Numerical investigation and performance improvement of a lead-free WS 2 /CH 3 NH 3 SnI 3 /spiro-OMeTAD solar cell using SCAPS-1D

Abstract A lead-free perovskite solar cell based on a WS 2 /CH 3 NH 3 SnI 3 /Spiro-OMeTAD structure has been numerically designed and simulated using the SCAPS-1D tool. Thickness variations in the electron transport layer (ETL), absorber layer, and hole transport layer (HTL) have been studied and optimized to 100 nm, 500 nm, and 100 nm, respectively. The experimental absorption coefficients of the individual materials have been included to ensure realistic simulation outcomes. The device exhibits favorable band alignment that enables efficient charge separation and transport. The device has achieved impressive photovoltaic performance with a power conversion efficiency of 35.97%, a fill factor of 82.24%, a short-circuit current density of 32.47 mA cm −2 , and an open-circuit voltage of 1.34 V. The device maintains excellent stability even at a defect density of 1 × 10 11 cm −3 in the absorber layer. Temperature-dependent analysis reveals minimal efficiency degradation of 0.00579 K −1 , indicating strong thermal stability. This study highlights the WS 2 /CH 3 NH 3 SnI 3 /Spiro-OMeTAD solar cell as a highly promising candidate for advancing next-generation eco-friendly photovoltaic technologies