Design and simulation of high efficiency KSnI₃ based perovskite solar cells using DFT and SCAPS-1D

This study presents a novel KSnI₃-based heterostructure solar cell design, incorporating efficient electron transport layers (ETLs) such as CeO₂, and hole transport layers (HTLs) based on CBTS. Using Density Functional Theory (DFT), the electrical and optical properties of KSnI₃ are characterized and implemented in SCAPS-1D to model the proposed solar cell. The numerical analysis demonstrates that the ITO/CeO₂/KSnI₃/CBTS/Ag structure achieves significant photo-conversion efficiency. Key factors such as KSnI₃ layer thickness, series resistance, light conversion efficiency, and operating temperature are investigated to optimize performance. Additionally, the influence of ETL and absorber thickness, defect density, and electron affinity are examined. The simulation results show strong agreement with both numerical and experimental data, yielding an optimized open-circuit voltage (V_OC) of 0.86 V, a short-circuit current density (J_SC) of 21.5 mA/cm², a fill factor (FF) of 86.05%, and an enhanced power conversion efficiency (PCE) that increased from 11.3 to 13.46% at a KSnI₃ thickness of 1.4 μm, under a defect density of 10¹⁴ cm^-3 and an electron affinity of 3.44 eV. This comprehensive simulation offers valuable insights that can guide further research on KSnI₃-based solar cells.