基于分子动力学的石墨炔纳米带空位缺陷的导热特性

发布时间：2018-02-15 00:51

本文关键词： 石墨炔纳米带分子动力学空位缺陷热导率　出处：《物理学报》2017年13期 　论文类型：期刊论文

【摘要】：空位缺陷石墨炔比完整石墨炔更贴近实际材料,而空位缺陷的多样性可导致更丰富的导热特性,因此模拟各种空位缺陷对热导率的影响显得尤为重要.采用非平衡分子动力学方法,通过在纳米带长度方向上施加周期性边界条件,基于AIREBO(adaptive intermolecular reactive empirical bond order)势函数描述碳-碳原子间的相互作用,模拟了300 K时单层石墨炔纳米带乙炔链上单空位缺陷和双空位缺陷以及苯环上单空位缺陷对其热导率的影响,利用Fourier定律计算热导率.模拟结果表明,对于几十纳米尺度范围内的石墨炔纳米带热导率,1)由于声子的散射集中和声子倒逆过程增强,与完美无缺陷的石墨炔纳米带相比,空位缺陷会导致石墨炔纳米带热导率的下降;2)由于声子态密度匹配程度高低的不同,相比于乙炔链上的空位缺陷,苯环的空位缺陷对石墨炔纳米带热导率影响更大,乙炔链上空位缺陷数量对石墨炔纳米带热导率的影响明显;3)由于尺寸效应问题,随着长度增加,石墨炔纳米带热导率会相应增大.本文的研究可为在一定尺度下进行石墨炔纳米带热导率的调控问题提供参考.
[Abstract]:The vacancy defect graphite acetylene is closer to the actual material than the complete graphite acetylene, and the diversity of the vacancy defect can lead to more abundant thermal conductivity. Therefore, it is very important to simulate the effect of various vacancy defects on thermal conductivity. By applying periodic boundary conditions in the length direction of nanobelts, the method of nonequilibrium molecular dynamics is used. Based on the AIREBO(adaptive intermolecular reactive empirical bond order function to describe the interaction between carbon and carbon atoms, the effects of single vacancy defect and double vacancy defect on the thermal conductivity of acetylene chain in single layer graphite nanoribbons at 300K were simulated. Fourier's law is used to calculate the thermal conductivity. The simulation results show that the thermal conductivity of graphene nanobelts in the range of dozens of nanometers is enhanced by phonon scattering concentration and phonon inversion process, which is compared with that of perfect graphene nanoribbons. Vacancy defects will lead to the decrease of thermal conductivity of graphite nanobelts. (2) compared with the vacancy defects in acetylene chain, the vacancy defects of benzene ring have more influence on the thermal conductivity of graphite nanobelts due to the difference of the matching degree of phonon density. The effect of the number of vacancy defects in acetylene chain on the thermal conductivity of graphite nanobelts is obvious. The thermal conductivity of graphite nanobelts will increase accordingly. The study in this paper can provide a reference for controlling the thermal conductivity of graphene nanoribbons on a certain scale.
【作者单位】：福州大学电气工程与自动化学院;
【基金】：福建省自然科学基金(批准号:2015J01194) 国家自然科学基金(批准号:61174117)资助的课题~~
【分类号】：O551.3

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