Revolutionizing environment friendly FASnI3 perovskite solar cells with pioneering selenium doped metal chalcogenide charge transport layer unlocking 32% efficiency

Due to extended thermal carrier lifespan, small bandgap, and biocompatibility, tin (Sn)-based perovskite solar cells (PSCs) have garnered attention. Sn-based PSCs (nip-type), however, have performed poorly, mostly because of the careless application of metal oxide electron transport layers (ETLs), which were first created for lead-based PSCs of the nip type. The metal oxides deeper energy levels and oxygen vacancies are too responsible for this underperformance. In order to overcome these problems, we demonstrate a metal chalcogenide ETL, namely Sn(S0.92Se0.08)2, which prevents the oxidation of Sn2+ and avoids the desorption of oxygen molecules. The variation of several charge transport layers is thoroughly analyzed in this work, indicating that SnS2, TiO2, and metal-doped Sn(S0.92Se0.08)2 are viable options to improve the efficiency of the FASnI3 (Energy gap (Eg) ≈ 1.41electron volt (eV) PSC. With Sn(S0.92Se0.08)2 as ETL and PTAA as Hole transport layer (HTL), the PSC's performance is maximized and the optimal performance device structure is attained. For our investigation, the optimal device structure is (Au/PTAA/FASnI3/Sn(S0.92Se0.08)2/FTO). We obtain an outstanding optimized value of Power conversion efficiency (PCE) 32.22%, Open circuit voltage (VOC) 1.2762 V, Fill factor (FF) 81.87%, and Short-circuit current density (JSC) 30.836 mA.cm- 2 by carefully evaluating and optimizing a number of variables, such as thickness of active layer, ETL and HTL, Acceptor density (NA), Defect density (Nt) vs. thickness variation, Interface defect (IDD) and temperature variation. These findings provide a viable pathway for enhancing the efficiency of Sn-based PSCs.