石墨烯及其拼接结构的“水波效应”

发布时间：2018-03-07 08:53

本文选题：石墨烯　切入点：线型碳　出处：《山东大学》2015年硕士论文　论文类型：学位论文

【摘要】：在过去的几十年中,低维碳材料在各方面的研究得到了飞速的发展,尤其是二维碳材料——石墨烯的成功制备,引发了关于低维材料的前所未有的研究热潮。石墨烯,作为一种新型的碳纳米材料,由于在力学、电学、光学以及热学等方面表现出的优异性能,具有非常广阔的应用前景。石墨烯表面的涟漪,作为一种固有属性,对其机械性能、电子特性以及磁性质都会产生较大的影响。然而,由于这些固有涟漪是自发形成、无序分布的,所以在很大程度上限制了其应用范围。如果能够对石墨烯中波纹的结构和分布进行人为地控制和设计,就可以更好地扩大其应用范围。因此,对石墨烯中可控波纹的产生方法以及规律特征展开探究将具有重要的理论意义和潜在的实用价值。本论文主要采用经典分子动力学模拟的方法分别对单层完美石墨烯、缺陷石墨烯、由一维的线型碳或者石墨烯纳米带连接两片石墨烯所组成的拼接结构的“水波效应”进行了研究,从形变和能量的角度出发,揭示了石墨烯及其缺陷、线型碳以及石墨烯纳米带的一些性质,丰富了碳纳米材料中波纹的研究成果,对于其潜在的应用具有理论参考意义。本论文主要的研究成果如下：(1)石墨烯受到C60撞击之后会产生“水波效应”,动态波纹的轮廓经历了从最初的“六边形”变为“多边形”最后趋于“圆形”的过程。在分析波纹的位移时,发现波纹在石墨烯中的传播过程呈现出阻尼特征,峰值随着离开撞击点距离的增加呈指数衰减。在波纹传播的同时也伴随着能量的传播,集中在撞击点处的应变能以动态波纹的形式呈放射状向周围分散,避免了局部能量集中,体现了石墨烯良好的能量缓冲性能,有望在表面保护方面发挥作用。(2)SW缺陷以及空位缺陷的引入会对波纹在石墨烯中的传播过程产生影响,不仅会使波纹的位移分布轮廓变得不规则,而且分析结果表明,SW缺陷和空位缺陷都善于从波纹中吸收能量,并将其贮存在自身内部,而不能有效地将吸收的能量传递出去,石墨烯缺陷的这种特性也预示了其在储能领域具有应用前景。另外,还探究了温度对于“水波效应”的影响作用。温度的升高,不仅使波纹的振幅明显增加,波纹的传播速度加快,而且还会增强缺陷对于波纹传播的影响效果。(3)在由一维的线型碳或者石墨烯纳米带连接两片石墨烯所组成的拼接结构中,小片的石墨烯受到C60撞击后,会产生“水波效应”,并且波纹能够通过中间连接的线型碳或者石墨烯纳米带传播到大片石墨烯,但是波的强度明显减小。大片石墨烯的位移以及能量分布结果表明,石墨烯纳米带可以比线型碳更快、更有效地将波纹从小片石墨烯传递到大片石墨烯。所以,从传输机械波的角度来看,无论是在传递速度还是传递效率方面,石墨烯纳米带都比线型碳具有更好的机械传输性能。本论文在石墨烯及其缺陷的性质方面取得了新的研究成果,为其在表面保护以及储能等领域的潜在应用提供了理论支持。对石墨烯纳米带和线型碳机械传输性能的对比研究,丰富了碳纳米材料在波纹传播方面的研究结果,对于其潜在的应用具有理论参考价值。
[Abstract]:In the past few decades, the study of low dimensional carbon materials in all aspects of the rapid development, especially the successful preparation of two-dimensional carbon material, graphene, triggered a hitherto unknown low dimensional materials researchers. Graphene, as a new type of carbon nano materials, in the mechanical, electrical excellent performance, optical and thermal aspects, has a very broad application prospects. The graphene surface ripples, as a kind of inherent attribute, on the mechanical properties, electrical properties and magnetic properties will have a greater impact. However, due to the inherent ripple is spontaneously formed, disordered distribution, and so on largely limits its application scope. If the structure and distribution of corrugated graphene in the artificial control and design, will be better able to expand its scope of application. Therefore, the controllable graphene ripples The method and characteristic of inquiry will have important theoretical significance and potential practical value. This thesis mainly adopts the methods of classical molecular dynamics simulation of single perfect graphene, graphene defects, from one-dimensional linear carbon or graphene nanoribbons connecting two sheets of graphene consisting of the mosaic structure of the "wave effect of deformation and starting from the angle of energy and reveals the defects of graphene and its linear carbon graphite, and some properties of graphene nanoribbons, enriches the research results of corrugated carbon nano materials, has theoretical significance for its potential application. The main achievements of the thesis are as follows: (1) after the graphene by C60 impact will produce" ripple effect ", the dynamic wave contour experienced from the initial" hexagon "into" polygon "finally become" round " In the analysis process. The displacement of corrugated, corrugated graphene in the propagation process found in showing the damping characteristics, with increased peak left impact point distance decay exponentially. The corrugated spread is also accompanied by the spread of the energy, the strain is concentrated in the impinging point to the dynamic wave form radially to spread everywhere, to avoid the local concentration of energy reflects the energy buffering properties of graphene good, is expected to play a role in surface protection. (2) SW defects and vacancies introduced will influence on the ripple in graphene the propagation process of production, not only makes the displacement distribution contour of the ripple becomes irregular, and the analysis results show that the SW defects and vacancy defects are good at absorbing energy from the bellows, and it has its own internal storage, and can not effectively transfer the absorbed energy out, the characteristics of graphene defects Also indicates its application prospect in energy storage field. In addition, it also explores the temperature influence on the "ripple effect". The increase of temperature, not only the ripple amplitude is obviously increased, wave propagation speed, but also enhance the effect of defects on the ripples spread. (3) in a one-dimensional linear carbon or graphene nanoribbons connect two graphene consisting of mosaic structure, small pieces of graphene by C60 after the impact, will have a "ripple effect", and through the middle connecting line of corrugated carbon or graphene nanoribbons spread to large graphene, but the intensity of the wave decreased. Large graphene the displacement and energy distribution. The results show that the graphene nanoribbons can be faster than linear carbon, more effectively will transfer from small corrugated graphene to large graphene. So, from the point of view of mechanical wave transmission, Whether or transfer efficiency in the transmission speed, mechanical transmission performance of graphene nanoribbons are better than linear carbon. This thesis has made new achievements in the properties of graphene and its defects, for the surface protection and storage can provide theoretical support for potential application in the fields of comparative study on graphite. Graphene nanoribbons and linear carbon mechanical transmission performance, enrich the research results in the spread of corrugated carbon nano material, has a theoretical reference value for its potential applications.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ127.11

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