An image of a perovskite silicon tandem solar cell made by the researchers. A perovskite silicon tandem solar cell features a top cell made from perovskite and a bottom cell of silicon. The silicon in perovskite silicon tandem solar cell is textured to increase its surface area and efficiency. “For today’s silicon solar cells, surface passivation was the key for high efficiencies in industrial production,” says Glunz. “It is encouraging that the photovoltaic industry will benefit from these positive effects for perovskite silicon tandem solar cells as well.”