Limitations and design considerations for donor–acceptor systems in luminescent solar concentrators: the effect of coupling-induced red-edge absorption

Abstract

Luminescent solar concentrators (LSCs) use luminescence and waveguiding to concentrate photons within thin dielectric slabs for use in photovoltaic, lighting, and photobioreactor applications. Donor–acceptor systems of organic chromophores are widely used in LSCs to broaden the sunlight absorption range and attempt to reduce loss-inducing reabsorption by the emitting chromophore. We use raytrace simulations across a large parameter space to model the performance of LSCs containing two novel donor–acceptor trimers based on the perylene moiety. We find that under certain conditions, trimers outperform single-dye LSCs as expected. However, at higher concentrations, a slight increase in red-edge absorption by the trimers increases reabsorption and has a deleterious effect on LSC performance. This underscores the large effect that even small changes in the red edge can have, and may discourage the use of donor–acceptor schemes with high interchromophore coupling that promotes red-edge absorption. Finally, we show that for a LSC-PV pair, selecting a PV cell that is well-matched with the LSC emission spectrum has a large effect on the flux gain of the system, and that the systems studied here are well-matched to emerging PV technologies.

Simple and Robust Panchromatic Light Harvesting Antenna Composites via FRET Engineering in Solid State Host Matrices

“…The LSC ray trace model was constructed in Matlab and has been previously reported. , LSC geometry was modeled as a square planar slab with a depth of 0.3 cm. The side length and dye concentration could be varied.…”

“…Previously this could only be achieved in heavily doped thin film LSCs. ,, This dense packing of chromophores can be avoided by linking donor and acceptor chromophores covalently together. ,,, The most well-known examples of covalent energy transfer systems involve dendrimers that are substituted with a number of chromophores creating an intermolecular energy gradient. This allows the system to achieve large Stoke-shifts with maximum solar absorption; however, PLQYs are relatively low and the molecules are synthetically complex to fabricate. ,− Also, care is required when designing such systems as any increase in red edge absorption compared to the single chromophore units can reduce performance at large scale …”

“…5,51−53 Also, care is required when designing such systems as any increase in red edge absorption compared to the single chromophore units can reduce performance at large scale. 54 Covalently linking chromophores solves the problem of chromophore aggregation but adds synthetic complexity and reduced PLQYs limit their potential. Achieving high local concentrations of chromophores, to enable FRET, while maintaining high PLQY and limiting aggregation in a simple manner is still an unsolved problem.…”

Emissive Molecular Aggregates and Energy Migration in Luminescent Solar Concentrators

“…In addition, the distance dependent IPCE data for the energy migration LSC showed reduced reabsorption when compared to the optically thick LR305 LSC (Figure h). An alternative strategy to the stochastic energy migration approach is to covalently link donor and acceptor chromophores to form arrays. , This approach allows for efficient energy transfer between donors and to the acceptor without the need for diffusive energy transport, but does require careful design of the chromophore array at higher synthesis cost.…”

Star-shaped fluorene–BODIPY oligomers: versatile donor–acceptor systems for luminescent solar concentrators

“…The LSC raytrace model was constructed in Matlab and has been previously reported. 70 LSC geometry was modelled as a square planar slab with a depth of 0.3 cm. The side length and dye concentration could be varied.…”