and fluorescent materials. The host material has a triplet energy level of 2.10-2.60 eV, which is lower than the phosphorescent material's triplet energy level but higher than the fluorescent material's singlet energy level. This intermediary energy level structure enables efficient energy transfer from the phosphorescent material to the fluorescent material, allowing visible light emission enhancement without compromising near-infrared emission efficiency
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 device achieves efficient emission of both near-infrared and visible light, improving reliability and visibility, particularly in applications like authentication, analysis, and diagnosis, while minimizing visible light interference with near-infrared operations.
Implementation Method 1
An example of the light-emitting organic compound is a compound capable of converting a triplet excited state into light (also referred to as a phosphorescent compound or a phosphorescent material)
Implementation Method 2
The host material preferably exhibits thermally activated delayed fluorescence
Data Source
AI summary
A light-emitting device that emits both near-infrared light and visible light is provided. The light-emitting device includes a light-emitting organic compound and a host material in a light-emitting layer. The maximum peak wavelength in an emission spectrum of the light-emitting device is greater than or equal to 750 nm and less than or equal to 900 nm, the energy of the maximum peak in the emission spectrum of the host material is higher than the energy of a peak of a lowest-energy-side absorption band in an absorption spectrum of the light-emitting organic compound. The light-emitting device has a function of emitting both visible light and near-infrared light.