Infrared OLED Host Material Energy Transfer Optimization
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Solution Overview
Problem
Infrared emitting OLEDs suffer from low efficiency, which limits their performance in various applications.
Innovation Solution
A composition comprising a light-emitting compound with a peak wavelength of at least 650 nm, specifically a material with a group of formula (I) and an infrared emitter, is used in the light-emitting layer of OLEDs, where the host material has an excited state energy level matching or higher than the infrared emitter, enhancing energy transfer and emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional host materials are used in infrared emitting OLEDs, then the device can be manufactured with standard materials, but the external quantum efficiency and radiant power remain low
Solution Approach 1:
The patent changes the energy level parameters of the host material by selecting materials with specific excited state energy levels (≥2.1 eV) that match or exceed the infrared emitter's energy level. This parameter matching optimizes energy transfer efficiency from host to dopant, resolving the contradiction between energy loss and radiant power output
Solution Approach 2:
The patent employs composite material systems consisting of a host material (e.g., TCTA, TAPC) combined with infrared emitter dopants (e.g., Ir(ppy)3, Ru(bpy)3Cl2). This composite approach enables synergistic energy transfer while maintaining manufacturability with standard OLED materials, simultaneously improving external quantum efficiency and radiant power
2Loss of energy
If the host material's excited state energy level is increased to match or exceed the infrared emitter, then energy transfer efficiency improves, but material selection and device design become more constrained
Solution Approach 1:
The patent establishes specific energy level parameters (≥2.1 eV) as design criteria for host materials. This quantitative parameter specification provides clear guidance for material selection while ensuring optimal energy transfer, balancing efficiency requirements with material availability
Solution Approach 2:
The host material acts as an intermediary energy transfer mediator between the injected carriers and the infrared emitter dopant. By selecting host materials with appropriate energy levels (TCTA, TAPC, etc.), the system facilitates efficient energy transfer while maintaining flexibility in dopant selection across different infrared wavelengths
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 solution significantly improves the external quantum efficiency and radiant power of infrared emitting OLEDs, leading to higher light intensity and reduced drive voltage, making them more suitable for display and lighting applications.
Implementation Method 1
A light emitting layer may comprise a semiconducting host material and a light-emitting dopant wherein energy is transferred from the host material to the light-emitting dopant
Implementation Method 2
Phosphorescent dopants are also known (that is, light-emitting dopants in which light is emitted via decay of a triplet exciton)
Implementation Method 3
Holes in the highest occupied molecular orbital (HOMO) and electrons in the lowest unoccupied molecular orbital (LUMO) of a light-emitting material combine to form an exciton that releases its energy as light
Data Source
AI summary
Light-Emitting Compound A composition comprising a light-emitting compound having a peak wavelength of at least 650 nm and a material comprising a group of formula (I): wherein Ar1, Ar2 and Ar3 in each occurrence are independently selected from a C6-20 aromatic group and a 6-20 membered heteroaromatic group of C and N ring atoms and at least one of Ar1, Ar2 and Ar3 is a 6-20 membered heteroaromatic group of C and N ring atoms; x, y and z are each independently at least 1; n, m and p are each independently 0 or a positive integer; and R1, R2 and R3 in each occurrence is independently a substituent or a single bond to a polymer chain, wherein the group of formula (I) has no more than 3 single bonds to a polymer chain. The composition may be used in the light-emitting layer of an infrared organic light-emitting device.