Enhancing optical efficiency of thin-film luminescent solar concentrators by combining energy transfer and stacked design

We report on a new approach aimed at enhancing the optical efficiency of luminescent solar concentrators (LSCs) based on poly(methyl methacrylate) (PMMA) thin-films doped with highly emissive fluorophores. In detail, a series of high-energy absorbing fluorophores (HEF) and perylene bisimides (PBI) red-emitting dyes were utilized in order to favor the collection of a large number of incident photons by the thin-film LSCs. The use of two fluorescent PMMA layers coated on the opposite surfaces of a glass slab was found to effectively increase the light concentration. The worthwhile combination of the appropriate HEF and PBI fluorophores within the secondary (bottom) PMMA layer assured optically efficiencies 10-14% greater than the maximum value of single-dye LSCs.