Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
ACS Nano. 2011 Dec 27;5(12):9726-36. doi: 10.1021/nn2032227. Epub 2011 Nov 17.
We address the issue of the low electrical conductivity observed in carbon nanotube networks using first-principles calculations of the structure, stability, and ballistic transport of different nanotube junctions. We first study covalent linkers, using the nitrene-pyrazine case as a model for conductance-preserving [2 + 1] cycloadditions, and discuss the reasons for their poor performance. We then characterize the role of transition-metal adsorbates in improving mechanical coupling and electrical tunneling between the tubes. We show that the strong hybridization between the transition-metal d orbitals with the π orbitals of the nanotube can provide an excellent electrical bridge for nanotube-nanotube junctions. This effect is maximized in the case of nitrogen-doped nanotubes, thanks to the strong mechanical coupling between the tubes mediated by a single transition metal adatom. Our results suggest effective strategies to optimize the performance of carbon nanotube networks.
我们使用第一性原理计算研究了不同碳纳米管连接点的结构、稳定性和弹道传输，解决了碳纳米管网络中观察到的低电导率问题。我们首先研究了共价连接物，以氮烯-吡嗪的情况作为保持电导的[2+1]环加成反应的模型，并讨论了它们性能不佳的原因。然后，我们描述了过渡金属吸附物在改善管间机械耦合和电子隧穿方面的作用。我们表明，过渡金属 d 轨道与碳纳米管的π轨道之间的强杂化可以为碳纳米管-碳纳米管连接点提供优异的电桥。在氮掺杂纳米管的情况下，这种效应最大化，这要归功于单个过渡金属原子吸附体介导的纳米管之间的强机械耦合。我们的结果表明了优化碳纳米管网络性能的有效策略。
