Evolution characteristics of perovskite solar cells in air and vacuum environments

Solid state hybrid organometal halide perovskite solar cells have become the research hotspots recently. We prepared perovskite solar cells by the simple two-step method in the ambient condition. The solar cell samples were kept in air and vacuum environments, respectively. Jsc shows good stability in vacuum for up to 27 days, while it drops a lot in air. There is a remarkable promotion of FF for the air-stored samples compared that of the vacuum-stored samples. Changes in Voc of vacuum-stored and air-stored samples exhibited a similar behavior, both showing a slight increase. We believe the moisture in air makes perovskite decompose which leads to the decrease of Jsc, and the HTM material can be oxidized in air and its conductivity will be improved, which is beneficial to the FF.