Synthesis of Cu/SiO 2 composite films via gamma-irradiation route and their optical absorption properties

Abstract

The Cu 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, and then they were soaked in Cu(NO 3) 2 solutions followed by γ-ray irradiation at room temperature and in ambient pressure. Thus, the prepared Cu/SiO 2 composite films were examined by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and optical absorption spectroscopy. It has been shown that the Cu 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 the Cu particles size changing, an interesting peak shift was observed in the optical absorption measurement. Possible mechanisms of this behavior are discussed in this paper.