Improving Photovoltaic Performance and Stability of Perovskite Solar Cells via Molecular Bridge Strategy

Although perovskite solar cells (PSCs) are regarded as one of the most promising photovoltaic technologies, the interfacial defects and energy barrier are the main bottlenecks for further improving their photovoltaic performance and stability. Herein, an effective, facile "molecular bridge" strategy to improve the photovoltaic performance and stability of PSCs simultaneously is reported. This strategy is realized by introducing a self-assembly molecule, namely, 5-fluoro-pyridine carboxylic acid (5-FPA), to modify the SnO2/perovskite buried interface. The functional groups (F and C(sic)O) of 5-FPA form strong chemical interactions with perovskite and SnO2 layers, which improve interfacial carrier extraction and perovskite film quality with better crystallization and less strain. As a result, photovoltaic performance is substantially improved with power conversion efficiencies exceeding 23%, accompanied by enhanced stability under thermal and ambient conditions. This study opens a new avenue to improve the performance and stability of perovskite photovoltaics through the "molecular bridge" strategy.