Simulation and optimization of lead-free CH3NH3SnI3 perovskite solar cells using SCAPS-1D

Recent advances in photovoltaic technology have made perovskite solar cells attractive prospects for future energy solutions. However, the presence of lead (Pb) in many perovskite materials causes environmental and health problems, limiting their practical utility. This work investigates the possibility of lead-free perovskite solar cells (PSCs) with CH₃NH₃SnI₃ as the absorber layer. CH₃NH₃SnI₃ is chosen for its advantageous qualities such as non-toxicity, good visible light absorption, and smaller band gap. The SCAPS-1D modeling tool was used to model these cells performance in the AM 1.5 G solar spectrum. The study looks at how varying absorber layer thicknesses, doping levels, defect densities, operating temperatures, back contact materials,series and shunt resistance affect the performance of the solar cell. The simulated device structure is FTO/TiO₂/IDL/CH₃NH₃SnI₃/Carbon, with TiO₂ as the electron transport layer (ETL) and CH₃NH₃SnI₃ as the absorber layer. At 300 K, the device exhibits an open-circuit voltage (Voc) = 0.886 V, a fill factor (FF) = 81.58 %, a short-circuit current density (Jsc) = 30.68 mA/cm², and a power conversion efficiency (PCE) = 22.23 %.