Design and Simulation of Novel Perovskite/Mg2Si Based Monolithic Tandem Solar Cell With 25.5% Conversion Efficiency

High thermalization losses associated with the single junction based solar cells demand the investigation of multilayer junction solar cell. Multilayer junction solar cell which comprises of top cell (high bandgap)/bottom cell (low bandgap) efficiently utilizes the solar spectrum. Perovskite/Si based tandem solar cells often require thick (>100 μm) and high quality (large lifetime) Si wafer-based bottom subcell, which eventually increases overall module cost. In this work, relatively a much thinner layer of magnesium silicide (Mg
₂
Si) of thickness 2μm is used to propose a novel perovskite/Mg
₂
Si based tandem solar cell. Proposed device exhibits open circuit voltage (V
_OC
) = 1.67 V, short circuit current density (J
_SC
) = 19.9 mA. cm
^-2
, fill factor (FF) = 76 % and power conversion efficiency (PCE) of 25.5%. The results suggest the Mg
₂
Si as an optimum choice with the band gap of 0.77 eV for the bottom cell of the tandem solar cell.