Self-assembly of vertically aligned nanorod supercrystals using highly oriented pyrolytic graphite

Supercrystallization of CdS nanorods (10 nm x 25 nm) into perpendicular superlattices was obtained by controlled evaporation of a nanorod solution trapped between a smooth substrate and a block of highly oriented pyrolytic graphite (HOPG). Hexagonal oriented domains 2 mu m(2) in size were routinely obtained on a variety of substrates without external electric fields.