Kinetic Regulation of the Synthesis of Pentatwinned Gold Nanorods below Room Temperature

• Published in: Journal of physical chemistry. C 2021-11, Vol.125 (43), p.23937-23944
• Main Authors: Sánchez-Iglesias, Ana, Jenkinson, Kellie, Bals, Sara, Liz-Marzán, Luis M
• Format: Article
• Language: English
• Subjects: C: Spectroscopy and Dynamics of Nano, Hybrid, and Low-Dimensional Materials
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.1c07284

The synthesis of gold nanorods requires the presence of symmetry-breaking and shape-directing additives, among which bromide ions and quaternary ammonium surfactants have been reported as essential. As a result, hexadecyltrimethyl­ammonium bromide (CTAB) has been selected as the most efficient surfactant to direct anisotropic growth. One of the difficulties arising from this selection is the low solubility of CTAB in water at room temperature, and therefore the seeded growth of gold nanorods is usually performed at 25 °C or above, which has restricted so far the analysis of kinetic effects derived from lower temperatures. We report a systematic study of the synthesis of gold nanorods from pentatwinned seeds using hexadecyltrimethyl­ammonium chloride (CTAC) as the principal surfactant and a low concentration of bromide as shape-directing agent. Under these conditions, the synthesis can be performed at temperatures as low as 8 °C, and the corresponding kinetic effects can be studied, resulting in temperature-controlled aspect ratio tunability.