The results of a specific modelling technique for perovskite (PVK)-based solar cells under preconditioned AM1.5 illumination for various device architectures are presented in this work. The widely used PVK material of MAPbI3 has certain architectural issues, such as volatility and instability due to the presence of methylammonium (MA). To deal with such issues, replacing MA with Cesium can provide a stable PSC device. The primary goal of this research is to optimize the thickness parameters of the methylammonium-free PVK active layer, i.e., Caseium lead iodide (CsPbI3) and the carrier transport layers (CTLs). The current simulation uses TiO2 and Spiro-OMeTAD as the CTLs to sandwich the CsPbI3 layer, which has a wide bandgap of 1.73 eV. Moreover, the better fabrication temperature and defectivity analysis for the perovskite solar cell are also investigated. Due to the high open-circuit voltage for the Casieum-based PSC devices offers an optimized power conversion efficiency, reaching nearly 25%, which can be beneficial for reasonable fabrication of the PSC device. © 2023, Indian Association for the Cultivation of Science.