Synthesis and characterization of spherical SiO2@Y 2O3: Eu core-shell composite phosphors

Abstract

The monodisperse spherical SiO2 particles were overcoated with Y2O3: Eu3+ phosphor layers via a Pechini sol-gel process and the resulting SiO2@Y2O3: Eu3+ core-shell phosphors were subsequently annealed at 800°C at an ambient atmosphere. The crystallographic structure, morphology, and luminescent property of core-shell structured SiO2@Y 2O3:Eu3+ phosphors were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence (PL). The spherical, nonagglomerated SiO2 particles prepared by a Stober method exhibited a relatively narrow size distribution in the range of 260-300 nm. The thickness of phosphor shell layer in the core-shell particles can be facilely controlled by varying the coating number of Y 2O3: Eu3+ phosphors. The core-shell structured SiO2@Y2O3: Eu3+ phosphors showed a strong red emission, which was dominated by the 5D0- 7F2 transition (610 nm) of Eu3+ion under the ultraviolet excitation (263 nm). The PL emission properties of SiO 2@Y2O3: Eu3+ phosphors were also compared with pure Y2O3: Eu3+ nanophosphors.