Investigating impact of electron transport layer engineering in performance enhancement of CH 3 NH 3 SiI 3 based perovskite solar cells

Abstract The potential of methyl ammonium silicon triiodide (CH₃NH₃SiI₃) is garnered a lot of attention in the past for its contribution towards stability of a solar cell. However, its power conversion efficiency (PCE) still needs to be explored to full potential. In this work, the silicon based perovskite solar cell is investigated systematically from the electron transport layer (ETL) perspective through the Solar Cell Capacitance Simulator (SCAPS-1D). The proposed solar stack is Ag/PCBM/CH₃NH₃SiI₃/PEDOT: PSS/Au, where PEDOT: PSS acts as the hole transport layer (HTL) and PCBM (phenyl-C₆₁-butyric acid methyl ester) serves as the electron transport layer (ETL). Amongst, several ETL, PCBM emerged as the most suitable ETL material owing to its perfect band alignment with the absorber layer. The proposed device is investigated by optimizing the doping concentration, absorber layer thickness, defect density, operating temperature and followed by analysis of generationrecombination profile. In addition to it, specifically the optoelectronic properties of PCBM as ETL were systematically analysed, compared with others and optimized to enhance much needed PCE. The simulation results shows an open-circuit voltage (Voc,) of 1.33 V, shortcircuit current density (Jsc) of 27.46 mA/cm 2 and fill factor (FF) of 87.5% with a remarkable power conversion efficiency(PCE) of 32.19%. The findings of this investigation exhibits the potential of methyl ammonium silicon triiodide as a viable option of lead-free perovskite material for next-generation photovoltaic devices and reveals the key role of ETL selection and optimization in achieving high power conversion efficiency and overall device performance.