Structural and spectroscopic properties of silver nanoparticles prepared by laser ablation in different aqueous solutions

Silver spherical shape nanoparticles have been fabricated by Nd-YAG pulsed laser ablation of a 99.99% silver target in two types of solution: deionized water and aqueous solutions of trisodium citrate. The temporal evolution of the prepared silver nanoparticles (AgNPs) was studied through different time stages extended between 0 and 15 min of ablation time and through studying the effect of aging on these AgNPs over a period of 1 to 10 days by the end of laser ablation. The silver characteristic nanoparticles surface plasmon resonances (SPR) peak was investigated and analyzed by UV-Visible absorption spectroscopy (UV-Vis). Absorption spectra of the laser ablated solutions clearly indicate that silver nanoclusters have been formed during the ablation duration. Scanning electron microscope (SEM) images also confirmed that the size and shape of the AgNPs are dependent on the aqueous medium and the length of ablation time. The laser ablation of silver in trisodium citrate solution produces well-separated, spheroidal, non-aggregated and stable AgNPs with time. Modifications of particles size and aggregation were also investigated for samples prepared in deionized water. Our research reveals the basic mechanism of silver laser ablation in water and aqueous trisodium citrate solution and offers an easy well controlled method to fabricate silver nanoparticles.