Molecular-Wires Heterojunction Created by Precise Electrochemical Polymerization

我们报告了在单分子尺度表面上产生的共轭共聚物的首次可视化。将两种不同的噻吩单体在碘包覆的金表面进行电化学聚合，可以制备出具有不同电子结构的高组装共轭共聚物，其中一部分是具有低能隙的扁平多噻吩，另一部分是具有高能隙的扭曲多噻吩。扫描隧道显微镜（STM）清楚地捕捉到几种连接类型的快照：二块、三块和多块。单链共轭共聚物在表面表现出反常的摆动运动。该技术提供了在单分子尺度上理解不同单体共聚过程的可能性，也提供了在受控电聚合的表面上构建单分子超晶格的可能性。

We report a first visualization of conjugated copolymers which are produced on surfaces with a single-molecular scale. Electrochemical polymerization of two different kinds of thiophene monomers on an iodine-covered gold surface could create the highly assembled conjugated copolymers with different electronic structures in which one part is a flattened polythiophene with low energy gap while other part is a twisted one with high energy gap. Scanning tunneling microscope (STM) clearly captured the snapshots of several linkage types: diblock, triblock and multiblock. Single strand of conjugated copolymers exhibited an anomalous swinging motion on surface. This technique presents the possibility of understanding the copolymerization process from the different monomers with a single-molecular scale, and also building a single-molecular superlattice on a surface using controlled electropolymerization.