The effect of AgNO3 concentration on formation of Ag nanoparticles in Sol-Gel derived Ag-SiO2 thin films

In this investigation, Ag-SiO2 thin films with different concentrations of Ag (0.2, 0.4, 1.6 and 8%) has been fabricated on soda-lime glass substrate using sol-gel method. After an annealing process, physical and chemical properties of the deposited silica films containing Ag nanoparticles have been studied including optical, topographical structural, morphological and size of the nanoparticle as well as their distribution using UV-visble spectrophotometery, atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques, respectively. Based on our data analysis, the Ag nanoparticles did not form in the samples with low (0.2%) and high Ag concentrations (8%), without any suitable annealing process. Instead, the nanoparticles were formed easily for the intermediate Ag concentrations. In fact, for the the low and high Ag concentration, the Ag nanoparticles formed at the annealing temperature of 200 o C. In addition, according to TEM observations, the minimum average size of the synthesized particles were determined about 4 hm for the thin films containing 0.2% Ag concentration.