Synthesis and Characterization of Spherical SiO₂@Y₂O₃: Eu Core-Shell Composite Phosphors

Abstract

The monodisperse spherical SiO 2 particles were overcoated with Y 2 O 3 : Eu 3+ phosphor layers via a Pechini sol-gel process and the resulting SiO 2 @Y 2 O 3 : Eu 3+ core-shell phosphors were subsequently annealed at 800 o C at an ambient atmosphere.The crystallographic structure, morphology, and luminescent property of core-shell structured SiO 2 @Y 2 O 3 :Eu 3+ phosphors were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and photoluminescence (PL).The spherical, nonagglomerated SiO 2 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 2 O 3 : Eu 3+ phosphors.The core-shell structured SiO 2 @Y 2 O 3 : Eu 3+ phosphors showed a strong red emission, which was dominated by the 5 D 0 -7 F 2 transition (610 nm) of Eu 3+ ion under the ultraviolet excitation (263 nm).The PL emission properties of SiO 2 @Y 2 O 3 : Eu 3+ phosphors were also compared with pure Y 2 O 3 : Eu 3+ nanophosphors.