Perovskite-based solar cells are bestowed with the potential to revolutionize photovoltaic technology due to their high efficiency and low cost. Their distinct crystal structure enables superior charge transport and light absorption, enabling them to be a prolific substitute for conventional silicon-based solar cells, and further study is intended to increase their stability and scalability. The Study aims to increase efficiency by optimizing the absorber layer thickness with a gold/Methyl ammonium Tin Iodide/Titanium dioxide/Gallium doped zinc oxide (Au/CH3NH3SnI3/TiO2/ZnO:Ga) cell construction. The solar cell capacitance simulator-1D (SCAPS-1D) has been used to simulate the structure of perovskite solar cells. We have investigated the impact of absorber layer thickness on cell efficiency using the software tool. With an open circuit voltage (Voc) of 0.847 V, a short-circuit current density (Jsc) of 32.86mA/cm2, and a fill factor (FF) of 74.56%, the cell's conversion efficiency (eff) was 20.18%. The findings showed that hole transport materials (HTM) and lead-free perovskite solar cells are promising substitutes for conventional solar cells in the days to come.