Oligoyne Single Molecule Wires
Oligoyne Single Molecule Wires
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DOI：
10.1021/ja9061129
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发表时间：
2009-11-04
影响因子：
15
通讯作者：
Lambert, Colin J.
中科院分区：
文献类型：
--
作者：
Wang, Changsheng;Batsanov, Andrei S.;Lambert, Colin J.
我们利用金 - 分子 - 金（Au | molecule | Au）结构的扫描隧道显微镜 - 分子断裂结技术，报道了寡炔分子线Py - (C≡C)$_n$-Py（n = 1、2和4；Py = 4 - 吡啶基）在单分子水平的电导。电导直方图显示出多组峰，这归因于吡啶基头部基团与金电极之间不同的接触几何结构。实验和理论证据都表明，较高电导的基团与吡啶基在更高配位点（如台阶边缘或金吸附原子旁边）的吸附有关。寡炔系列中的所有三个电导基团都显示出极低的β值，为(0.06 ± 0.03) Å⁻¹，也就是说，电导几乎与分子长度无关。在相同条件下研究的4,4'-联吡啶并不遵循这种指数衰减规律。结合密度泛函理论和非平衡格林函数形式理论的理论计算支持了实验结果。我们得出结论，寡炔和聚炔是一类非常有前途的可集成到电子电路中的分子线。
We report the electrical conductance at the single molecule level of the oligoyne molecular wires Py-(C C)(n)-Py (n = 1, 2 and 4; Py = 4-pyridyl) using STM-molecular break junction techniques in Au vertical bar molecule vertical bar Au configurations. The conductance histograms reveal multiple series of peaks attributed to differing contact geometries between the pyridyl head groups and the gold electrodes. Both experimental and theoretical evidence point to the higher conduction groups being related to adsorption of the pyridyl group at more highly coordinated sites such as step edges or alongside gold adatoms. All three conduction groups in the oligoyne series show a remarkably low beta value of (0.06 +/- 0.03) angstrom(-1), that is, the conductance is almost independent of molecular length. 4,4'-Bipyridyl studied under the same conditions does not follow this exponential decay series. Theoretical calculations using a combination of density functional theory and nonequilibrium Green's function formalism support the experimental results. We conclude that oligoynes and polyynes are a very promising class of molecular wires for integration into electronic circuitry.