Effect of Laser Fluence on the Characteristics of Ag Nanoparticles Produced by Laser Ablation

6-12 nm silver nanoparticles were synthesized by the pulsed laser ablation of a high purity silver bulk in distilled water. Effect of laser fluence on the size, morphology and structure of produced nanoparticles has been studied experimentally. Pulses of a Q-switched Nd:YAG laser of 1064 wavelength at 7 ns pulse width at different fluences were employed to irradiate the silver target in water. The UV-Visible absorption spectra of the Ag nanoparticles exhibit surface plasmon resonance absorption peak in the UV region. TEM and SEM micrographs, in a good agreement with DLS results, indicate that with increasing the laser fluence the average size of spherical Ag nanoparticles is decreased. It is found that Ag nanoparticles exhibit photoluminescence emission with two peaks because of the inter band transition and electron-hole recombination.