题目：

Tracking the Formation of Methylammonium Lead Triiodide Perovskite

作者：

Lijia Liu,^a John A. McLeod,^a Rongbin Wang, Pengfei Shen, and Steffen Duhm

单位：

Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, 199 Ren’ai Road, Suzhou, Jiangsu 215123, China

摘要：

The formation mechanism of perovskite methylammonium lead triiodide (CH₃NH₃PbI₃) was studied with in situ X-ray photoelectron spectroscopy (XPS) on successive depositions of thermally evaporated methylammonium iodide (CH₃NH₃I) on a lead iodide (PbI₂) film. This deposition method mimics the “two-step” synthesis method commonly used in device fabrication. We find that several competing processes occur during the formation of perovskite CH₃NH₃PbI₃. Our most important finding is that during vapour deposition of CH₃NH₃I onto PbI₂, at least two carbon species are present in the resulting material, while only one nitrogen species is present. This suggests that CH₃NH₃I can dissociate during the transition to a perovskite phase, and some of the resulting molecules can be incorporated into the perovskite. The effect of partial CH₃NH₃ substitution with CH₃ was evaluated, and electronic structure calculations show that CH₃ defects would impact the photovoltaic performance in perovskite solar cells. The possibility that not all A sites in the APbI3 perovskite are occupied by CH₃NH₃ is therefore an important consideration when evaluating the performance of organometallic trihalide solar cells synthesized using typical approaches.

影响因子：

3.302

分区情况：

2区

链接：

http://scitation.aip.org/content/aip/journal/apl/107/6/10.1063/1.4928662