Department of Chemical and Biological Engineering, The University of Alabama , Box 870203, Tuscaloosa, Alabama 35487, United States.
Langmuir. 2016 Oct 4;32(39):9982-9992. doi: 10.1021/acs.langmuir.6b02663. Epub 2016 Sep 22.
Bismuth telluride (BiTe) is a well-known thermoelectric material with potential applications in several different emerging technologies. The bulk structure is composed of stacks of quintuple sheets (with weak interactions between neighboring sheets), and the performance of the material can be significantly enhanced if exfoliated into two-dimensional nanosheets. In this study, eight different imidazolium-based ionic liquids are evaluated as solvents for the exfoliation and dispersion of BiTe at temperatures ranging from 350 to 550 K. Three distinct exfoliation mechanisms are evaluated (pulling, shearing, and peeling) using steered molecular dynamics simulations, and we predict that the peeling mechanism is thermodynamically the most favorable route. Furthermore, the [TfN]-based ionic liquids are particularly effective at enhancing the exfoliation, and this performance can be correlated to the unique molecular-level solvation structures developed at the BiTe surfaces. This information helps provide insight into the molecular origins of exfoliation and solvation involving BiTe (and possibly other layered chalcogenide materials) and ionic liquid solvents.
碲化铋（BiTe）是一种众所周知的热电材料，具有在几种新兴技术中应用的潜力。其体相结构由五重层堆叠组成（相邻层之间的相互作用较弱），如果剥离成二维纳米片，材料的性能可以显著提高。在这项研究中，评估了八种不同的咪唑基离子液体作为在 350 到 550 K 温度范围内剥离和分散 BiTe 的溶剂。使用导向分子动力学模拟评估了三种不同的剥离机制（拉伸、剪切和剥离），我们预测剥离机制在热力学上是最有利的途径。此外，基于[TfN]的离子液体在增强剥离方面特别有效，这种性能可以与在 BiTe 表面形成的独特的分子级溶剂化结构相关联。这些信息有助于深入了解涉及 BiTe（可能还有其他层状硫属化物材料）和离子液体溶剂的剥离和溶剂化的分子起源。
