Vaezi Mehran, Nejat Pishkenari Hossein, Nemati Alireza
Institute for Nanoscience and Nanotechnology (INST), Sharif University of Technology, Tehran, Iran.
Institute for Future, Qingdao University, Qingdao, China.
J Chem Phys. 2020 Dec 21;153(23):234702. doi: 10.1063/5.0029490.
Newly synthesized nanocars have shown great potential to transport molecular payloads. Since wheels of nanocars dominate their motion, the study of the wheels helps us to design a suitable surface for them. We investigated C thermal diffusion on the hexagonal boron-nitride (h-BN) monolayer as the wheel of nanocars. We calculated C potential energy variation during the translational and rotational motions at different points on the substrate. The study of the energy barriers and diffusion coefficients of the molecule at different temperatures indicated three noticeable changes in the C motion regime. C starts to slide on the surface at 30 K-40 K, slides freely on the boron-nitride monolayer at 100 K-150 K, and shows rolling motions at temperatures higher than 500 K. The anomaly parameter of the motion reveals that C has a diffusive motion on the boron-nitride substrate at low temperatures and experiences superdiffusion with Levy flight motions at higher temperatures. A comparison of the fullerene motion on the boron-nitride and graphene surfaces demonstrated that the analogous structure of the graphene and hexagonal boron-nitride led to similar characteristics such as anomaly parameters and the temperatures at which the motion regime changes. The results of this study empower us to predict that fullerene prefers to move on boron-nitride sections on a hybrid substrate composed of graphene and boron-nitride. This property can be utilized to design pathways or regions on a surface to steer or trap the C or other molecular machines, which is a step toward directional transportation at the molecular scale.
新合成的纳米车已显示出运输分子载荷的巨大潜力。由于纳米车的轮子主导其运动，对轮子的研究有助于我们为它们设计合适的表面。我们研究了作为纳米车轮子的六方氮化硼（h-BN）单层上的C热扩散。我们计算了分子在基底上不同点的平移和旋转运动过程中的C势能变化。对不同温度下分子的能垒和扩散系数的研究表明，C的运动状态有三个显著变化。C在30 K - 40 K时开始在表面滑动，在100 K - 150 K时在氮化硼单层上自由滑动，在高于500 K的温度下呈现滚动运动。运动的异常参数表明，C在低温下在氮化硼基底上具有扩散运动，在高温下经历具有列维飞行运动的超扩散。对富勒烯在氮化硼和石墨烯表面的运动进行比较表明，石墨烯和六方氮化硼的类似结构导致了类似的特征，如异常参数和运动状态变化的温度。这项研究的结果使我们能够预测，富勒烯更喜欢在由石墨烯和氮化硼组成的混合基底上的氮化硼部分移动。这一特性可用于在表面设计路径或区域，以引导或捕获C或其他分子机器，这是迈向分子尺度定向运输的一步。
