Multifunctional Regulation of Highly Orientated Tin–Lead Alloyed Perovskite Solar Cells
Xiafei Jiang, Chongwen Li, Xianzhao Wang, Cheng Peng, Haokun Jiang, Hongkai Bu, Mingzhe Zhu, Hang Yin, Benlin He, Haiyan Li, Shuping Pang, Zhongmin Zhou
Abstract
Tin–lead (Sn–Pb) alloyed perovskites are promising candidates for next-generation photovoltaics due to their appropriate bandgaps for multijunction tandem solar cells, which can potentially overcome the Shockley-Queisser limit. However, their power conversion efficiency (PCE) and stability are still impeded by the poor absorber quality and defects caused by the oxidation of Sn 2+ . Here, we introduced trimethylsulfoxonium iodide (TMSI) as an additive along with SnF 2 to fabricate Sn–Pb perovskite films with enlarged grains and improved film quality. TMSI restrained the oxidation of Sn 2+ through molecular interactions, reducing the formation of detrimental Sn vacancies. As a result, a highly oriented Sn–Pb alloyed perovskite with a lower defect density was obtained, along with suppressed ion migration. The TMSI-treated Sn–Pb-based devices exhibited a champion PCE of 22.6% and outstanding stability, retaining 83% of their original efficiency after 6000 h of storage under a N 2 atmosphere and maintaining 88% of their initial value after 1200 h of continuous one-sun illumination.