Inverted hysteresis in MAPbI 3 perovskite solar cells induced by presetting bias voltage

Abstract The inverted hysteresis exhibits lower open-circuit voltage ( V OC ) of reverse scan than that of forward scan in the current–voltage characteristic of solar cells. Although it has been observed in different perovskite solar cells, the mechanism is not well understood. Here, we report that the inverted hysteresis can be induced by a presetting bias voltage in methylammonium lead triiodide perovskite solar cells. We found that applying a positive voltage bias equivalent to or slightly higher than the V OC between the two electrodes results in a significant reduction of V OC of the subsequent reverse scan. Moreover, the presetting voltage bias leads to a decrease and saturation feature of the dark current. In order to understand this phenomenon, we conducted numerical simulations on the current–voltage characteristic of the solar cells. The formation of interfacial barriers between the perovskite and the charge transport layers were considered in our simulations. The simulated results agree well with our experiments. Our work indicates that the interfacial barriers at the perovskite interfaces, originating from the presetting-bias-induced ion accumulation and film decomposition, exhibit a significant contribution to the inversed hysteresis.