Pyridine‐Carboxamide Bicyclic Molecules with Multi‐Site Anchoring for Flexible Perovskite Photovoltaics with Long Operational Lifetimes

The power conversion efficiency and operational stability of flexible perovskite solar cells (f-PSCs) are dependent on the grown quality of the perovskite films on buried interfaces. It is feasible to get such a high-merit perovskite via powerfully anchoring the undercoordinated ions on perovskite facets. Herein, we employ a unique pyridine-carboxamide molecule with rich anchoring sites to facilitate a preferential perovskite growth along the (100) plane. The nitrogen of the pyridine rings and the oxygen and amino of the carboxamide groups anchor the lead and iodine ions, leading to the formation of highly crystalline and large perovskite grains. The resultant f-PSCs yield a high power conversion efficiency of 25.17%. Moreover, importantly, after long-term ageing under 1-sun illumination for 2050 h, the f-PSCs retain 91.4% of their initial efficiency, illustrating one of the best operational stability among these f-PSCs. The work provides a bicyclic molecular passivation for making highly stable and efficient f-PSCs.