January 2019: Professor Jan Seidel & Dohyung Kim "Light- and bias-induced structural variations in metal halide perovskites"
"Schematic illustration of photo-assisted scanning probe microscopy"
Organic-inorganic metal halide perovskites have gained considerable attention for next-generation photovoltaic cells due to rapid improvement in power conversion efficiencies. Our work makes use of complementary nanoscale scanning probe microscopy imaging techniques, specifically PFM, KPFM, and AFM to identify structural variations of metal halide perovskites under varying light illumination and bias conditions. In addition, we performed in-situ XRD measurements to reveal an increase of structural disorder under such applied external stimuli. We show evidence and propose a mechanism describing how the observed structural changes can influence charge carrier transport and I-V hysteresis in actual solar cell devices. Our results thus provide further insight into nanoscale structural variations in operating solar cells for improving the design of halide perovskite photovoltaic devices.
Read the full paper, as published in Nature Communications (10, 444 (2019)).