Photodegradation in multiple-dye luminescent solar concentrators

Combining multiple organic dyes to form a fluorescence resonance energy transfer (FRET) network is a useful strategy for extending the spectral range of sunlight absorbed by a luminescent solar concentrator (LSC). Excitation transfer out of the higher energy level dyes in the transfer series competes effectively with their photodegradation rates. Improvements in photostability up to a factor of 18 are observed for the first dye in the FRET series. FRET networks are shown to be a viable means of decreasing the rate of photodegradation of organic dyes used in LSCs. This comes at the expense of the final dye in the network; the depository of most of the excitations created by absorbing sunlight. The photostability and performance of an efficient FRET LSC rest heavily on the photostability and fluorescence quantum yield of the final dye. -- Highlights: • Photodegradation kinetics of multiple-dye FRET LSCs are reported. • The FRET network decreased the first dye's photodegradation rate by a factor of 18. • The final dye in the FRET LSC protects other dyes at its own expense. • The final dye must have excellent photostability and fluorescence quantum yield