Fluorescent-magnetic nanocrystals: synthesis and property of YPxV1−xO4:Eu@GdPO4 core/shell structure

Abstract

A fluorescent-magnetic YP_xV_1−xO₄:Eu@GdPO₄ core/shell nanostructure was prepared by a two-step method. The YP_xV_1−xO₄:Eu core was synthesized using a hydrothermal method, and it exhibits strong photoluminescence with the effective doping of phosphorus (P) and europium (Eu) into a YVO₄ matrix. The hydrothermal process provides a hydrophilic and fresh surface for coating GdPO₄ shell. As YP_xV_1−xO₄:Eu and GdPO₄ have the similar unit cell parameters, YP_xV_1−xO₄:Eu nanoparticles (NPs) were favorably coated by an epitaxial growth of GdPO₄ shell in aqueous phase. The core/shell nanostructure was identified by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The GdPO₄ shell not only possesses the paramagnetic character, but also enhances the photoluminescence efficiency by blocking the non-radiative de-excitation from the VO₄³⁻groups to the surface quenching sites. These optical and magnetic properties promise outstanding fluorescent-magnetic bifunctional nanomaterials.