The physics of photon induced degradation of perovskite solar cells

Lead-trihalide perovskite solar cells are an important photovoltaic technology. We investigate the effect of light induced degradation on perovskite solar cells. During exposure, the open-circuit voltage (V-oc) of the device increases, whereas the short-circuit current (I-sc) shows a decrease. The degradation can be completely recovered using thermal annealing in dark. We develop a model based on light induced generation of ions and migration of these ions inside the material to explain the changes in I-sc, V-oc, capacitance and dark current upon light exposure and post-exposure recovery. There was no change in defect density in the material upon exposure. (C) 2016 Author(s).