Monodisperse spherical core-shell structured SiO2–CaTiO3:Pr3+ phosphors for field emission displays

Abstract

Nanocrystalline CaTiO3:Pr3+ phosphor layers were coated on nonaggregated, monodisperse, and spherical SiO2 particles by the sol-gel method, resulting in the formation of core-shell structured SiO2–CaTiO3:Pr3+ particles. X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, photoluminescence, cathodoluminescence spectra, as well as lifetimes were utilized to characterize the core-shell structured SiO2–CaTiO3:Pr3+ phosphor particles. The obtained core-shell structured phosphors consist of well dispersed submicron spherical particles with a narrow size distribution. The thickness of the CaTiO3:Pr3+ shell could be easily controlled by changing the number of deposition cycles (about 70nm for four deposition cycles). The core-shell SiO2–CaTiO3:Pr3+ particles show a strong red emission corresponding to D21–H43 (612nm) of Pr3+ under the excitation of ultraviolet (326nm) and low voltage electron beams (1–5kV). These particles may be used in field emission displays.