Monolith Cs1-xRbxSnI3 perovskite – silicon 2T tandem solar cell using SCAPS-1D

Tandem solar cells (TSCs) have gained notoriety by the use of various absorber layers with different bandgaps. The photovoltaic characteristics of Cs1-xRbxSnI3 perovskite – silicon TSCs were determined through simulation using the SCAPS-1D software in this work by first validating the experimentally obtained efficiency of 2.08% for ITO/Cs0.8Rb0.2SnI3/PCBM/BCP/Al structure. The influence of chlorinated and undoped ITO front contact, variation of Electron Transport Layer (ETL) thickness, doping concentration, CBO and variation of absorber layer thickness, defect density, and doping concentration was studied. Optimum VOC (0.9893 V), JSC (30.04 mA/cm2), fill factor (81.78 %) and efficiency (24.31 %) were determined. The bottom cell was simulated independently with reference to experimental data using the structure Al/c-Si (n)/c-Si (p)/c-Si (p + )/Au resulting in an efficiency of 26.68 %. The monolithic Cs0.8Rb0.2SnI3 perovskite – silicon tandem solar cell of the architecture ITO/Cs0.8Rb0.2SnI3/c-Si (n)/c-Si (p)/c-Si (p + )/Au performance was analyzed by varying the thickness, doping concentration, and defect density of the active layers. Optimized parameters obtained were as follows: top perovskite layer thickness (100 nm), doping concentrations (5 × 1019 cm-3) and defect density (1 × 1013 cm-3), and bottom silicon absorber layer thickness (50 μm), doping concentrations (5 × 1016 cm-3), defect density (1 × 1012 cm-3), and a work function of 5.3 eV with chlorinated ITO as the front contact of the tandem cell. Optimized outcomes of efficiency (29.82 %), VOC (0.7992 V), JSC density (43.39 mA/cm2), and fill factor (85.98 %) were realized for the 2T Cs0.8Rb0.2SnI3 perovskite – silicon tandem solar cell.