Rapid synthesis of high purity gold nanorods via microwave irradiation

A versatile method to rapidly synthesize high quality gold nanorods through the use of a microwave terminated growth process is presented. Traditional nanorod growth procedures require lengthy growth periods in addition to the use of additional materials/steps to terminate growth, including extra reagents, precise control of reagent concentrations, and tuning of environmental factors such as temperature or pH. Utilizing brief, high power microwave irradiation exposure, one can improve the nanorod monodispersity and achieve a significant reduction in the level of nanoparticle impurities within the sub-30 min growth regime without the need of additional reagents or pH adjustments. In addition to the increased synthesis efficiency, microwave-terminated gold nanorods yielded an increase in the longitudinal: transverse plasmon peak ratios, signifying a reduction in nanoparticle impurities with samples treated at 24 min versus traditional 24 h growth procedures without microwave termination. Utilizing the microwave methodology also yields an improved homogeneity of the produced rods as shown with a narrower spectral full width at half maximum compared to traditionally grown gold nanorods.