An Evaporative Surface Modulation for Efficient Inverted Perovskite Photovoltaics

Non-radiative recombination losses caused by defects and poor resistance to ambient moisture significantly undermine the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs), presenting major challenges to their industrial application. Effective passivation of these defects and enhanced moisture resistance are thus critical for optimizing device performance and reliability. Here, the introduction of a perfluorinated surface modulator, perfluorotripropylamine hydroiodide (PFTPAI), is reported for the first time into inverted perovskite solar cells. Owing to its relatively low boiling point, PFTPAI predominantly evaporates upon annealing, leaving behind a modulated perovskite surface. During this process, it interacts with the perovskite, effectively modifying and reorganizing the surface morphology while simultaneously achieving defect passivation, resulting in enhanced film quality. The champion PFTPAI-modified PSCs achieve an outstanding PCE of 26.27% (26.24%, certificated), an open-circuit voltage of 1.175 V, and a fill factor of 85.26%. Furthermore, these devices demonstrate exceptional operational and stability, retaining over 90% of their initial PCE after 1000 h of continuous operation and effectively improved the moisture resistivity, highlighting the evaporative surface modulator, PFTPAI, as a promising modulator for advancing the performance and stability of PSCs toward commercial viability.