Luminescent Solar Collectors: Quo Vadis?

Luminescent solar concentrators (LSCs) are optical systems that absorb, convert, and concentrate solar light by means of photoluminescence of an emitting material embedded in a transparent waveguide. LSCs combine large possibilities of variation of shape, flexibility, color, and transparency and can operate under direct or diffuse light. LSCs were actively investigated in the period 1975-1985 in view of photovoltaic (PV) conversion. After 20 years of sleep, research on LSCs has reemerged in the first years of the millennium driven by their potential application for PV conversion in built environment. Research on LSCs aims at the development of new active and passive components, namely emitting and light-guiding materials, and at the reduction of the loss factors associated with the elemental processed involved in the operation in order to improve power conversion efficiency. After a brief historical account, the operating principles, characterization, components, technology, and applications are reviewed. Finally, the performance of LSCs are critically discussed in a global perspective with particular emphasis on the basic contradiction between light concentration and conversion efficiency leading to some suggestions for future development of the topic.