Performance evaluation of lead–free double-perovskite solar cell

This article presents the numerical simulation of lead–free (Pb-free) double–perovskite (Cs2AgBi0.75Sb0.25Br6, i.e., mixed antimony bismuth halide double-perovskite) solar cell (DPSC) using solar cell capacitance one dimensional simulator (SCAPS-1D). In this contribution, the hole transport layers (HTLs) and electron transport layers (ETLs) are optimized. The optimization is performed by correlating the open circuit voltage (VOC) with the built-in potential (Vbi). It is disclosed from the simulation results, that higher Vbi resulted higher VOC. Furthermore, it is also found that, for the proper selection of HTL, the EV_HTL (Valence band maximum of HTL) and φBC (Work function of back contact) should not be much deeper than the EV_PVK (Valence band maximum of double–perovskite layer) to avoid Vbi loss. Correspondingly, for proper selection of ETL, EC_ETL (Conduction band minimum of electron transport layer) and ΦFC (Work function of front contact), should not be much higher than EC_PVK to prevent Vbi loss. The optimized HTL and ETL are found to be Cu2O (copper(I) oxide) and ZnOS (Zinc oxysulfide) respectively. Moreover, the device photovoltaic performance is further improved by optimizing the double-perovskite layer thickness which is found to be 400 nm. Under optimized condition, the device photovoltaic power conversion efficiency (η) improves to 18.18%. The optimized device photovoltaic performance are found to be, open –circuit voltage (Voc) = 1.39 V, short-circuit current density (JSC) = 16.04 mA/cm2, and fill factor (FF) = 78.34% which indicates that double–perovskite absorber layer (Cs2AgBi0.75Sb0.25Br6) is a suitable candidate for the development of highly efficient Pb-free DPSC.