Luminescent gold–poly(thiophene) nanoaggregates prepared by one-step oxidative polymerization

Abstract

We report the facile synthesis, formation mechanism, and photoluminescent (PL) properties of gold–poly(thiophene) (Au–PTh) nanoaggregates. They were prepared by one-step oxidative polymerization, in which Au³⁺ ion was utilized as an oxidizing agent for the polymerization of thiophene. Transmission electron microscopy (TEM) and high-resolution TEM (HR-TEM) analyses demonstrated that the ‘raspberry-like’ Au–PTh nanoaggregates consist of individual Au NPs covered by PTh and stabilized by Tween 80. For Au–PTh nanoaggregates, a clear red shift in the SP peak was observed in the UV absorption spectra as compared with pristine Au nanoparticles (NPs). This red shift of the SP band is a consequence of the location of π-conjugated PTh on the surface of Au NPs, resulted from a strong binding between sulfur atoms of PTh and the Au NPs (sulfur–gold interaction). The strong interaction between the gold and sulfur atoms of PTh in the Au–PTh nanoaggregates was observed by X-ray photoelectron spectroscopy (XPS) analysis. The SP effect contributes to the PL intensity enhancement of the Au–PTh nanoaggregates and was confirmed by confocal laser scanning microscopy (CLSM).