Design and optimization of eco-friendly $${FAGeI}_{3-{\varvec{x}}}{Cl}_{{\varvec{x}}}$$ perovskite solar cells in ambient air: a comprehensive SCAPS-1D study

Abstract Highly efficient Ge-based perovskite FAGeI 3−x Cl x film is fabricated under atmospheric conditions, and characterized it by experimental studies. SEM and XRD results confirm trigonal crystal structure. FTIR analysis confirms the formation of FAGeI 3−x Cl x through bond analysis. The average value of E g is 2.02 eV and of α is >10 5 cm −1 obtain from UV–Vis analysis of the thin film. The solar cell performance is investigated by SCAPS-1D simulations. Effects of the key physical parameters such as, thickness of absorber, hole transport layers (HTLs), electron transport layers (ETLs), band gap, doping density, defect density, electron affinity, temperature, series and shunt resistance, and metal work function, etc. on device performance were optimized-to maximize device performance. The thickness of the absorber and the band gap for the simulation was taken from the analyzed data of fabricated thin film of the absorber in ambient temperature and significantly influence photovoltaic parameters more than the electron transport layers (ETLs) and hole transport layers (HTLs). This study illustrates that IGZO and CuO are optimal electron transport layer (ETL) and hole transport layer (HTL) materials, respectively, providing economical and non-toxic substitutes for conventional charge carrier transport materials while achieving high efficiency. Among back contact options, Se was identified as the most economical choice without compromising efficiency. The proposed Se/CuO(0.02)/FAGeI 3−x Cl x /CdS/IGZO(0.05)/FTO-Ag/glass device exhibits η~19.93% for as-deposited film and absorber thickness optimized device exhibits Voc = 1.426 V, J SC = 20.48 mA/cm 2 , FF = 68.39%, η=19.98% while absorber thickness and band gap optimized device demonstrates Voc = 1.293 V, J SC = 30.49 mA/cm 2 , FF = 81.21% and η = 32.01%. This study confirms that performance is directly influenced by the specified essential physical factors. Theoretical calculation demonstrates that FAGeI 3−x Cl x can produce O 2 . Therefore, these favorable characteristics signifying that FAGeI 3−x Cl x can be a potential alternative to Pb-halide perovskites for next generation efficient photovoltaic and optoelectronic devices.