A numerical study to enhance the performance of FASnI₃-based HTL-free inverted perovskite solar cell with compatible electron transport layers

Abstract Among the organic–inorganic hybrid halide perovskites used in solar applications, Formamidinium Tin Iodide (HC(NH 2 ) 2 SnI 3 ), commonly known as FASnI 3, has made remarkable progress recently because of its tunable bandgap, long-term thermal stability, substantial absorption, and high carrier mobility. Hole Transport Layer (HTL) - free inverted structure of perovskite solar cells offers better stability, simple structure, and ease of fabrication. Although simulation studies on inverted structures with FASnI 3 as an absorber layer, are available in the literature, simulations on HTL-free inverted structures are not reported. In this study, using FASnI 3 as the absorber material, the computational analysis, based on the SCAPS-1D software, investigates the performance of seven p-i-n inverted HTL-free solar cell architectures. Materials such as PCBM (Phenyl-C61-butyric acid methyl ester), WS 2 (Tungsten disulfide), C 60 (Buckminsterfullerene), CdZnS (Cadmium Zinc Sulphide), ZnOS (Zinc Oxysulphide), BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), and PEIE (Poly(ethylenimine) ethoxylated) are used as ETLs to offer proper band offset and charge collection at the interface and the study proposes the most viable candidate among them. Optimization of each cell structure is accomplished by determining the appropriate cell parameters. With PCBM, WS 2 , C 60 , CdZnS, ZnOS, BCP, and PEIE as ETL, the optimal efficiency values of the cell structure obtained are 24.77%, 30.1%, 32.06%, 31.26%, 26.43%, 21.07%, and 28.66%, in that order.