Monodisperse spherical core-shell-structured phosphors obtained by functionalization of silica spheres with Y_2O_3:Eu~(3+) layers for field emission displays

摘要

Spherical SiO_2 particles have been coated with Y_2O_3:Eu~(3+) phosphor layers (SiO_2@Y_2O_3:Eu~(3+)) by a Pechini sol-gel process. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, photoluminescence, and cathodoluminescence spectra were utilized to characterize the SiO_2@ Y_2O_3: Eu~(3+) core-shell-structured phosphor particles. The obtained core-shell phosphors consist of well dispersed submicron spherical particles with narrow size distribution. The thickness of Y_2O_3: Eu~(3+) shell could be easily controlled by changing the number of deposition cycles (60 nm for three deposition cycles). The SiO_2@Y_2O_3:Eu~(3+) core-shell particles show a strong red emission corresponding to ~5D_0-~7F_2 (611 nm) of Eu~(3+) under the excitation of ultraviolet (250 nm) and low-voltage electron beams (2-6 kV), which have potential application for field emission displays.