Giri Ashutosh, Chen Alexander Z, Mattoni Alessandro, Aryana Kiumars, Zhang Depei, Hu Xiao, Lee Seung-Hun, Choi Joshua J, Hopkins Patrick E
Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, United States.
Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904, United States.
Nano Lett. 2020 May 13;20(5):3331-3337. doi: 10.1021/acs.nanolett.0c00214. Epub 2020 Mar 31.
We report on the thermal conductivities of two-dimensional metal halide perovskite films measured by time domain thermoreflectance. Depending on the molecular substructure of ammonium cations and owing to the weaker interactions in the layered structures, the thermal conductivities of our two-dimensional hybrid perovskites range from 0.10 to 0.19 W m K, which is drastically lower than that of their three-dimensional counterparts. We use molecular dynamics simulations to show that the organic component induces a reduction of the stiffness and sound velocities along with giving rise to vibrational modes in the 5-15 THz range that are absent in the three-dimensional counterparts. By systematically studying eight different two-dimensional hybrid perovskites, we show that the thermal conductivities of our hybrid films do not depend on the thicknesses of the organic layers and instead are highly dependent on the relative orientation of the organic chains sandwiched between the inorganic constituents.
我们报告了通过时域热反射法测量的二维金属卤化物钙钛矿薄膜的热导率。由于铵阳离子的分子亚结构以及层状结构中较弱的相互作用，我们的二维杂化钙钛矿的热导率范围为0.10至0.19 W m⁻¹ K⁻¹，这大大低于其三维对应物的热导率。我们使用分子动力学模拟表明，有机成分会导致刚度和声速降低，同时在5 - 15太赫兹范围内产生三维对应物中不存在的振动模式。通过系统地研究八种不同的二维杂化钙钛矿，我们表明我们的杂化薄膜的热导率不取决于有机层的厚度，而是高度依赖于夹在无机成分之间的有机链的相对取向。
