Tailoring surface plasmon resonance in Ag:ZrO2 nanocomposite thin films

Ag:ZrO2 nanocomposite thin films have been synthesized by a modified sol–gel technique. The effect of post-deposition treatments i.e. thermal annealing and UV irradiation on micro-structural, chemical and optical properties of nanocomposite thin films have been studied by a transmission electron microscope, X-ray photoelectron spectrophotometer and UV–vis spectrophotometer. Films deposited with a polymeric ZrO2 sol containing Ag+ ions when treated with either thermal annealing or with UV irradiation exhibit formation of Ag:ZrO2 nanocomposite thin films via decomposition of Ag2O3 into metallic Ag. The formed Ag nanoparticles are found predominantly in spherical shape and density of Ag nanoparticles increases with increase in annealing duration for a particular concentration of Ag precursor. A protocol is provided to tailor the surface plasmon resonance-induced absorption peak at wavelength from 454 to 586 nm. These nanocomposite thin films show saturable absorption and exhibit high value of non-linear absorption coefficient.