Bimetallic Network with Hetero‐interfacial Plasmons

Abstract Fabrication of bimetallic networks consisting of periodically arranged gold nanoparticles (AuNPs) embedded with a grid of silver nanowires, where solution‐processing materials or techniques are involved in all of the fabrication procedures, is reported. Annealing of the colloidal gold nanoparticles and the photoreduction of the silver ions in the mixture solution of AgNO₃ and polyvinyl pyrrolidone in water are the main processes. The key to this fabrication is that the AuNP array is used as the mask for the photoreduction of silver ions into nanowires, where the silver nanowires are thus located between the AuNPs. Two sets of dipolar and quadrupolar plasmons, as well as their respectively coupled resonance modes, are observed in the measurements and specified using theoretical analysis. Thus, the bimetallic photonic structures not only show enhanced and extended resonance spectrum due to the overlap of multiple localized surface plasmons but also induce plasmonic hetero‐interfacial interaction between the closely adjacent AuNPs and silver nanowires.