Spherical SiO₂ @ GdPO₄ : Eu³⁺ Core–Shell Phosphors: Sol–Gel Synthesis and Characterization

Abstract

Nanocrystalline GdPO 4 : Eu 3+ phosphor layers were coated on non-aggregated, monodisperse and spherical SiO 2 particles by Pechini sol–gel method, resulting in the formation of core–shell structured SiO 2 @ GdPO 4 : Eu 3+ particles. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL), low-voltage cathodoluminescence (CL), time-resolved PL spectra and lifetimes were used to characterize the core–shell structured materials. Both XRD and FT-IR results indicate that GdPO 4 layers have been successfully coated on the SiO 2 particles, which can be further verified by the images of FESEM and TEM. Under UV light excitation, the SiO 2 @ GdPO 4 : Eu 3+ phosphors show orange-red luminescence with Eu 3+ 5 D 0 – 7 F 1 (593 nm) as the most prominent group. The PL excitation and emission spectra suggest that an energy transfer occurs from Gd 3+ to Eu 3+ in SiO 2 @ GdPO 4 : Eu 3+ phosphors. The obtained core–shell phosphors have potential applications in FED and PDP devices.