Kheswa, Bonginkosi VincentMajola, Siyabonga Ntokozo ThandoluhleAl-Dmour, HmoudNdzane, Nolufefe MurielMakhathini, Lucky2026-05-192026-05-192025Kheswa, B.V., Majola, S.N.T., Al-Dmour, H., Ndzane, N.M. and Makhathini, L., 2025. Modeling and Analysis of KSnI3 Perovskite Solar Cells Yielding Power Conversion Efficiency of 30.21%. Nanomaterials, 15(8), p.580.https://doi.org/10.3390/nano15080580https://hdl.handle.net/10566/22669KSnI3-based perovskite solar cells have attracted a lot of research interest due their unique electronic, optical, and thermal properties. In this study, we optimized the performance of various lead-free perovskite solar cell structures—specifically, FTO/Al–ZnO/KSnI3/rGO/Se, FTO/LiTiO2/KSnI3/rGO/Se, FTO/ZnO/KSnI3/rGO/Se, and FTO/SnO2/KSnI3/rGO/Se, using the SCAPS-1D simulation tool. The optimization focused on the thicknesses and dopant densities of the rGO, KSnI3, Al–ZnO, LiTiO2, ZnO, and SnO2 layers, the thickness of the FTO electrode, as well as the defect density of KSnI3. This yielded PCE values of 27.60%, 24.94%, 27.62%, and 30.21% for the FTO/Al–ZnO/KSnI3/rGO/Se, FTO/LiTiO2/KSnI3/rGO/Se, FTO/ZnO/KSnI3/rGO/Se, and FTO/SnO2/KSnI3/rGO/Se perovskite solar cell configurations, respectively. The FTO/SnO2/KSnI3/rGO/Se device is 7.43% more efficient than the FTO/SnO2/3C-SiC/KSnI3/NiO/C device, which is currently the highest performing KSnI3-based perovskite solar cell in the literature. Thus, our FTO/SnO2/KSnI3/rGO/Se perovskite solar cell structure is now, by far, the most efficient PSC design. Its best performance is achieved under ideal conditions of a series resistance of 0.5 Ω cm2, a shunt resistance of 107 Ω cm2, and a temperature of 371 K.enKSnI3PerovskiterGOSnO2SolarArticle