<p>Lead-free perovskite materials have the potential to serve as viable alternatives to lead-based counterparts, contributing to the development of perovskite solar cells (PSCs). CsSnI₃ and CsSnCl₃ represent promising candidates for environmentally friendly PSCs, offering a compelling combination of affordability, high efficiency, and remarkable thermal stability. In this paper, four proposed PSCs were simulated using CsSnCl₃ and CsSnI₃, exploring the optoelectrical parameters of zinc oxide thin films deposited by Spray Pyrolysis Deposition (SPD) technique as an electron transfer layer (ETL) and transparent conductive oxide (TCO) on the other hand. Various organic and inorganic hole transfer materials (HTM) have been used, such as CuSCN, Spiro-MeOTAD, P3HT, PEDOT: PSS, CBTS, CuI, Cu₂O, CuO, NiO, with carbon (C) as the contact metal back. These devices were simulated using SCAPS-1D. With the best performing zinc oxide layer, adjustments were made to the absorption layer thickness and doping density of CsSnCl₃ and CsSnI₃ to improve PSC performances. The use of ZnO in PSC as TCO, in particular ZnO/CsSnCl₃/Cu₂O/C and ZnO/CsSnl₃/Cu₂O/C, achieved maximum power conversion efficiencies (PCE) of 28.15% and 30.16%, respectively. Finally, ZnO/CsSnI₃/CsSnCl₃/Cu₂O/C dual PSCs were simulated, yielding a PCE of 30.54% with a FF of 89.41%, a V_OC of 1.1499 V and a J_SC of 29.71 mA/cm². This study demonstrates that the use of zinc oxide as a TCO can lead to highly efficient perovskite devices using safe, non-toxic materials such as CsSnCl₃ and CsSnI₃.</p>