Controlled Humidity Study on the Formation of Higher Efficiency Formamidinium Lead Triiodide-Based Solar Cells

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• 作者：Sarah Wozny ; Mengjin Yang ; Alexandre M. Nardes ; Candy C. Mercado ; Suzanne Ferrere ; Matthew O. Reese ; Weilie Zhou ; Kai Zhu
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：July 14, 2015
• 年：2015
• 卷：27
• 期：13
• 页码：4814-4820
• 全文大小：425K
• ISSN：1520-5002

文摘

We report on the effect of humidity on the structural, optical, and electrical properties of formamidinium lead halide perovskite (FAPbI₃; prepared by a solvent engineering method) and the device characteristics of planar FAPbI₃ solar cells. The relative humidity strongly affects the perovskite film morphology, which changes from a uniform, fully covered FAPbI₃ film at low relative humidity (e.g., 鈭?%) to an inhomogeneous film consisting of many voids (or pinholes) at high humidity (30%鈥?0%). This morphological deterioration with increasing humidity is also accompanied by a reduction of the film crystallinity, decay of optical property, and shorter carrier lifetime. The device based on a planar FAPbI₃ film shows the best conversion efficiency of 16.6% (with the stabilized output efficiency of 16.4%) at a low humidity (鈭?%). Higher humidity leads to lower device performance, mainly due to the loss of open-circuit voltage and fill factor, which is consistent with the decrease in recombination resistance.