Studies on the performance of FASnI₃:Zn²⁺-based lead-free perovskite solar cells: A numerical simulation

The search of stable, lead-free absorber material for perovskite solar cells (PSC) resulted in many alternatives, particularly, zinc (Zn) doped formamidinium tin iodide (FASnI₃)_. This work facilitates in investigating the behavior of four different Zn doping ratios 0 %, 2 %, 5 %, and 10 % (say Zn-0, Zn-2, Zn-5, and Zn-10) on the performance of FTO/PCBM/FASnI₃:Zn²⁺/MoO_x/Au solar cell structure. A precise evaluation on the impact of the four various Zn doping ratios in the mentioned solar structure in terms of thickness of perovskite absorber layer, hole transport layer, and electron transport layer were executed. The investigation through numerical study further deals with the role of interfacial defect density and capture cross-section of charge carriers on the performance of suggested PSCs with varying Zn doping ratios. It is evident from the optimization results that PSC having absorber layer thickness of 400 nm yields better power conversion efficiency (PCE) of 11.49 % for Zn-5. The PCE is further improved to 13.98 % for capture cross section of 2 ×10⁻¹⁵ cm². The entire work witnessed distinguishable superior behavior from FASnI₃-based PSC doped with Zn ratio: Zn-5 in comparison to the PSCs doped with other Zn ratios. Furthermore, impact of the series and shunt resistances on performance parameters are also examined.