Pressure-induced transformation of CH₃NH₃PbI₃: the role of the noble-gas pressure transmitting media

A structural study of methyl­ammonium lead triiodide [CH₃NH₃PbI₃ (MAPbI₃)], at high pressures up to 20 GPa using noble gases Ne and Ar as pressure-transmitting media is reported. It is found that both noble gases are chemically active at high pressures. In particular, Ne stabilizes the high-pressure structure of Ne_xMAPbI₃ and prevents amorphization up to 20 GPa. In contrast, Ar acts as a stabilizer only up to 2.4 GPa and accelerates irreversible amorphization upon further compression.