Performance evaluation of lead–free double-perovskite solar cell

Abstract

This article presents the numerical simulation of lead–free (Pb-free) double–perovskite (Cs 2 AgBi 0.75 Sb 0.25 Br 6 , 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 (V OC ) with the built-in potential (V bi ). It is disclosed from the simulation results, that higher V bi resulted higher V OC . Furthermore, it is also found that, for the proper selection of HTL, the E V_HTL (Valence band maximum of HTL) and φ BC (Work function of back contact) should not be much deeper than the E V_PVK (Valence band maximum of double–perovskite layer) to avoid V bi loss. Correspondingly, for proper selection of ETL, E C_ETL (Conduction band minimum of electron transport layer) and Φ FC (Work function of front contact), should not be much higher than E C_PVK to prevent V bi loss. The optimized HTL and ETL are found to be Cu 2 O (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 (J SC ) = 16.04 mA/cm 2 , and fill factor (FF) = 78.34% which indicates that double–perovskite absorber layer (Cs 2 AgBi 0.75 Sb 0.25 Br 6 ) is a suitable candidate for the development of highly efficient Pb-free DPSC. • The numerical simulation of lead-free double–perovskite is performed with-optimized device efficiency of 18.18%. • The electron transport layer and hole transport layer is optimized by co-orelating V OC with V bi . • The simulation study reveals that V OC is strongly dependent on V bi of lead-free double –perovskite absorber layer. • The optimized ETL and HTL found to be ZnOS and Cu 2 O respectively.