Harnessing Strong Band-Filling in Mixed Pb-Sn Perovskites Boosts the Performance of Concentrator-Type Photovoltaics

The need for cutting-edge solar power generation has led to the rapid development of organic-inorganic hybrid perovskites with unique photophysical properties. Photoinduced band-filling by free charge carriers, which is a consequence of the dynamic filling of the densities of states, modulates the optical transition toward high energy. Here, we observe strong band-filling in FA_0.5MA_0.5Pb_0.5Sn_0.5I₃ polycrystalline films under continuous-wave excitation, which is much more evident than that in typical MAPbI₃. Inspired by this fact, we propose novel electronic barrier adaptive concentrator-type photovoltaics, achieved by inserting an electronic barrier-inducing indene-C₆₀ bisadduct layer (ICBA). Under concentrated illumination, the potential barrier between FA_0.5MA_0.5Pb_0.5Sn_0.5I₃ and ICBA remarkably decreases, leading to a greater fill factor and a higher power conversion efficiency of 17.0% compared to that (15.6%) of the reference device. Our results provide a proof-of-concept demonstration of a novel photovoltaic system using the photophysical property of perovskites.