SCAPS device simulation study of formamidinium Tin-Based perovskite solar Cells: Investigating the influence of absorber parameters and transport layers on device performance

The use of tin-based perovskite has gained popularity as an alternative to toxic lead-based perovskite in solar cells. Despite the wider absorption of the lead-free perovskite material known as CH₃NH₃SnI₃, it is prone to temperature instability, which limits its applicability. Compared to CH₃NH₃SnI₃, the absorber comprising FASnI₃ (HC(NH₂)₂SnI₃) exhibits greater temperature stability and a wider band gap of 1.41 eV. This study employs SCAPS to simulate FASnI₃-based solar cells, examining how altering the absorber parameters, including thickness, doping concentration, and defect density, affects device performance. Additionally, we investigate the influence of modifying the conduction band offset (CBO) and valence band offset (VBO), as well as the thickness and doping concentration of the electron and hole transport layers (ETL and HTL). Furthermore, the impact of interface defect density, series and shunt resistance, and the temperature dependency of the device performance are analyzed. The original design was founded on an experiment that achieved a PCE of 1.75%. However, the presented parametric study led to improvements in the intended solar cell's performance parameters. Specifically, the cell's short-circuit current density (J_SC) increased to 26.9 mA/cm², the fill factor (FF) reached 74.22 %, the open-circuit voltage (V_OC) rose to 0.907 V, and the power conversion efficiency (PCE) reached 18.11% at room temperature. Additionally, at a lower temperature of 280 K, the PCE further increased to 19.19%. The findings provide valuable insights into the efficiency, stability, and optimization of FASnI₃-based solar cells for renewable energy applications.