Oyamada Nobuaki, Minamimoto Hiro, Murakoshi Kei
Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan.
J Am Chem Soc. 2022 Feb 16;144(6):2755-2764. doi: 10.1021/jacs.1c12213. Epub 2022 Feb 2.
For the motion control of individual molecules at room temperature, optical tweezers could be one of the best approaches to realize desirable selectivity with high resolution in time and space. Because of physical limitations due to the thermal fluctuation, optical manipulation of small molecules at room temperature is still a challenging subject. The difficulty of the manipulation also emerged from the variation of molecular polarizability depending on the choice of molecules as well as the molecular orientation to the optical field. In this article, we have demonstrated plasmonic optical trapping of small size molecules with less than 1 nm at the gap of a single metal nanodimer immersed in an electrolyte solution. electrochemical surface-enhanced Raman scattering measurements prove that a plasmonic structure under electrochemical potential control realizes not only the selective molecular condensation but also the formation of unique mixed molecular phases which is distinct from those under a thermodynamic equilibrium. Through detailed analyses of optical trapping behavior, we established the methodology of plasmonic optical trapping to create the novel adsorption isotherm under applying an optical force at electrified interfaces.
对于室温下单个分子的运动控制，光镊可能是在时间和空间上以高分辨率实现理想选择性的最佳方法之一。由于热涨落导致的物理限制，室温下小分子的光学操纵仍然是一个具有挑战性的课题。操纵的困难还源于分子极化率随分子选择以及分子相对于光场方向的变化。在本文中，我们展示了在浸入电解质溶液的单个金属纳米二聚体的间隙处对尺寸小于1nm的小分子进行等离子体光捕获。电化学表面增强拉曼散射测量证明，在电化学势控制下的等离子体结构不仅实现了选择性分子凝聚，还形成了与热力学平衡下不同的独特混合分子相。通过对光捕获行为的详细分析，我们建立了等离子体光捕获方法，以在带电界面施加光力时创建新的吸附等温线。
