2,2′‐Bipyridyl‐4,4′‐Dicarboxylic Acid Modified Buried Interface of High‐Performance Perovskite Solar Cells
Mingming Zhao, Wei‐Min Gu, Ke‐Jian Jiang, Xinning Jiao, Kun Gong, Fengzhu Li, Xueqin Zhou, Yanlin Song
Abstract
Abstract The regulation of interfaces remains a critical and challenging aspect in the pursuit of highly efficient and stable perovskite solar cells (PSCs). Here, 2,2′‐bipyridyl‐4,4′‐dicarboxylic acid ( HBPDC ) is incorporated as an interfacial layer between SnO 2 and perovskite layers in PSCs. The two carboxylic acid moieties on HBPDC bind to SnO 2 through esterification, while its nitrogen atoms, possessing lone electron pairs, interact with uncoordinated lead (Pb 2+ ) atoms through Lewis acid‐base interactions. This dual functionality enables simultaneous passivation of surface defects on both the SnO 2 and buried perovskite layers. In addition, the electron‐deficient nature of HBPDC enhances interfacial energy band alignment and facilitates electron transfer from the perovskite to SnO 2 . Furthermore, the incorporation of HBPDC strengthens the interfacial adhesion, improving mechanical reliability. As a result, the PSCs exhibited an impressive power conversion efficiency (PCE) of 25.41 % under standard AM 1.5G conditions, along with remarkable environmental stability.