Temperature-Dependent Thermal Decomposition Pathway of Organic–Inorganic Halide Perovskite Materials

The thermal decomposition products and kinetics of two typical organic–inorganic halide perovskites, CH 3 NH 3 PbI 3 (MAPbI 3 ) and HC(NH 2 ) 2 PbI 3 (FAPbI 3 ), were investigated via simultaneous thermogravimetric analysis coupled with Fourier transform infrared spectroscopy. NH 3 and CH 3 I were verified as the major thermal decomposition gases of MAPbI 3 . Furthermore, for the first time, methane (CH 4 ) was observed as a thermal degradation product of MAPbI 3 at elevated temperatures. In contrast to conventional wisdom, (HCN) 3 (trimerized HCN) and NH 3 were demonstrated as the major gaseous decomposition products of FAPbI 3 at lower temperatures, while HCN and NH 3 became dominant at high temperatures (>360 °C). The hybrid experimental/theoretical results presented in this study will further our understanding of the perovskite decomposition mechanism and provide new insights into designing of long-term stable perovskite-based devices.