Improving Reverse Bias Stability and Ion Migration in Perovskite Solar Cells

Ion migration and reverse bias stability are recognized as potential barriers to commercial photovoltaic applications of halide perovskite semiconductors. In this talk we will discuss our work on scalable interface passivation layers, quantification of their reductions in interfacial defect densities, and will show how they are able to suppress halide vacancy migration both under illumination and under voltage bias. Next, we study how device architecture engineering can have a significant impact on the reverse bias behavior of perovskite solar cells. Surprisingly, while past research has emphasized the role hole tunneling from across the electron transport layer on reverse bias instabilities, we show that by using a thicker conjugated polymer hole transport layer, and a more electrochemically stable back electrode, we can realize average breakdown voltages exceeding -15 V, comparable to those of silicon cells, demonstrating cells that can survive reverse bias under partial shading for hours at a time.