Fabrication of Efficient and Stable Perovskite Solar Cells in High-Humidity Environment through Trace-Doping of Large-Sized Cations

Graphical Perovskite solar cells : Perovskite with trace doping of 0.01 % tert -butylammonium iodide preserves its excellent optoelectronic properties, leading to a high power conversion efficiency (PCE) of 19.3 % and a high fill factor of 0.8. High-efficiency perovskite solar cells are fabricated under a high-humidity environment of 50 % relative humidity (RH); these cells realize good humidity and heat stabilities. Solution-processed organic–inorganic lead halide perovskites have shown photovoltaic performance above 23 %, attracting great attention. However, the champion devices require fabrication in a controlled inert/dry atmosphere. The development of highly efficient and stable perovskite solar cells under high-humidity atmosphere conditions for future commercialization is still challenging, especially for CH 3 NH 3 PbI 3 (MAPbI 3 ), which is vulnerable to moisture. In this study, a large-sized tert -butylammonium [C(CH 3 ) 3 NH 3 + ] organic cation was incorporated into the MAPbI 3 crystalline structure, which could form a more stable 3 D crystalline structure and alleviate the decomposition caused by the humidity. It delivered a power conversion efficiency of 19.3 % upon preparation under a humid environment condition of 50 % relative humidity as well as improved humidity and thermal stability. Our work provides a facile strategy for improving perovskite performance and stability by introducing a new chemical additive for the future application of perovskite solar cells.