Department of Materials Science and Engineering, Izmir Institute of Technology, Izmir 35430, Turkey.
Nanotechnology. 2016 Aug 19;27(33):335601. doi: 10.1088/0957-4484/27/33/335601. Epub 2016 Jul 5.
We report the controlled self-organization and switching of newly designed Schiff base (E)-4-((4-(phenylethynyl) benzylidene) amino) benzenethiol (EPBB) molecules on a Au (111) surface at room temperature. Scanning tunneling microscopy and spectroscopy (STM/STS) were used to image and analyze the conformational changes of the EPBB molecules. The conformational change of the molecules was induced by using the STM tip while increasing the tunneling current. The switching of a domain or island of molecules was shown to be induced by the STM tip during scanning. Unambiguous fingerprints of the switching mechanism were observed via STM/STS measurements. Surface-enhanced Raman scattering was employed, to control and identify quantitatively the switching mechanism of molecules in a monolayer. Density functional theory calculations were also performed in order to understand the microscopic details of the switching mechanism. These calculations revealed that the molecular switching behavior stemmed from the strong interaction of the EPBB molecules with the STM tip. Our approach to controlling intermolecular mechanics provides a path towards the bottom-up assembly of more sophisticated molecular machines.
我们报告了在室温下，新设计的席夫碱（E）-4-（（4-（苯乙炔基）亚苄基）氨基）苯硫醇（EPBB）分子在 Au（111）表面上的受控自组装和切换。扫描隧道显微镜和光谱学（STM/STS）用于对 EPBB 分子的构象变化进行成像和分析。通过增加隧道电流，用 STM 针尖诱导分子的构象变化。在扫描过程中，STM 针尖被显示可以诱导分子的域或岛的切换。通过 STM/STS 测量观察到了切换机制的明确指纹。表面增强拉曼散射被用于控制和定量识别单层中分子的切换机制。还进行了密度泛函理论计算，以了解切换机制的微观细节。这些计算表明，分子的切换行为源于 EPBB 分子与 STM 针尖的强烈相互作用。我们控制分子间力学的方法为更复杂的分子机器的自下而上组装提供了一条途径。
