含拓扑缺陷的石墨烯表面起伏的分子动力学研究

Graphene, the first example of strict 2D crystal so far, is one of the most promising materials in nanotechnology because of its outstanding electronic, optical and mechanical properties. But structural defects, such as topological defects, which may appear during growth or processing of graphene, deteriorate the dynamical properties and structural stability of graphene-based devices. As the two most typical examples, Stone-Wales (SW) and Grain Boundary (GB) defects are attracting more and more attention. With all the previous works established, the project aims at studying the mechanical properties and structural stability of grahenes with SW and GB defects. We will mainly investigate the dependence of graphene ripples on the following aspects, respectively. One is the concentration of the SW defects, and the other is the arrangements of the GB defects. At the same time, we also pay the attention to the hybrid zigzag-GB-armchair graphene, in which the incommensurability of the graphene ribbons in the zigzag and armchair directions can induce different stress. Finally, by comparing the related results at the two different kinds of defects with the case of pristine graphene, we will obtain the general law for structural stability of graphene with defects. And this work will supply the using for graphene-based nanomaterials and functional devices with the theoretical support.

石墨烯作为一种迄今为止最严格的二维新物质，因其优越的电子、光学和机械等方面的性能，已成为最具前途的纳米材料之一。而在制备石墨烯的过程中，常会出现各种类型的缺陷，较典型的是以Stone-Wales（SW）和Grain Boundary（GB）为代表的拓扑缺陷，它们必然会影响石墨烯的动力学特性和结构稳定性。本项目拟在前期研究成果的基础上，以含有SW和GB缺陷的单层石墨烯及zigzag-GB-armchair复合型石墨烯的力学性能和结构稳定性为主要研究目标，重点考查不同浓度的SW缺陷和不同排布方式的GB缺陷对石墨烯表面起伏的影响，同时关注zigzag-GB-armchair复合型石墨烯中因zigzag和armchair部分的结构不对称性带来的应力差异。通过将含有这两种缺陷的石墨烯表面起伏与完整石墨烯的情况作对比，总结出石墨烯在含有拓扑缺陷时的结构稳定性规律，为石墨烯纳米材料的应用提供理论支持。

本项目的主要研究对象是石墨烯，它作为一种迄今为止最严格的二维新物质，因其优越的电子、光学和机械等方面的性能，已成为最具前途的纳米材料之一。而在制备石墨烯的过程中，常会出现各种类型的缺陷，较典型的是以Stone-Wales (SW)和Grain Boundary (GB)为代表的拓扑缺陷，它们必然会影响石墨烯的动力学特性和结构稳定性。本项目以含有SW和GB缺陷的单层石墨烯及zigzag-GB-armchair 复合型石墨烯的力学性能和结构稳定性为主要研究目标，重点考查不同浓度的SW缺陷和不同排布方式的GB缺陷对石墨烯表面起伏的影响，同时关注zigzag-GB-armchair复合型石墨烯中因zigzag和armchair部分的结构不对称性带来的应力差异。通过将含有这两种缺陷的石墨烯表面起伏与完整石墨烯的情况作对比，总结出石墨烯在含有拓扑缺陷时的结构稳定性规律，为石墨烯纳米材料的应用提供理论支持。除了研究含有上述拓扑缺陷的石墨烯之外，我们也考查了不同堆积方式的多层石墨烯，诸如ABA、ABC堆积的三层石墨烯和ABAB、ABCA堆积的四层石墨烯，关注温度和堆积方式对这些材料的表面起伏的影响，并对多层石墨烯表面起伏的不同特性作出合理的解释。