The power conversion efficiency (PCE) for perovskite silicon tandem solar cells is significantly higher than all other solar cell technologies. Silicon and perovskite materials are used in several applications of photovoltaics and optoelectronics. But, this research study primarily focuses on the simulation of perovskite silicon tandem solar cells to investigate the photovoltaic characteristics by utilizing a solar cell capacitance simulator (SCAPS-1D). The optimized monolithic Pero-Si tandem solar cell performance has been analyzed by varying the thickness, carrier concentration, and active layer defects. Also, interface defects were added to the structure to simulate real-life performance. Results signify that after optimizing the parameters like the thickness of top and bottom cell layers, carrier concentration and defect densities, superior outcomes of efficiency of 32.97%, the open-circuit voltage of 0.6747 (V), short circuit current density of 58.27 (mA/cm2) with a fill factor of 83.86% was achieved. Also, the effect of temperature variation on the device performance was investigated. By carefully optimizing the parameters, a greater efficiency of solar cells based on perovskite silicon tandems can be realized.