Fabrication of Asymmetric Molecular Junctions by the Oriented Assembly of Dithiocarbamate Rectifiers
Fabrication of Asymmetric Molecular Junctions by the Oriented Assembly of Dithiocarbamate Rectifiers
复制标题
DOI：
10.1021/ja110244j
复制
发表时间：
2011-04-20
影响因子：
15
通讯作者：
von Wrochem, Florian
中科院分区：
文献类型：
--
作者：
Gao, Deqing;Scholz, Frank;von Wrochem, Florian
金属分子在金属表面的定向组装是平面金属-分子-金属结整流的要求。在这里，我们展示了如何利用二硫代氨基甲酸酯和硫代乙酸酯锚基之间的吸附动力学差异来形成不对称分子的定向组装，这些不对称分子通过二硫代氨基甲酸酯部分与金结合。然后，将游离的硫代乳酸基团用作配体，与金纳米颗粒结合，形成所需的金属-分子-金属连接。除了允许与电极的不对称耦合外，分子还表现出不对称的分子主干，其中将电极与中心的对位取代苯环分开的烷基链的长度相差两个亚甲基单元。在整个结制作过程中，用光电子能谱、红外光谱和扫描隧道显微镜对各层进行了表征。在汞滴电极和自组装单层之间使用导电聚合物夹层的大面积连接证明了电学数据和分子结构之间的关系。
The oriented assembly of molecules on metals is a requirement for rectification in planar metal-molecule-metal junctions. Here, we demonstrate how the difference in adsorption kinetics between dithiocarbamate and thioacetate anchor groups can be utilized to form oriented assemblies of asymmetric molecules that are bound to Au through the dithiocarbamate moiety. The free thioactate group is then used as a ligand to bind Au nanoparticles and to form the desired metal-molecule-metal junction. Besides allowing an asymmetric coupling to the electrodes, the molecules exhibit an asymmetric molecular backbone where the length of the alkyl chains separating the electrodes from a central, para-substituted phenyl ring differs by two methylene units. Throughout the junction fabrication, the layers were characterized by photoelectron spectroscopy, infrared spectroscopy, and scanning tunneling microscopy. Large area junctions using a conducting polymer interlayer between a mercury-drop electrode and the self-assembled monolayer prove the relationship between electrical data and molecular structure.