Performance analysis and eco-friendly design of all-inorganic 2D/3D multi-junction perovskite tandem solar cells with 28.15% efficiency

Abstract Multi-junction tandem solar cells hold great potential as advanced photovoltaic devices for achieving superior solar energy conversion efficiency. In this study, we leverage device simulation techniques to thoroughly investigate the performance of a lead-free all-inorganic perovskite tandem solar cell. Our proposed device incorporates a two-dimensional perovskite absorber in the top cell (ITO/WS 2 /Cs 3 Bi 2 I 9 /Cu 2 O) and a three-dimensional perovskite absorber in the bottom cell (ITO/WS 2 /RbGeI 3 /Cu 2 O/Au). This design strategy is meticulously tailored to ensure optimal light absorption across the visible solar spectrum. By utilizing a standard AM 1.5G spectrum and a filtered spectrum for the top and bottom cells, respectively, coupled with thickness optimization to achieve current matching conditions, we propose a champion tandem structure. Notably, the champion tandem cell, featuring top and bottom cell thicknesses of 900 nm and 263 nm, respectively, exhibits improved performance metrics: a power conversion efficiency of 28.15%, a fill factor of 88.67%, a short-circuit current density of 14.30 mA cm −2 , and an open-circuit voltage of 2.22 V. The obtained results indicate a significant advancement in enhancing the efficiency of eco-friendly perovskite solar cells.