Improving the Electrical Conductivity of Carbon Nanotube Networks: A First-Principles Study

• DOI: 10.1021/nn2032227
• Publication Date: 2011-11-07T20:15:22Z
• Authors: Elise Y. Li; Nicola Marzari
• Keywords: Models, Molecular; Metal; Nanotubes, Carbon; carbon nanotube networks; Electric Conductivity; Structural Characterization; 02 engineering and technology; transition metals; Chemistry; Wannier Functions; Complexes; Models, Chemical; first-principles calculations; Transparent; quantum conductance; Chemical Functionalization; Computer Simulation; Catalyst; Particle Size; 0210 nano-technology; Electrodes; Films

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.