Nanoscale Templating of Close-Packed C60 Nanowires

Abstract

Close-packed C60 wires were prepared on Cu(110)-(2 × 1)-O reconstructed surface composed of nearly perfect (2 × 1)-O domains cut by occasional bare Cu(110) regions. By controlling the oxygen dosage, the bare Cu regions are forced to assume single atomic width separating the adjacent oxide domains by 0.76 nm, a distance comparable to the hard-sphere diameter of C60 molecules. When dosed at elevated temperature, C60 molecules preferably “fall into” metallic Cu troughs and grow into C60 wires along the 〈001〉 direction, with an average nearest-neighbor distance of 1.07 ± 0.02 nm. The C60−C60 intermolecular interaction causes the energy of the HOMO and LUMO+1 to shift down by 30 ∼ 40 meV with respect to single molecules. This simple templating method may be applicable to self-assembly of single molecule wires of other fullerenes and other organic molecules, opening the way to address the electron transport in 1-D supramolecular assemblies.