Lattice mode symmetry analysis of the orthorhombic phase of methylammonium lead iodide using polarized Raman
Lattice mode symmetry analysis of the orthorhombic phase of methylammonium lead iodide using polarized Raman
复制标题
DOI：
10.1103/physrevmaterials.4.051601
复制
发表时间：
2020-05
影响因子：
3.4
通讯作者：
Rituraj Sharma;M. Menahem;Zhenbang Dai;Lingyuan Gao;Thomas M. Brenner;L. Yadgarov;Jiahao Zhang;Y. Rakita;R. Korobko;I. Pinkas;A. Rappe;O. Yaffe
中科院分区：
文献类型：
--
作者：
Rituraj Sharma;M. Menahem;Zhenbang Dai;Lingyuan Gao;Thomas M. Brenner;L. Yadgarov;Jiahao Zhang;Y. Rakita;R. Korobko;I. Pinkas;A. Rappe;O. Yaffe
在过去的十年里，有机-无机混合卤化物钙钛矿作为一种新型的半导体材料出现在光伏和其他光电子领域。与标准的四面体键合半导体(如Si和GaAs)不同，卤化物钙钛矿中的离子热涨落(即结构动力学)与电子动力学强烈耦合。因此，获得关于晶体内原子运动性质的准确和详细的知识是至关重要的。这已被证明是具有挑战性的，因为低热稳定性和卤化物钙钛矿复杂的、依赖于温度的结构相序。在这里，我们克服了这些挑战，并详细分析了甲基铵-碘化铅低温正交相中的模式对称性。利用1.16 eV的线偏振光和圆偏振光，结合密度泛函微扰理论(DFPT)进行了拉曼光谱测量。通过对拉曼偏振-取向关系的迭代分析和DFPT模式分析，确定了晶体取向。随后，考虑了圆偏振光激发下的双折射效应，给出了10K下所有观测到的拉曼有效模的对称性。
In the last decade, hybrid organic-inorganic halide perovskites have emerged as a new type of semiconductor for photovoltaics and other optoelectronic applications. Unlike standard, tetrahedrally bonded semiconductors (e.g. Si and GaAs), the ionic thermal fluctuations in the halide perovskites (i.e. structural dynamics) are strongly coupled to the electronic dynamics. Therefore, it is crucial to obtain accurate and detailed knowledge about the nature of atomic motions within the crystal. This has proved to be challenging due to low thermal stability and the complex, temperature dependent structural phase sequence of the halide perovskites. Here, these challenges are overcome and a detailed analysis of the mode symmetries is provided in the low-temperature orthorhombic phase of methylammonium-lead iodide. Raman measurements using linearly- and circularly- polarized light at 1.16 eV excitation are combined with density functional perturbation theory (DFPT). By performing an iterative analysis of Raman polarization-orientation dependence and DFPT mode analysis, the crystal orientation is determined. Subsequently, accounting for birefringence effects detected using circularly polarized light excitation, the symmetries of all the observed Raman-active modes at 10 K are assigned.