The quest for suitable material technology becomes an imperative aspect of PV energy conversion applications. Pursuing ideal materials or designing efficient PV devices requires a keen understanding of underlying PV action and material properties. These include defect-free, chemically and mechanically stable, semiconductive, and absorption properties, which could be easily tuned, manipulated, and readily fabricated. The candidate for such a futuristic material could be a perovskite solar cell (PSC), which has a dramatically improved performance over the last decade. [4] Recent reports observed a steep rise in efficiency from %3% to %25.5% for Pb-based hybrid perovskites (a combination of MAPbI 3 and FAPbI 3 ). [5][6][7][8] These hybrid compositions of PSC are susceptible to long-term stability issues due to temperature, moisture exposure cycle, lead (Pb)based toxicity, and I-V hysteresis characteristics, which limit or question their practical use. [9][10][11] Therefore, the significant research gap is to find practical solutions to the Pb-toxicity and stability issue while preserving or improving the inherent performance and remarkable photophysical properties. Stability issues in hybrid organic-inorganic perovskite are severe limiting issues, mainly due to hygroscopicity, volatility, and thermal and chemical instability of organic cations. It is likely resolved by replacing the organic part with inorganic-based perovskite. [12] For addressing stability issue, organic cations such as CH 3 NH 3 þ (methylammonium, MA) and (HC(NH 2 ) 2 þ (formamidium, FA) are substituted with inorganic cations such as Cs and Rb. For addressing Pb toxicity issues, Pb is substituted with same group elements Sn and Ge. [13][14][15][16][17][18] The fully inorganic perovskite are continually explored to identify suitable replacements for Pb toxicity and MA stability issues while maintaining perovskite's superior optical properties. The inorganic absorberbased devices of CsPbI 3 have shown efficiency of 20%. [19] These inorganic absorbers perform comparatively with original hybrid organic-inorganic (MAPbI 3 , FAPbI 3 ) perovskites; however, it does not answer the lead presence issue. Sn-replaced Pb perovskites have shown high absorption and optical properties, optimal bandgap, and efficiency around 10% in FASnI 3 devices. This Sn substitution solves the Pb toxicity issues; however, Sn readily goes under oxidation from Sn þ2 to Sn þ4 , which rapidly degrades device performances and further aggravates the stability issues. Literature reports have shown that partial substitution