Design and simulation of CsPbI 3 /Sb 2 Se 3 tandem solar cells

Abstract Sb 2 Se 3 is an earth-abundant, non-toxic, and low-cost photovoltaic material with promising optoelectronic properties. With a direct bandgap of about 1.2 eV, Sb 2 Se 3 is well suited as the bottom cell in tandem architectures, extending spectral coverage and improving power conversion efficiency. In this study, Silvaco TCAD was employed to simulate solar cells based on inorganic CsPbI 3 (bandgap approximately 1.7 eV) and Sb 2 Se 3 . To improve the performance of Sb 2 Se 3 solar cells, the effect of MoO 3 as a hole transport layer was investigated. In the two-terminal tandem devices, we systematically investigated the effects of defect states, doping concentrations, and intermediate recombination layer thickness on the performance of the CsPbI 3 top cell and Sb 2 Se 3 bottom cell. We also examined the influence of the thicknesses of the CsPbI 3 and Sb 2 Se 3 absorber layers on the overall performance of the tandem device. Current matching can be achieved when the thickness of the CsPbI 3 layer is 259 nm and that of the Sb 2 Se 3 layer is 1000 nm. The device exhibits a current density of 17.45 mA/cm 2 , an open-circuit voltage of 2.139 V, a fill factor of 87.57%, and a power conversion efficiency of 32.66%.