| Abstract Scope |
Despite high efficiency, the poor stability poses a critical challenge for hybrid perovskite solar cells, which is largely caused by the ingression of moisture and an enhanced ion migration through grain boundaries (GBs). In this talk, I will overview the additive approach for passivating GBs and subsequently improving the stability of hybrid perovskite solar cells. For example, a new linear polymer additive, polycaprolactone (PCL), could functionalize GBs in methylammonium lead triiodide (MAPI) perovskites via direct backbone attachment, leading to the champion power conversion efficiency of 20.1% with vastly improved structural and chemical stabilities under thermal and moisture exposure conditions. Complementary physicochemical characterizations including transmission electron microscopy, infrared, and secondary ion mass spectroscopies confirmed a significantly suppressed ion migration by PCL [Zhou <i>et al.</i>, <i>Chem. Mater.</i> <b>32</b>, 5104 (2020)]. I will also briefly discuss other additives and processing techniques effective for enhancing the performance and stability of hybrid perovskite solar cells. |