Luminescent-plasmonic effects in GdPO4:Eu3+ nanorods covered with silver nanoparticles

Abstract

Luminescent-plasmonic, core/shell type GdPO4:Eu3+/SiO2/NH2/Ag nanomaterials, with elongated, rod-like morphology were successfully synthesized. The Eu3+-doped GdPO4 nanorods prepared via hydrothermal synthesis route were surface modified by coating with amine modified silica shell. The as-prepared luminescent core/shell nanostructures were impregnated with AgNO3 solution, followed by Ag+→Ag° reduction with NaBH4 solution, forming small silver nanoparticles (NPs) attached to the external silica shell. The obtained multifunctional nanomaterials showed simultaneously bright red emission, under UV light irradiations and plasmonic activity originating from the surface Ag NPs. The plasmonic phase influenced on spectroscopic properties of the products, altering the shape of the excitation and emission spectra (changing bands intensity and their ratio), as well as shortening the emission lifetimes of the Eu3+ ion. The products synthesized were characterized by the following techniques: powder X-ray diffraction (XRD); transmission electron microscopy (TEM); energy dispersive X-ray analysis (EDX); UV–vis absorption spectroscopy; luminescence spectroscopy, i.e. measurements of excitation and emission spectra, and luminescence decay curves.