Short aspect ratio gold nanorods prepared using gamma radiation in the presence of cetyltrimethyl ammonium bromide (CTAB) as a directing agent

The synthesis of short aspect ratio gold nanorods using gamma radiation method by incorporating cetyltrimethyl ammonium bromide (CTAB) as a directing agent is reported in this communication. The radiolysis of Au⁺, in the presence of 2.5 nm Au seeds and 0.1 mol dm^?3 isopropanol, results in the formation of Au spheres as evident from surface plasmon resonance band at 527 nm. However, by carrying out radiolysis at lower radiation dose rate, short aspect gold nanorods having surface plasmon bands at 513 and 670 nm have been prepared. The formation of rods at low radiation dose rate was observed to be governed by the kinetics of particle growth. The TEM of as-synthesized nanoparticles confirmed the formation of uniform sized nanorods having an aspect of 2.4.