Interfacial Chemical Bridge Constructed by Zwitterionic Sulfamic Acid for Efficient and Stable Perovskite Solar Cells
Haoran Xia, Xing Li, Jiyu Zhou, Boxin Wang, Yanmeng Chu, Yanxun Li, Guangbao Wu, Dongyang Zhang, Baoda Xue, Xuning Zhang, Yue Hu, Huiqiong Zhou, Yuan Zhang
Abstract
A simple-structure zwitterion of sulfamic acid (+H3N–SO3–, SA) is introduced to construct an effective chemical bridge between SnO2 and a perovskite layer through a coordination bond via the -SO3– anion for remedying the oxygen vacancies of SnO2 and meanwhile to passivate charged defects of the perovskite through electrostatic interaction via the -NH3+ cation. The introduced SA results in high-quality perovskite films with large grain size, due to the better wettability for perovskite solution. Consequently, the SA-modified solar cell generates an enhanced efficiency from 18.2% to 20.4% with negligible hysteresis. Remarkably, the unsealed device with SA modification also exhibits considerably improved stability.