Facile preparation of SERS-active nanostructured Au spheres by simple reduction of [formula omitted] ions with EDOT

Abstract

Uniform submicron-scale Au spheres with an average dimension of 574nm were facilely prepared from the redox reaction between HAuCl4 and 3,4-ethylenedioxythiophene (EDOT) in aqueous solution under ambient conditions. HAuCl4 precursor readily polymerized to poly(3,4-ethylenedioxythiophene) (PEDOT) and metallic Au spheres simultaneously formed within a short period of time. The Au spheres are consisted of two slightly different types of spherical particles based on their surface textures. Major raspberry-like Au spheres are formed through the assembly of very tiny Au nanoparticles, while minor rosette-like Au spheres are formed through the dense packing of Au nanoplates. Both Au spheres are pure metallic face-centered cubic Au based on X-ray photoelectron spectroscopy and powder X-ray diffraction. The resultant Au spheres are adequate for application to surface-enhanced Raman scattering (SERS) due to their rough surfaces and nanogaps on the surfaces. Both methylene blue and crystal violet molecules were detectable at concentrations as low as 10−7M.