Effect of focusing conditions and laser parameters on the fabrication of gold nanoparticles via laser ablation in liquid

The generation of nanoparticles using pulsed laser ablation has inherent advantages compared to conventional methods, like the purity and stability of the fabricated nanoparticles, aerosols and colloids. This study addresses the influence of laser parameters such as laser fluence, laser wavelength as well as focusing condition of laser beam on the size and morphology of the gold nanoparticles prepared in de-ionized water by pulsed laser ablation. The optimum conditions at which gold nanoparticles are obtained with controllable average size have been reported as these parameters affected the size, distribution and absorbance spectrum. The effect of laser fluence was studied. The laser fluences were divided into three regions (low, middle and high). A noteworthy change was observed at each region. At low fluences, the size of the nanoparticles decreases as the fluence increases to a certain critical value after which the size of the nanoparticles increases as the fluence increases. Also a significant change in the size distribution of the gold nanoparticles was noticed during the variation of the focusing conditions at gold-water interface. (C) 2012 Elsevier Ltd. All rights reserved.