Efficiency enhancement of a tandem Perovskite-Silicon solar cell

A tandem solar cell consisting of three cells is designed and simulated by the Solar Cell Capacitor Simulator (SCAPS) program. The bandgap of the top cell absorber (Cs2AgBi0.75Sb0.25Br6) is 1.8 eV, the middle cell absorber (CH3NH3PbI3) has a bandgap of 1.55 eV), and a single-crystal silicon cell (with 1.12 eV bandgap) is selected as the bottom cell. Each of these cells were simulated and optimized separately. To improve current density in the middle cell, CuSCN is chosen as the holetransport layer (HTL). Power conversion efficiencies (PCE) of individual Cs2AgBi0.75Sb0.25Br6, MAPbI3, and Si cells are 14.32%, 25.09%, and 25.22%, respectively. which are quite close to the results published in the literature. Consequently, the tandem structure of these cells is simulated and the optimal thicknesses for the absorber layers (as required by the current-matching condition) in a two-terminal (2T) monolithic structure is calculated. The optimized thicknesses of Cs2AgBi0.75Sb0.25Br6 and MAPbI3 absorber layers in the tandem configuration are 300 and 550 nm, respectively. The transmitted spectra of the top and middle cells are obtained using the Matlab software. Subsequently, the SCAPS numerical simulation for the 2T tandem structure gave an enhanced power conversion efficiency (PCEs) of 38.9%.