Ordered self-assembling of tetrahedral oxide nanocrystals

Self-assembling of size, shape, and phase controlled nanocrystals into superlattices with translational and even orientational ordering is a new approach For engineering nanocrystal materials and devices. High purity tetrahedral nanocrystals of CoO, with edge lengths of 4.4 +/- 0.2 nm, were synthesized and separated from Co nanocrystals, using a novel magnetic field phase-selection technique. Self-assembling of the faceted CoO nanocrystals forms ordered superlattices, the structures of which are determined.