Optical properties of Copper-Copper oxide core-shell nanoparticles

The Cu- CuO core-shell nanoparticles were synthesized by pulsed laser ablation (PLA) from metallic target in water. SEM, TEM and EDX techniques were used to characterize the morphology, structure and size of nanoparticles as well as chemical composition. The absorption spectrum of copper nanoparticles in water showed a broad shoulder about 630 nm, and after 2 weeks, the CuO or Cu2O shells with about 25 nm diameter were observed around copper nanoparticles and so contemporary peak wavelength was shifted to blue. In this case variation of the shell’s diameter during time caused change in value of "m eff. It was found for the Cu nanoparticles that the value of "m eff decreased with time. We found rather good agreement between the experimental results and the calculation based on Mie’s theory.

Keywords:

optical , copper , copper oxide , core-shell”