Formation of bimetallic nanoparticles by pulsed laser ablation of multicomponent thin films in water

Abstract

This study presents results on pulsed laser ablation of metallic and bimetallic thin films immersed in liquids. The thin films are deposited by classical on-axis pulsed laser deposition technology by using targets consisted of one or two sections composed of different metals. Using this technique gold, silver and gold/silver thin films are deposited on quartz substrate. By changing the area of the different sections of the target, thin films with different concentrations of the two metals are obtained. The as prepared films are then placed on the bottom of glass vessel filled with double distilled water and irradiated by nanosecond laser pulses delivered by Nd:YAG laser system operated at λ = 1064 nm. This results in fabrication of colloids composed by metallic and bimetallic nanoparticles. The performed TEM analyses revealed spherical and spherical-like shape of the particles produced. The optical extinction spectra of the obtained colloidal nanoparticles show plasmon excitations as the resonance wavelength can be efficiently tuned in a wide range by changing the ratio of the basic metals in the films.