Degradation by Exposure of Coevaporated CH3NH3PbI3 Thin Films

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• 作者：Youzhen Li ; Xuemei Xu ; Chenggong Wang ; Congcong Wang ; Fangyan Xie ; Junliang Yang ; Yongli Gao
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：October 22, 2015
• 年：2015
• 卷：119
• 期：42
• 页码：23996-24002
• 全文大小：508K
• ISSN：1932-7455

文摘

Degradation of coevaporated CH₃NH₃PbI₃ thin films were investigated with X-ray photoelectron spectroscopy and X-ray diffraction as the films were subjected to exposure of oxygen, low pressure atmospheric air, atmospheric air, or H₂O. The coevaporated thin films have consistent stoichiometry and crystallinity suitable for detailed surface analysis. The results indicate that CH₃NH₃PbI₃ is not sensitive to oxygen. Even after 10¹³ Langmuir (L, one L equals 10^鈥? Torr s) oxygen exposure, no O atoms could be found on the surface. The film is not sensitive to dry air as well. A reaction threshold of about 2 脳 10¹⁰ L is found for H₂O exposure, below which no CH₃NH₃PbI₃ degradation takes place, and the H₂O acts as an n-dopant. Above the threshold, the film begins to decompose, and the amount of N and I decrease quickly, leaving the surface with PbI₂, hydrocarbon complex, and O contamination.