Huang Yingying, Li Hanlin, Zhu Liuyuan, Song Yongshun, Fang Haiping
School of Physics, East China University of Science and Technology, Shanghai 200237, China.
School of Physics, Zhejiang University, Hangzhou 310027, China.
Nanomaterials (Basel). 2024 Oct 2;14(19):1593. doi: 10.3390/nano14191593.
Ripples on graphene play a crucial role in manipulating its physical and chemical properties. However, producing ripples, especially at the nanoscale, remains challenging with current experimental methods. In this study, we report that tiny ripples in graphene can be generated by the adsorption of a single metal cation (Na, K, Mg, Ca, Cu, Fe) onto a graphene sheet, based on the density functional theory calculations. We attribute this to the cation-π interaction between the metal cation and the aromatic rings on the graphene surface, which makes the carbon atoms closer to metal ions, causing deformation of the graphene sheet, especially in the out-of-plane direction, thereby creating ripples. The equivalent pressures applied to graphene sheets in out-of-plane direction, generated by metal cation-π interactions, reach magnitudes on the order of gigapascals (GPa). More importantly, the electronic and mechanical properties of graphene sheets are modified by the adsorption of various metal cations, resulting in opened bandgaps and enhanced rigidity characterized by a higher elastic modulus. These findings show great potential for applications for producing ripples at the nanoscale in graphene through the regulation of metal cation adsorption.
石墨烯上的波纹在调控其物理和化学性质方面起着至关重要的作用。然而，利用当前的实验方法来产生波纹，尤其是在纳米尺度上，仍然具有挑战性。在本研究中，基于密度泛函理论计算，我们报告了单个金属阳离子（钠、钾、镁、钙、铜、铁）吸附到石墨烯片上可产生微小的波纹。我们将此归因于金属阳离子与石墨烯表面芳香环之间的阳离子-π相互作用，这种相互作用使碳原子更靠近金属离子，导致石墨烯片变形，尤其是在面外方向，从而产生波纹。由金属阳离子-π相互作用在面外方向施加到石墨烯片上的等效压力达到吉帕斯卡（GPa）量级。更重要的是，各种金属阳离子的吸附改变了石墨烯片的电学和力学性质，导致带隙打开且刚性增强，其特征为具有更高的弹性模量。这些发现显示出通过调控金属阳离子吸附在石墨烯中产生纳米级波纹的应用潜力巨大。
