Towards the Working Mechanisms of Tin Oxide as Buffer Layer in Perovskite/Silicon Tandem Solar Cells

Tin oxide (SnOX), the commonly used buffer layer to protect both the electron transporting layer and perovskite layer from sputtering-induced damage during transparent conductive oxide deposition in the top cell of the perovskite-related tandem solar cells, is considered essential for achieving high efficiency. In our work, for the first time, we systematically investigated the impact of SnOX on single-junction perovskite solar cells as a platform to understand the working mechanism of SnOX in perovskite top cell. The correlation between the SnOX process parameters and the photovoltaic parameters were discussed independently using steady state photoluminescence, external quantum efficiency and numerical simulations. It is observed that the efficiency increased with thicker SnOX and the results suggest that thicker SnOX not only decreased the series resistance of perovskite solar cells but also has a potential of suppressing non-radiative recombination.