The Effects of the Organic–Inorganic Interactions on the Thermal Transport Properties of CH3NH3PbI3

详细信息    查看全文

• 作者：Tomoyuki Hata ; Giacomo Giorgi ; Koichi Yamashita
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：April 13, 2016
• 年：2016
• 卷：16
• 期：4
• 页码：2749-2753
• 全文大小：359K
• 年卷期：0
• ISSN：1530-6992

文摘

Methylammonium lead iodide perovskite (CH₃NH₃PbI₃), the most investigated hybrid organic–inorganic halide perovskite, is characterized by a quite low thermal conductivity. The rotational motion of methylammonium cations is considered responsible for phonon transport suppression; however, to date, the specific mechanism of the process has not been clarified. In this study, we elucidate the role of rotations in thermal properties based on molecular dynamics simulations. To do it, we developed an empirical potential for CH₃NH₃PbI₃ by fitting to ab initio calculations and evaluated its thermal conductivity by means of nonequilibrium molecular dynamics. Results are compared with model systems that include different embedded cations, and this comparison shows a dominant suppression effect provided by rotational motions. We also checked the temperature dependence of the vibrational density of states and specified the energy range in which anharmonic couplings occur. By means of phonon dispersion analysis, we were able to fully elucidate the suppression mechanism: the rotations are coupled with translational motions of cations, via which inorganic lattice vibrations are coupled and scatter each other.