Energy Landscape of Molecular Motion in Cubic Methylammonium Lead Iodide from First-Principles

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• 作者：Jonathon S. Bechtel ; Ram Seshadri ; Anton Van der Ven
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：June 16, 2016
• 年：2016
• 卷：120
• 期：23
• 页码：12403-12410
• 全文大小：569K
• 年卷期：0
• ISSN：1932-7455

文摘

Molecular A-cation dynamics are known to play a role in the electronic properties and structure of hybrid organic–inorganic ABX₃ perovskites such as CH₃NH₃PbI₃. We calculate the full energy landscape for rigid-body rotations and translations of the methylammonium cation in the cubic phase of CH₃NH₃PbI₃. Energy barriers are calculated for combinations of molecular reorientation, on-axis rotation, and molecular translation within the unit cell. Allowing molecular translations significantly stabilizes orientations along [100] which we attribute to strong N–H···I interactions between CH₃NH₃⁺ and the inorganic Pb–I host lattice.