Lead-free perovskites are considered a substitute for solar cell applications due to their favorable optoelectronic characteristics, environmental stability, and low toxicity. Moreover, cesium hexabromopalladate (IV) (Cs2PdBr6) is a promising and competitive absorber material for lead-free nontoxic perovskite solar cells (PSCs). This is the first ever reported work on the simulation of Cs2PdBr6 based solar cell using Solar Cell Capacitance Simulator (SCAPS -1D) software. In this work, two device structures with a configuration of FTO/TiO2/Cs2PdBr6/MoO3/Au and FTO/C60/Cs2PdBr6/MoO3/Au were proposed. The two electron transport layers (ETLs), i.e., titanium dioxide (TiO2) and buckminsterfullerene (C60) with lead-free double PSC, were compared, achieving power conversion efficiencies (PCEs) of 23.98 and 21.81%, respectively. During this simulation, MoO3 was used as a hole transport layer (HTL), fluorine-doped tin oxide (FTO) as a front contact, Cs2PdBr6 as an absorber layer, and Au as a back contact. On the basis of the obtained results, TiO2 can be identified as the optimal ETL for Cs2PdBr6, achieving power conversion efficiency (PCE) of 26.0%, whereas for C60 ETL, the optimized PCE was 23.36%. The results were obtained through optimization of various parameters, including thickness, temperature, back contact, series resistance, and shunt resistance. The integration of TiO2 with Cs2PdBr6 in the proposed solar cell yielded promising results, i.e., VOC = 1.3142 V, PCE = 26.00%, FF = 89.55%, and JSC = 20.093 mA/cm2, demonstrating an improved performance. The proposed solar cell is also considered an excellent lead-free material for developing effective PSCs for solar applications.
