Kashyap Jatin, Yang Eui-Hyeok, Datta Dibakar
Department of Mechanical and Industrial Engineering, New Jersey Institute of Technology, Newark, NJ, 07103, USA.
Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
Sci Rep. 2020 Jul 9;10(1):11315. doi: 10.1038/s41598-020-68080-5.
The ubiquitous presence of wrinkles in two-dimensional materials alters their properties significantly. It is observed that during the growth process of graphene, water molecules, sourced from ambient humidity or transferred method used, can get diffused in between graphene and the substrate. The water diffusion causes/assists wrinkle formation in graphene, which influences its properties. The diffused water eventually dries, altering the geometrical parameters and properties of wrinkled graphene nanoribbons. Our study reveals that the initially distributed wrinkles tend to coalesce to form a localized wrinkle whose configuration depends on the initial wrinkle geometry and the quantity of the diffused water. The movement of the localized wrinkle is categorized into three modes-bending, buckling, and sliding. The sliding mode is characterized in terms of velocity as a function of diffused water quantity. Direct bandgap increases linearly with the initial angle except the highest angle considered (21°), which can be attributed to the electron tunneling effect observed in the orbital analysis. The system becomes stable with an increase in the initial angle of wrinkle as observed from the potential energy plots extracted from MD trajectories and confirmed with the DOS plot. The maximum stress generated is less than the plastic limit of the graphene.
二维材料中普遍存在的褶皱会显著改变其性能。据观察，在石墨烯的生长过程中，来自环境湿度或所用转移方法的水分子会扩散到石墨烯与基底之间。水的扩散导致/促使石墨烯中形成褶皱，这会影响其性能。扩散的水最终会干燥，改变褶皱石墨烯纳米带的几何参数和性能。我们的研究表明，最初分布的褶皱倾向于合并形成局部褶皱，其形态取决于初始褶皱几何形状和扩散水的量。局部褶皱的运动分为三种模式——弯曲、屈曲和滑动。滑动模式以速度作为扩散水量的函数来表征。除了所考虑的最大角度（21°）外，直接带隙随初始角度呈线性增加，这可归因于轨道分析中观察到的电子隧穿效应。从分子动力学轨迹提取的势能图观察到，并通过态密度图证实，随着褶皱初始角度的增加，系统变得稳定。产生的最大应力小于石墨烯的塑性极限。
