Block Copolymer Templated Anisotropic Plasmonic Nanostructure

The anisotropic nanostructures of noble metals are of great interest for plasmonic applications due to their narrow-band localized surface plasmon resonance and larger local field enhancement. This work reports a simple and promising fabrication method of anisotropic gold (Au) nanostructures film using poly (styrene-b-2-vinylpyridine (PS-b-P2VP) block copolymers (BCP) as template. In this process, PS-b-P2VP spherical micelles were first synthesized as template followed by selective deposition of Au compound HAuCl₄ inside P2VP core of the micelles. Subsequently, heat treatment of the Au deposited BCP films followed by complete removal of the BCP template produced edged gold nanostructures of various shapes with a dependence on the annealing temperature and time. Moreover, optical extinction spectra showed presence of signature near infra-red peaks of anisotropic Au nanostructure, suggesting its potential for applications in plasmonic devices.