Recent successes in forming different shaped face centered cubic (fcc) metal nanostructures has enabled a greater understanding of nanocrystal growth mechanisms. Here we extend this understanding to the synthesis of hexagonally close packed (hcp) metal nanostructures, to form uniquely faceted ruthenium nanocrystals with a well-defined hourglass shape. The hourglass nanocrystals are formed in a three-step thermodynamic growth process with dodecylamine as the organic stabilizer. The hourglass nanocrystals are then shown to readily self-assemble to form a new type of nanocrystal superlattice.
Watt, J., Yu, C., Chang, L-Y., Cheong, S., & Tilley, R. D. (2013). Shape control from thermodynamic growth conditions: the case of hcp ruthenium hourglass nanocrystals. Journal of the American Chemical Society, 135(2), 606 - 609. https://doi.org/10.1021/ja311366k