Fabrication of Cu@Ag core-shell nanoparticles for nonlinear optical applications

We report the preparation of the core-shell structured Cu@Ag nanoparticles by a simple wet chemical route at room temperature. The surface plasmon resonance band at 405 nm is indicative of the formation of Cu@Ag nanoparticles. The powder X-ray diffraction and energy dispersive X-ray analyses were carried out to elucidate the structure and chemical composition respectively. The morphological investigations made by electron microscopes revealed that the particles are spherical in shape with core-shell structures having size of about 50 nm. The X-ray photoelectron spectroscopy was performed to elucidate surface state composition of the core-shell structured nanoparticles based on the binding energies and confirmed the formation of Cu@Ag core-shell nanoparticles. The enhanced non-linear optical response of the Cu@Ag core-shell nanoparticles was demonstrated by z-scan experiment using He-Ne laser. This report provides a simple, economical and practical technology to fabricate Cu@Ag core-shell nanoparticles with enhanced nonlinear optical properties.