Numerical modeling of Perovskite Tandem Solar Cell with CH3NH3SnI3 Bottom Absorber

This study presents the design and analysis of a dual junction perovskite solar cell, emphasizing configurations with adjustable bandgaps and low toxicity. Utilizing SCAPS-1D software, a tandem configuration was investigated, comprising CsPbI3 (1.78 eV) as the upper cell and CH3NH3SnI3 (1.30 eV) as the lower cell. Current matching was optimized, with thicknesses of 795 nm for CH3NH3SnI3 and 380 nm for CsPbI3 in the device. Additionally, the performance of individual subcells within the configuration was optimized through tailoring the thickness of the absorber layer, and the impact temperature variation has on tandem device performance was investigated. The tandem device attained a power conversion efficiency of 34.798%, with an open-circuit voltage (Voc) of 2.4137 V, short-circuit current (Jsc) of 17.36 mA/cm², and fill factor of 83.49%. These findings highlight the potential of CH3NH3SnI3 as a high-efficiency, environmentally sustainable bottom cell absorber for dual junction solar cells.