关键词: SiO₂@SrAl₂Si₂O₈∶Eu²⁺, 核-壳结构, 溶胶-凝胶法, 蓝色荧光体

Abstract: Nanocrystalline SrAl₂Si₂O₈∶Eu²⁺ phosphor layers were coated on non-aggregated, mono-dispersed, and spherical SiO₂ particles by sol-gel process at relatively low temperature, resulting in the formation of core-shell SiO₂@SrAl₂Si₂O₈∶Eu²⁺ particles. X-ray diffraction, scanning electron microscope (SEM), transmission electron microscope (TEM), as well as photoluminescence were utilized to characterize the core-shell structured SiO₂@SrAl₂Si₂O₈∶Eu²⁺ particles. XRD analysis confirms the formation of SiO₂@SrAl₂Si₂O₈∶Eu²⁺ particles, it indicates that the SrAl₂Si₂O₈∶Eu²⁺ phosphor layers coated on SiO₂ particles are hexagonal crystal phase. SEM and TEM indicate that the roughness of the SiO₂ particles’ surface obviously increases. The obtained core-shell phosphors consist of well dispersed submicron spherical particles with a narrow size distribution, and the thickness of coated layers is about 20-30nm. The core-shell particles show strong blue emission, which is ascribed to transition from 5d to 4f (around 440nm) of Eu²⁺ under the excitation of ultraviolet light (361nm). The excitation and emission spectra show that Eu²⁺ can be incorporated into SrAl₂Si₂O₈ effectively. The study of optical properties suggest that these particles may be used in plasma display panel (PDP) device and other luminescent apparatus.

Key words: SiO₂@SrAl₂Si₂O₈∶Eu²⁺, core-shell structure, sol-gel process, blue phosphor