In Situ Gap-Mode Raman Spectroscopy on Single-Crystal Au(100) Electrodes: Tuning the Torsion Angle of 4,4′-Biphenyldithiols by an Electrochemical Gate Field
In Situ Gap-Mode Raman Spectroscopy on Single-Crystal Au(100) Electrodes: Tuning the Torsion Angle of 4,4′-Biphenyldithiols by an Electrochemical Gate Field
复制标题
DOI：
10.1021/ja2020185
复制
发表时间：
2011-05-18
影响因子：
15
通讯作者：
Wandlowski, Thomas
中科院分区：
文献类型：
--
作者：
Cui, Li;Liu, Bo;Wandlowski, Thomas
采用Au(100)|4,4'-联苯二硫醇（BPDT）|Au- np （55 nm）夹芯组件，在电化学环境下在单晶金电极上获得了原位间隙模式拉曼光谱。这种几何结构使得研究应用电化学栅场对纳米结构象变化的影响成为可能，例如分子的扭转角（phi）。建立了4,4′- bpdt型分子结中强度比I-C=C/ICring-S与cos(2) phi之间的线性关系，并利用该关系估计了“柔性”分子M1在不同电位下扭转角的电位依赖性。后者随着电位（电荷）变得更负而减少，导致更好的pi-pi耦合，这与增强的结电导有关。所展示的光谱电化学策略以及光谱结果与（单）分子电导研究的直接相关性可以指导在新型纳米器件中潜在应用的功能分子的选择和阐明。
In situ gap-mode Raman spectra were acquired in an electrochemical environment on a single-crystal gold electrode employing a Au(100)|4,4'-biphenyldithiol (BPDT)|Au-NP(55 nm) sandwich assembly. This geometry enabled an investigation of the influence of an applied electrochemical gate field on the conformational changes in nanojunctions, such as the torsion angle (phi) of molecules. A linear correlation between the intensity ratio I-C=C/ICring-S and cos(2) phi in 4,4'-BPDT-type molecular junctions was established and subsequently utilized to estimate the potential dependence of the torsion angle of the "flexible" molecule M1 at different potentials. The latter decreases as the potential (charge) becomes more negative, resulting in better pi-pi coupling, which correlates with enhanced junction conductance. The demonstrated spectroelectrochemical strategy and the direct correlation of the spectroscopic results with (single) molecular conductance studies may guide the selection and elucidation of functional molecules for potential applications in novel nanodevices.