Room Temperature as a Goldilocks Environment for CH3NH3PbI3 Perovskite Solar Cells: The Importance of Temperature on Device Performance

Terrestrial applications of solar cells during day–night cycling as well as operation in winter and summer involve substantial temperature variations, which influence the photophysics as well as the charge separation and transport properties in the various materials employed in a device. In this study, the optical absorption of methylammonium lead iodide (MAPbI3) and the device performance of MAPbI3 solar cells have been investigated in an extended temperature range between −190 and 80 °C. The optical properties were found to change by only a small amount in that temperature range. The device performance did, however, show more dramatic changes and decreased in a reversible manner for temperatures both higher and lower than room temperature. For temperatures up to 80 °C and down to −80 °C, the drop in performance was up to 25% compared to the room temperature value. Given thermal stability and reversible device performance, this is probably not a showstopper for terrestrial applications of perovskite sola...