Nanoscale Templating of Close-Packed C₆₀ Nanowires

Abstract

Close-packed C 60 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 C 60 molecules. When dosed at elevated temperature, C 60 molecules preferably “fall into” metallic Cu troughs and grow into C 60 wires along the 〈001〉 direction, with an average nearest-neighbor distance of 1.07 ± 0.02 nm. The C 60 −C 60 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.