以杂原子取代的共轭稠环分子[并四噻吩(Th4)、并四呋喃(Ox4)和并四吡咯(Py4)]为研究模型,利用密度泛函理论结合非平衡态格林函数方法,研究了杂原子取代和分子端基导电连接方式对电子输运行为的影响.结果表明,并四聚体中电子输运行为主要与电子传输路径和量子干涉效应有关.端基连接方式决定了分子中电子的主要传输路径.所考察的模型中存在2条电子传输通道:(1)单双键连接的共轭碳链;(2)由杂原子参与,同相邻碳原子构成的电子传输通道.杂原子的引入构筑了额外的电子传输通道,增强了分子的导电能力.由于并四聚体 α-位连接的T-type体系中存在有效电子传递路径,杂原子仅起到修饰作用.而 β-位连接的C-type体系中缺乏有效电子传输路径,但杂原子通过局域的量子干涉效应对电子传递效率产生显著影响.%A series of poly heterocyclic compounds were selected as the models, and density functional theory together with non-equilibrium Green ' s function method was used to investigate the transport behavior modulated by the doping and linkage position. The results demonstrated that the difference in the transport be-havior is originated from the electron transfer pathway and the quantum interference. In particular, the linkage position on the molecule dominates the main pathway of electron transfer, and the introduction of hetero-atoms establishes extra channels, improving the molecular conductivity. The α-connection in the system provides effi-cient electron transfer pathway, therefore, the hetero-atoms play only a minor role. On the contrary, no effi-cient pathway exists in the system with the β-connection, therefore, the hetero-atoms make contribution to the electron transport through quantum interference effect.
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