摘要
通过原子力显微镜高度曲线确定高度分别为0.57 nm、0.90 nm和1.30 nm三个石墨烯片,随后进行多次力-距离曲线测量。结果发现:三个石墨烯片吸附力数值的平均值分别为0.30 nN、0.32 nN和0.34 nN,脱附力的平均值分别为5.33 nN、5.66 nN和7.24 nN。实验显示吸、脱附力随石墨烯厚度的增加单调递增,表明测量力-距离曲线可能成为一种判断石墨烯厚度的方法。为解释不同厚度石墨烯片力-距离曲线,构建铂基底与单、双和三层石墨烯相互作用的共格界面模型,采用第一性原理模拟方法对模型界面分离功和界面电荷转移进行计算。结果发现三个模型界面分离功分别为10.0 eV·nm^(-2)、10.4 eV·nm^(-2)和10.8 eV·nm^(-2),石墨烯片越厚界面分离功越大,计算结果与实验结果中吸附力数值变化趋势相同。
Relation between graphene thickness and its force-distance curve is studied with atomic force microscope and first-principles calculations. Firstly, we located relatively smooth graphene sheets with atomic force microscope line-profile, and got three graphene samples with thickness of 0.57 nm, 0.90 nm and 1.30 nm. Then, we tested force-distance curves of the samples with multiple measurements. It shows that average value of adsorption forces of the samples are 0.30 nN, 0.32 nN and 0.34 nN, and the average value of desorption forces are 5.33 nN, 5.66 nN and 7.24 nN, respectively. It shows that both adsorption and desorption forces are increased with the increasing of graphene thickness, which implies that it could be an alternative method to measure thickness of graphene with force-distance curves provided by AFM. In order to explain the experimental result, we built platinum-graphene coherent interface models by combining Pt with one, two and three graphene layers, and calculated interface separation work with first-principles calculation. Simulation results showed that the interface separation work for the models are 10.0 eV·nm^(-2), 10.4 eV·nm^(-2) and 10.8 eV·nm^(-2), respectively. It is consistent with the trend of adsorption forces in experiment.
作者
房勇
金永中
陈建
宗洪祥
张丽英
FANG Yong;JIN Yongzhong;CHEN Jian;ZONG Hongxiang;ZHANG Liying(Material Corrosion and Protection Key Laboratory of Sichuan Province,Sichuan University of Science and Engineering,Zigong,Sichuan 643000,China;State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi'an,Shaanxi 710049,China;Key Laboratory of Clean Energy Materials Chemistry of Guangdong Higher Education Institutes,Lingnan Normal University,Zhanjiang,Guangdong 524048,China)
出处
《计算物理》
CSCD
北大核心
2021年第4期441-446,共6页
Chinese Journal of Computational Physics
基金
材料腐蚀与防护四川省重点实验室(2020CL15,2020CL20)
四川轻化工大学人才引进项目(2017RCL34)资助。
关键词
石墨烯厚度
原子力显微镜
力-距离曲线
第一性原理
graphene thickness
atomic force microscope
force-distance curve
first-principles
作者简介
第一作者:房勇(1983-),讲师,博士,研究方向为多尺度计算机模拟,E-mail:fangyong@suse.edu.cn;通信作者:陈建,E-mail:wuhangzs@163.com。
