Numerical simulations of 22% efficient all-perovskite tandem solar cell utilizing lead-free and low lead content halide perovskites

Abstract

Lead-free or low lead content perovskite materials are explored in photovoltaic (PV) devices to mitigate the challenges of toxic lead-based halides. However, the conversion efficiency from such materials is far below compared to its counterparts. Therefore, to make a humble contribution in the development of lead-free or low lead content perovskite solar cells (PSCs) for future thin-film PV technology, a simulation study of tin (Sn) and Pb mixed halide (MAPb0.5Sn0.5I3, 1.22 eV) PSC is carried out in this manuscript. The device is further optimized in terms of transport layer and thickness variation to get 15.1% conversion efficiency. Moreover, the optimized narrow bandgap halide based device is further deployed in the monolithic tandem configuration with lead-free wide bandgap (1.82 eV) halide, i.e. Cs2AgBi0.75Sb0.25Br6, 1.82 eV (WBH) PSC, to mitigate the thermalization as well as transparent E g losses. Filtered spectrum, current matching, and construction of tandem J–V curve at the current matching point are utilized to design the tandem solar cell under consideration. Tandem device delivered short current density, J SC (15.21 mA cm−2), open-circuit voltage, V OC (1.95 V), fill factor, FF (74.09%) and power conversion efficiency, PCE (21.97%). The performance of the devices considered in this work is found to be in good approximation with experimental work.