Fluorescent Infrared Emission via Host-Mediator Energy Transfer
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Solution Overview
Problem
Infrared emitting materials in organic light-emitting devices (OLEDs) have low efficiency due to a high proportion of excitons decaying non-radiatively, primarily because of their relatively small bandgap compared to visible light emitting materials.
Innovation Solution
Blending a fluorescent infrared-emitting material with a second material having a higher photoluminescent quantum yield (PLQY) and shorter peak wavelength increases the efficiency of infrared emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If infrared emitting materials are used in OLEDs, then infrared emission is achieved, but emission efficiency is low due to high proportion of non-radiative decay
Solution Approach 1:
The patent introduces a host material as an intermediary between the infrared emitter and the environment. The host material has higher energy levels and higher radiative decay probability, acting as a mediator that facilitates more efficient energy transfer and reduces non-radiative decay of the infrared emitter.
Solution Approach 2:
The patent changes the energy level parameters by selecting a host material with higher energy levels than the infrared emitter. This parameter change enables the host to transfer energy to the emitter while maintaining a higher probability of radiative decay, thereby improving overall emission efficiency.
2Use of energy by moving object
If a host material with higher energy levels is used to improve infrared emission efficiency, then radiative decay probability increases, but the system complexity increases due to material blending
Solution Approach 1:
The patent creates a composite material system consisting of the infrared emitter dissolved or dispersed in the host material. This composite approach allows the host and emitter to work together synergistically, achieving high radiative decay probability while maintaining a relatively simple two-component structure that can be processed together.
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 blending of these materials results in enhanced infrared emission efficiency, as demonstrated by increased photoluminescent quantum yield and a slight shift in peak wavelength, leading to improved performance in OLEDs.
Implementation Method 1
the second material is a fluorescent material having a higher photoluminescent quantum yield (PLQY) and shorter peak wavelength than the infrared emitting material
Data Source
AI summary
A fluorescent infrared emitting composition comprising a mixture of a first material and a second material wherein the first material is a fluorescent infrared material and the second material is a fluorescent material having a higher photoluminescent quantum yield (PLQY) and shorter peak wavelength than the infrared emitting material. The composition may be used as the light-emitting layer of an organic light-emitting device.