Seed-Mediated Synthesis of Gold Nanorods:  Role of the Size and Nature of the Seed

We report studies on the synthesis of gold nanorods by a three-step seeding protocol method using a variety of different gold seeds. The synthetic method is adapted from one we published earlier (Jana et al. J. Phys. Chem. B 2001, 105, 4065). The seeds chosen for these studies have average diameters in the range from 4 to 18 nm, with positively charged as well as negatively charged surface groups. In all the cases, along with a large concentration of long rods, a small number of different shapes such as triangles, hexagons, and small rods are observed. The proportion of small rods increases with an increase in the seed size used for nanorod synthesis. For long nanorods synthesized by different seeds a…