Gamma-irradiation-induced Ag/SiO2 composite films and their optical absorption properties

Abstract Small Ag particles or clusters dispersed mesoporous SiO 2 composite films were prepared by a new method: First the matrix SiO 2 films were prepared by sol–gel process combined with the dip-coating technique, then they were soaked in AgNO 3 solutions followed by irradiation of γ-ray at room temperature and in ambient pressure. The structures of these films were examined by X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), and optical absorption spectroscopy. It has been shown that the Ag particles grown within the porous SiO 2 films are very small, and they are isolated and dispersed from each other with very narrow size distributions. With increasing the soaking concentration and an additional annealing, an opposite peakshift effect of the surface plasmon resonance (SPR) was observed in the optical absorption measurements.