The ability to create arrays of organic nanostructures with long-range order and uniform size could have applications in electronic and optoelectronic devices. One of the most promising methods for making such arrays is to rely on the self-assembly of molecules on surfaces that already possess long-range order. Researchers at the Swiss Federal Laboratories for Materials Testing and Research in Thun and Liverpool University in the UK have now used this approach to grow ordered arrays of fullerene nanochains on a gold surface, as this image shows.

Gold surfaces are natural templates for growing nanostructures.

Roman Fasel and co-workers sublimated the fullerene molecules onto specially prepared gold substrates that naturally form a rectangular superlattice (J. Phys. Chem. B 110, 21394–21398; 2006). Scanning tunnelling microscopy and low-energy electron diffraction revealed that the nanochains — which each contain just four or five fullerene molecules — only formed at the lower edges of the 'steps' that are found on the gold surface. It is thought that the electron-rich regions near these edges preferentially adsorb the fullerene molecules, which are electron acceptors, leading to the formation of arrays that perfectly reproduce the periodicity of the gold template.