Seed-Mediated Growth of Gold Nanorods: Limits of Length to Diameter Ratio Control

摘要

The effects of the seed reaction conditions on the two-step seed-mediated growth of gold nanorods and the effect of gold and reducing agent content in the growth solution were evaluated. Results indicate that the reaction conditions used to produce the seeds have a significant impact on the aspect ratio of the gold nanorods produced. Increasing the concentration of gold or the reaction temperature in the seed production step results in lower length to diameter (aspect ratio) gold rods. In addition, the amount of prepared seed added to the growth solution impacts the rod aspect ratio, with increasing amounts of seed reducing the aspect ratio. The effects of reducing agent, ascorbic acid (AA), and gold content of the growth solution on the aspect ratio of the produced rods are strongly interrelated. There exists a minimum ascorbic acid to gold concentration below which rods will not form; however, increasing the ratio above this minimum results in shorter rods being formed. Characterization of nanorod growth is performed by UV-vis-NIR spectrophotometry and transmission electron microscopy (TEM).