Light Harvesting Array Reduces Reabsorption Losses
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Solution Overview
Problem
Existing light harvesting systems face inefficiencies due to reabsorption losses caused by overlapping absorption and emission bands of fluorophores, leading to reduced light harvesting efficiency, particularly in solid-state devices and solutions.
Innovation Solution
A light harvesting array comprising an acceptor linked to a donor, where at least one of the acceptor or donor is an oligomeric unit, such as a rylene-based structure, capable of energy transfer through FRET or other processes, designed to minimize reabsorption losses by decoupling the absorbance and fluorescence wavelengths, thereby enhancing quantum yield and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the concentration of fluorophore is increased to harvest more light, then the amount of light harvested increases, but reabsorption losses increase proportionally
Solution Approach 1:
The patent changes the spectral parameters of the fluorophore by using oligomeric units with progressively red-shifted absorption and emission bands. This parameter change allows the emission spectrum of one oligomer to overlap with the absorption spectrum of another, enabling energy transfer while minimizing reabsorption losses at the same wavelength
Solution Approach 2:
The patent introduces an intermediary energy transfer mechanism where oligomeric units act as intermediate carriers. Energy is transferred from higher energy oligomers to lower energy oligomers or acceptors through spectral overlap, serving as an intermediary step that avoids direct reabsorption losses
2Loss of energy
If oligomeric units are used to reduce reabsorption losses, then energy transfer efficiency improves, but device complexity increases
Solution Approach 1:
The patent segments the light harvesting function into multiple oligomeric units with different absorption and emission characteristics. Each oligomer handles a specific spectral region, and they are arranged in energy cascades to transfer energy systematically, dividing the complex function into manageable segments
Solution Approach 2:
The patent uses composite oligomeric structures combining different rylene units (e.g., perylene, terrylene, quarterrylene) with distinct spectral properties. These composite materials work together in energy transfer cascades, achieving high efficiency while managing complexity through functional integration
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 light harvesting array achieves high quantum yields and photo-stability, retaining over 60% of initial fluorescence after exposure to direct sunlight for five years, with energy transfer efficiencies exceeding 90%, significantly improving light harvesting efficiency compared to commercial monomeric dyes.
Implementation Method 1
Førster Resonance Energy Transfer (FRET). This term describes the process between two or more different fluorophores that are brought within close proximity to each other (typically, less than 10−9 meters) to allow a radiationless (non-photonic and non-electronic) transfer of energy. This transfer flows from a fluorophore with higher energy absorption and emission bands, called the 'donor', to a chromophore with a lower energy absorption band, called the 'acceptor'
Implementation Method 2
Fluorescence is a process useful for light harvesting as it generally involves the absorption of light at one wavelength by a fluorophore, i.e. a chromophore that is capable of fluorescence, and emitting light at another wavelength, generally of a lower energy. This shift towards lower energy is called the Stokes shift
Implementation Method 3
This shift towards lower energy is called the Stokes shift, and the magnitude of the Stokes shift will depend on the properties of the fluorophore
Data Source
AI summary
The invention relates to a light harvesting array or dye comprising an acceptor linked to a donor, wherein at least one of the acceptor or the donor is an oligomeric unit comprising a first optionally substituted rylene linked via a linker group to a second optionally substituted rylene, the first optionally substituted rylene is linked to the acceptor or the donor and the second optionally substituted rylene is capable of energy transfer to at least one of the first optionally substituted rylene, the acceptor or the donor. The invention also relates to compounds which may be used as light harvesting arrays, methods for their manufacture, and devices and materials comprising the light harvesting array or dye, for example, chromophoric materials, light guides, photobioreactors, photoluminescent algae systems, photodetectors, photovoltaic devices and luminescent/fluorescent solar concentrators.