Enhanced performance of lead-free tandem solar cells with CsSnCl3 perovskites: 44% power conversion efficiency

Lead-free cesium tin chloride (CsSnCl 3 ) based perovskite tandem solar cell has been simulated using solar cell capacitance simulator-1D under AM 1.5 G spectrum. In a tandem solar cell, the top cell is designed with ITO/TiO 2 /CsSnCl 3 /NiO/Au structure, while a silicon p-n junction solar cell is taken at the bottom. The effect of absorber layer thickness, variation in total defect density, and its effect on output parameters are measured. In a standalone cell, the optimized CsSnCl 3 thickness of 910 nm is obtained for better power conversion efficiencies (PCEs) ∼28% of the device. Further, an improved PCE of 44% has been achieved in the tandem configuration. This combination of CsSnCl 3 with silicon p-n junction can be used for higher efficiency devices that can fulfill day-to-day increasing renewable energy demands, and this lead-free material has the potential to replace already existing lead- based perovskites.