Laser ablation method: use of surfactants to form the dispersed Ag nanoparticles

The laser ablation method was employed to synthesize Ag nanoparticles. With the aid of the surfactants, SDS and CTAB, highly dispersed Ag particles were attained. Using a laser intensity of 120 mJ/pulse particle diameters of 4.2±1.9 nm were produced in SDS and 7.8±4.5 nm in CTAB. The anionic SDS and cationic CTAB exhibited differential ability in protecting Ag colloids: the particles containing SDS remained stable at least one month, while the CTAB-protected Ag precipitated completely within one week. Plausible explanations were given to such stability observations. Moreover, the changes in the ablation laser powers were found to achieve particle size control. Lesser laser intensity of 60 mJ/pulse produced larger particle sizes of 6.8±2.7 nm and 9.4±5.9 nm in SDS and CTAB, respectively.