Synthesis and Optical Properties of Cu2O and Au-Cu2O core-shell particles

Cuprous oxide (Cu2O) and Au-Cu2O core-shell nanoparticles were successfully synthesized using the chemical reduction method. The morphology of the synthesized pure Cu2Oparticles can be controlled by varying the amount of reducing agent NH2OH.HCl. Due to their similar crystal structure and relatively small lattice mismatch Cu2O particles are nucleated and locally undergo an epitaxial growth on the surface of the multi-faceted Au seed resulting in a stellated icosahedra Au-Cu2O core-shell particle. The extinction spectrum of Cu2O particles offew hundred-nm in size is dominated by light scattering, while that of the stellated icosahedra Au-Cu2O core-shell particles exhibits the interband absorption of the Cu2O shell only. The interband absorption peak undergoes a blue shift as the shell gets thinner. No prominent SPR of the Au nanocore was observed due to a rather thick Cu2O shell.