Structural versus Electrical Functionalization of Oligo(phenylene ethynylene) Diamine Molecular Junctions
Structural versus Electrical Functionalization of Oligo(phenylene ethynylene) Diamine Molecular Junctions
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DOI：
10.1021/jp506078a
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发表时间：
2014-09-18
影响因子：
3.7
通讯作者：
Agrait, Nicolas
中科院分区：
文献类型：
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作者：
Teresa Gonzalez, M.;Zhao, Xiaotao;Agrait, Nicolas
我们从实验和理论两方面探讨了当一系列官能团加入到低聚（苯乙烯）（OPE）二胺线中时，基于该线的分子结的电导和填充。利用扫描隧道显微镜断结（STM BJ）技术，我们在两种环境（空气和1,2,4-三氯苯）中研究了这些化合物，并探索了不同的起始分子浓度。我们表明，分子结的电导率在不同化合物之间表现出差异，这在标准浓度下是显著的，但在足够低的浓度下就变得不重要了。这表明，官能团的主要作用是影响分子线的包装，而不是改变其电性能。我们的理论计算一致地预测，由于官能团的电子结构，金属丝的电导率没有显著变化，尽管它们在OPE主链内阻碍环旋转的能力可以在更高的填充密度下导致更高的电导率。
We explore both experimentally and theoretically the conductance and packing of molecular junctions based on oligo(phenyleneethynylene) (OPE) diamine wires, when a series of functional groups are incorporated into the wires. Using the scanning tunnelling microscopy break-junction (STM BJ) technique, we study these compounds in two environments (air and 1,2,4-trichlorobenzene) and explore different starting molecular concentrations. We show that the electrical conductance of the molecular junctions exhibits variations among different compounds, which are significant at standard concentrations but become unimportant when working at a low enough concentration. This shows that the main effect of the functional groups is to affect the packing of the molecular wires, rather than to modify their electrical properties. Our theoretical calculations consistently predict no significant changes in the conductance of the wires due to the electronic structure of the functional groups, although their ability to hinder ring rotations within the OPE backbone can lead to higher conductances at higher packing densities.