Optimization of Bulk Defects in Sn/Pb Mixed Perovskite Solar Cells Through Synergistic Effect of Potassium Thiocyanate

摘要

The organic-inorganic Sn-Pb mixed perovskite has achieved great progressduring the last 10 years and is considered as one of the most promising lowbandgapphotovoltaic materials. It has lower toxicity, outstanding optoelectricalproperties, and achieved remarkable performance. However, there are still plentyof challenges in controlling the morphology, crystallinity, and defects of theSn-Pb mixed perovskite film because of the inferior chemical stability of Sncompared with Pb. Herein, it is found that the synergistic effect of potassiumthiocyanate (KSCN) in the Sn-Pb mixed perovskites can enlarge the grain size,enhance the crystallization, improve the film morphology, and obtain high-qualityperovskite films which effectively eliminate the bulk defects and smooth carriertransportation of Sn-Pb mixed perovskite solar cells. Through optimizing theconcentration of KSCN, a high-performance MA_(0.5)FA_(0.5)Pb_(0.5)Sn_(0.5)I_3 solar cellwith an efficiency of 15.14% and improved stability is obtained. This work lays akey foundation for the fabrication of efficient and stable Sn-based or Sn-Pb mixedperovskite solar devices.