Solar cells offer a simpler method of utilizing the abundant renewable energy source. The most potential substitute for silicon solar cells, perovskite solar cells (PSCs), have advanced quickly in recent years. The Solar Cell Capacitance Simulator (SCAPS)-1D was used in this paper to suggest low-cost charge selective materials, such as ETM and HTM, that may produce good photovoltaic performance. To investigate the properties of CH3NH3PbI3-based solar cells with various HTM layers, such as Cu2O and ETM layers, such as SnO2, TiO2, and ZnO, respectively. Additionally, the thicknesses of the perovskite absorber are adjusted to obtain the highest photovoltaic efficiency, and the impact of the defect at the perovskite absorber layer on solar cell performance is also investigated. From this paper it has been investigated that, the thickness of the absorber layer, and defect density in a perovskite solar cell had a substantial impact on JSC, FF, VOC, and efficiency. The findings show a significant gain in efficiency (18%) when the ETM layer is ZnO. When the defect density of the perovskite layer rises, the JSC, VOC, FF, and PCE values of perovskite solar cells dramatically drop. According to our findings, the ZnO ETM is the most likely to provide a high photovoltaic (PV) efficiency when combined with Cu2O based HTM.