Numerical optimization and efficiency analysis of Sn-based perovskite-on-silicon tandem solar cells with various TCO materials using SCAPS-1D simulation

Tandem cell technology is one step forward toward sustainable energy future. In tandem cells, it is possible to harness solar energy more effectively as multiple layers of a solar cell stack with different bandgaps capture and convert a broader range of incident spectra into electricity. It is crucial for tandem cells to have Transparent Conductive Oxide (TCO) with high transparency, high electrical conductivity, low reflection losses, and chemical stability so that their performance is boosted. In this numerical study, four different TCO layer materials—FTO (fluorine-doped tin oxide), ITO (indium tin oxide), IZO (indium zinc oxide), and MZO (magnesium-doped zinc oxide)—have been investigated with a tin-based perovskite-on-silicon structure (TCO/TiO2/MASnI3/Spiro-OMeTAD/c-SiOx/c-Si) for optimization and efficiency using SCAPS-1D simulation software. To reliably simulate tandem cells, optical filtering of bottom cells is achieved by calculating usable spectra from the top perovskite solar cell. The thickness of the TCO layer along with the selected material significantly affected the overall performance of the simulated solar cell. The best-case scenario among the four different materials was obtained from FTO as the TCO layer, which provided an open circuit voltage of 1.62 V, open circuit current of 20.52 mA cm−2, and efficiency of 25.34%. This study provides valuable insights into how TCO layer selection and optimization can lead to a more efficient, and thus more environmentally friendly, tandem solar cell configuration.