Perovskite solar cells could be a low-cost alternative to those based on silicon. The efficiency of cells made from hybrid organic–inorganic halide perovskites has risen considerably over the past years, from roughly 3 % to over 20 %. However, their stability is still insufficient, particularly in the presence of moisture or heat.
Licheng Tan, Yiwang Chen, Nanchang University, China, and colleagues have used a fluorinated perylenediimide (F‐PDI) to protect a perovskite film against humidity and improve its thermal stability. The team used the hydrophobic and semiconductive compound N,N‘‐bis‐(1,1,1,2,2,3,3,4,4‐nonafluorododecan‐6‐yl)‐perylenediimide (pictured in blue) to coat methylammonium lead iodide perovskite, MAPbI3 (pictured in orange). This hybrid material was then used in solar cells.
The F-PDI passivates defects in the perovskite, which protects the cell against degradation by humidity. Strong hydrogen bonding involving the fluorine substituents of F-PDI can immobilize methylamine ions and thus, enhance, the thermal stability of the device. F-PDI also promotes charge transport across grain boundaries due to the chelation between its carbonyl and the perovskite’s lead, which improves performance. Over 80 % of the solar cells’ initial efficiency is retained after exposure to air with a relative humidity of 50 % for 30 days.
- High-Performance Perovskite Solar Cells with Excellent Humidity and Thermo-Stability via Fluorinated Perylenediimide,
Jia Yang, Cong Liu, Chunsheng Cai, Xiaotian Hu, Zengqi Huang, Xiaopeng Duan, Xiangchuan Meng, Zhongyi Yuan, Licheng Tan, Yiwang Chen,
Adv. Energy Mater. 2019, 9, 1900198.