Optical and magnetic properties of Cu/SiO2 composite films prepared via γ-irradiation route

In the present radiolytic study, we report the formation of Cu+2 ions in a sol–gel SiO2 thin film via γ-irradiation. The optical and magnetic properties of Cu/SiO2 film are discussed in relation to the mechanism of the formation of Cu+2 ions through irradiation. The color of the treated Cu/SiO2 films swinging from faint green to dark blue as the concentration of Cu(NO3)2 solution was increased from 0.2 to 0.6 and then decreased at 1.2 mol/L. The absorption spectra of the samples revealed many identified broad absorption bands in both, UV (∼190–280 nm) and, in the visible region (∼360–530 and ∼600–740 nm) beside a shallow broad ones in near infrared (∼800–880 nm). Also, there are remarkable increases in the absorption intensities accompanying with red shift for the heat-treated samples soaked in 1.2 mol/L. In order to study the state of Cu2+, and confirm the influence of the matrix, by investigating their EPR and XRD spectroscopy, respectively.