Hybrid Perovskite Thin Films as Highly Efficient Luminescent Solar Concentrators

Organic-inorganic hybrid perovskite (PVSK) compounds are at the forefront of photovoltaic research, consistently surpassing silicon solar cells in power conversion efficiency. Possessing high refractive index, broad absorption spectrum, and superior quantum yields, hybrid PVSK thin films are theoretically also ideal candidates for luminescent solar concentrators (LSCs). In practice, however, the possibility of high self-absorption in a continuous film, coupled with the inherent instability of PVSK materials, have hindered their use in this context. In this work, the viability of hybrid PVSK thin films as the active medium in planar LSCs is investigated. Using spectroscopic and photovoltaic measurements, variation of optical stability and device performance with different lead sources in the PVSK film precursors are monitored. The results display high optical efficiency in the range 15%-29% despite high self-absorption losses, and the devices remain operational even after seven weeks in ambient conditions. Confirmed by Monte Carlo simulations, the superior performance is attributed to the high quantum yield and refractive index of the PVSKs. These results are encouraging not only for the implementation of PVSK thin films in LSCs, but additionally, for preparation of tandem devices to capture energy escaping as radiative exciton recombination in PVSK solar cells.