Manipulation of optical properties of Ag/Cu alloy nanowire arrays embedded in anodic alumina membranes

Arrays of Ag/Cu alloy nanowires embedded in anodic alumina membranes (AAMs) were synthesized by directly electrodepositing from a mixing electrolyte solution containing Ag⁺ and Cu²⁺ ions. Manipulations of optical properties of the resulting samples were successfully achieved by tuning the molar ratio of Ag⁺ and Cu²⁺ ions in the starting materials. When the ratio is less than 2:20, two surface plasma resonance (SPR) peaks corresponding to Ag and Cu appear, respectively. After annealing treatment, the SPR peak corresponding to Cu disappears, and that of Ag presents a red shift. Furthermore, this red shift can be up to 85 nm when the molar ratio of Ag⁺ and Cu²⁺ reduce to 1:20, which is attributed to the transferable electrons from Cu atoms.