Regulation of Buried Interface through the Rapid Removal of PbI<sub>2</sub>·DMSO Complex for Enhancing Light Stability of Perovskite Solar Cells
Xing Zhao, Yujie Qiu, Min Wang, Danxia Wu, Xiaopeng Yue, Huilin Yan, Bingbing Fan, Shuxian Du, Yuqing Yang, Yingying Yang, Danni Li, Peng Cui, Hao Huang, Yingfeng Li, Nam‐Gyu Park, Meicheng Li
Abstract
The presence of the detrimental PbI 2 residue at the buried interface negatively affects the photovoltaic performance of perovskite solar cells (PSCs). However, the underlying mechanism involved in the formation and elimination of residual PbI 2 has been rarely investigated, despite its critical significance for high-efficiency and stable PSCs. Here, we investigated the formation and elimination mechanism of residual PbI 2 at the buried interface influenced by citric acid (CA) and found that CA can quickly remove the PbI 2 ·DMSO complex through a competitive adsorption mechanism by forming highly crystallized PbI 2 . This promotes the subsequent intercalation of amine cations into the PbI 2 framework by forming a stable perovskite. Consequently, the best-performing target PSC achieves an efficiency of 25.19% (a certified efficiency of 24.64%) and 23% from a 1 cm 2 PSC. Additionally, the target PSC also demonstrates improved light stability after 200 h of UV light soaking by maintaining 94.21% of its initial efficiency compared with only 70.76% for the control PSC.