title: Seeded growth of monodisperse gold nanorods using bromide-free surfactant mixtures.
abstract: We demonstrate for the first time that monodisperse gold nanorods (NRs) with broadly tunable dimensions and longitudinal surface plasmon resonances can be synthesized using a bromide-free surfactant mixture composed of alkyltrimethylammonium chloride and sodium oleate. It is found that uniform gold NRs can be obtained even with an iodide concentration approaching 100 μM in the growth solution. In contrast to conventional wisdom, our results provide conclusive evidence that neither bromide as the surfactant counterion nor a high concentration of bromide ions in the growth solution is essential for gold NR formation. Correlated electron microscopy study of three-dimensional structures of gold NRs reveals a previously unprecedented octagonal prismatic structure enclosed predominantly by high index {310} crystal planes. These findings should have profound implications for a comprehensive mechanistic understanding of seeded growth of anisotropic metal nanocrystals.
authors.affiliation: Department of Chemistry, University of Pennsylvania, Pennsylvania 19104, USA.
authors.forename: Xingchen
authors.initials: X
authors.lastname: Ye
authors.forename: Yuzhi
authors.initials: Y
authors.lastname: Gao
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Danielle C
authors.initials: DC
authors.lastname: Reifsnyder
authors.forename: Chen
authors.initials: C
authors.lastname: Zheng
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Murray
mesh_terms: D001965:Bromides / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D001965:Bromides; D013501:Surface-Active Agents; D006046:Gold