Abstract
KSnI3-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/SnO2/3CSiC/
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.