| 引用本文: | 冉迪,郑鹏,苑泽伟,王宁.基底化学吸附对石墨烯机械裁剪性能的影响机制*[J].中国表面工程,2023,36(5):179~189 |
| RAN Di,ZHENG Peng,YUAN Zewei,WANG Ning.Influence Mechanism of Substrate Chemisorption on Mechanical Cutting Properties of Graphene[J].China Surface Engineering,2023,36(5):179~189 |
|
| 摘要: |
| 机械裁剪法是简单高效制备石墨烯纳米带的加工方法，目前对基底化学吸附如何影响石墨烯机械裁剪行为的认识尚有不足。为探究基底化学吸附对石墨烯机械裁剪性能的影响机制，基于 ReaxFF 反应力场和 Verlet 算法，采用反应分子动力学方法对 Ni、Pt、Cu 金属基底上的石墨烯机械裁剪行为展开研究，根据纳米压痕和机械裁剪中探针与石墨烯（CT-CG）、石墨烯层内（CG-CG）、石墨烯与基底（CG-M）间键合数量和键合强度的变化规律，分析基底化学吸附对键合性能和石墨烯机械裁剪行为的影响。结果表明：Ni、Pt、Cu 基底对石墨烯的化学吸附能力依次减弱，强化学吸附作用增大了 CG-M 键合强度， 促进了 CT-CG 键合，削弱了 CG-CG 键合强度，降低了石墨烯的抗破损强度，Ni、Pt、Cu 基底上的石墨烯抗破损强度分别为 110.19、121.71、176.53 GPa。强化学吸附使石墨烯发生了大面积撕裂破损，弱化学吸附使石墨烯仅发生了部分碳链和碳原子的剥离。强化学吸附基底提高了石墨烯的机械裁剪效率，减小了机械裁剪深度，降低了探针下压载荷，提高了探针对石墨烯的摩擦力，提高了石墨烯的机械裁剪性能。基于反应分子动力学方法可深入探究基底化学吸附对石墨烯机械裁剪性能的影响规律及内在机理，研究结果可为不同化学吸附基底条件下高效、高精度石墨烯纳米带的机械裁剪提供理论依据。 |
| 关键词: 金属基底 化学吸附 石墨烯 机械裁剪 分子动力学 |
| DOI：10.11933/j.issn.1007?9289.20221113001 |
| 分类号:TH164 |
| 基金项目:国家自然科学基金（52275455）；辽宁省教育厅科学研究经费（LJGD2020003，LJKZ0160）资助项目 |
|
| Influence Mechanism of Substrate Chemisorption on Mechanical Cutting Properties of Graphene |
|
RAN Di1,2, ZHENG Peng1, YUAN Zewei1, WANG Ning3
|
|
1.School of Mechanical Engineering, Shenyang University of Technology, Shenyang 110870 , China;2.School of Mechanical Engineering, Shenyang Urban Construction University, Shenyang 110167 , China;3.Engineering Training Center, Shenyang University of Technology, Shenyang 110870 , China
|
| Abstract: |
| Graphene nanoribbons with different directions and widths can adjust the zero-energy bandgap of graphene, allowing wide use of graphene in nano-semiconductor devices. Mechanical cutting is a simple and efficient method for preparing graphene nanoribbons. Most current studies assume that the substrate surface and graphene involve physical adsorptions; however, many substrate surfaces involve chemisorption with graphene in actual mechanical cutting. The effect of substrate chemisorption on the mechanical cutting behavior of graphene is not fully understood. This paper investigates the influence mechanism of substrate chemisorption on the mechanical cutting properties of graphene. Based on the ReaxFF reaction potential function and the Verlet algorithm, the mechanical cutting behavior of graphene on Ni, Pt, and Cu metal substrates was studied through reactive molecular dynamics. The effect of substrate chemisorption on bond properties was analyzed according to the bond number and bond strength between tip and graphene (CT-CG), graphene layers (CG-CG), and graphene and substrate (CG-M) in nanoindentation. Graphene mechanical cutting depth was determined according to the friction and wear mechanism by oblique scratching. The mechanical cutting depth was used to scratch the graphene, intuitively revealing the influence mechanism of substrate chemisorption on the mechanical cutting properties of graphene through the bond changes between the tip, substrate, and graphene. The results show that the chemisorption capacities of Ni, Pt, and Cu substrate to graphene were decreased in turn. A strong chemisorption substrate increased the CG-M bond strength and CT-CG bond strength, weakened the CG-CG bond strength, and greatly reduced the breakage strength of graphene. The breakage strengths of graphene on Ni, Pt, and Cu substrates were 110.19 GPa, 121.71 GPa, and 176.53 GPa, respectively, in mechanical cutting. The graphene under the tip center was at the highest stress and most susceptible to breakage. The decrease in CG-CG bond strength promoted the chemical reactivity of graphene and increased CT-CG bond strength. The downward pressure of the tip induced CG-M bonding, weakened CG-CG bond strength, and induced CT-CG bonding. The coupling effect of strong chemisorption of the substrate and downward tip pressure made graphene more easily breakable in mechanical cutting. CG-M bonding occurred before the tip scratching process on the Ni substrate; strong chemisorption reduced the overall CG-CG bond strength of graphene, increased the CT-CG bond number, increased the cutting edge angle of the tip, caused graphene folding and piling on the Ni substrate, and caused extensive graphene tearing and damage. CG-M bonding only occurred in the tip scratching path on the Pt substrate. CG-CG bond strength reduction only occurred in the tip scratching path; graphene outside of the tip scratching path maintained high CG-CG bond strength. A weakened chemisorption capacity caused only partial carbon chain stripping of graphene on the Pt substrate. No CG-M bonding occurred during the tip scratching process on the Cu substrate. All graphene maintained high CG-CG bond strength; only the CG-CG bond strength under the graphene tip was reduced by downward pressure of the tip. Greatly weakened chemisorption caused only partial carbon atom stripping of graphene on the Cu substrate. Graphene on the Pt and Cu substrates was not folded and piled. In summary, strong chemisorption of the substrate improves the mechanical cutting efficiency of graphene, reduces the mechanical cutting depth, reduces the downward tip pressure, increases the tip friction, and improves the mechanical cutting performance. The chemisorption of the substrate changes the bond region, quantity, and strength of CT-CG, CG-CG, and CG-M bonds, and changes the mechanical cutting properties of graphene. The influence and internal mechanism of substrate chemisorption on the mechanical cutting properties of graphene were thoroughly investigated using the reaction molecular dynamics method. This research provides a theoretical basis for preparing graphene nanoribbons by mechanical cutting with high efficiency and high precision in different chemisorption substrate conditions. |
| Key words: metal substrate chemisorption graphene mechanical cutting molecular dynamics |
