Molecular-Wires Heterojunction Created by Precise Electrochemical Polymerization

我们首次报道了在单分子尺度的表面上产生的共轭共聚聚合物的可视化。将两种不同类型的噻吩类单体在碘覆盖的金表面进行电化学聚合，可以得到具有不同电子结构的高组装共轭聚合物，其中一部分是低能隙的平面型聚噻吩型聚合物，另一部分是高能带隙的扭曲聚噻吩型聚合物。扫描隧道显微镜(STM)清晰地捕捉到了几种连接类型的快照：双块、三块和多块。共轭共聚物单链在表面表现出异常的摆动运动。这项技术提供了从单分子尺度上理解不同单体的共聚过程的可能性，也提供了利用受控电聚合在表面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.