Monodisperse and core-shell structured SiO2-Lu2O3:Ln3+ (Ln=Eu, Tb, Dy, Sm, Er, Ho, and Tm) spherical particles: A facile synthesis and luminescent properties

The core-shell structured SiO2-Lu2O3:Ln3+ particles were realized by coating the Lu2O3:Ln3+ phosphors onto the surface of non-aggregated, monodisperse and spherical SiO2 particles by the Pechini sol–gel method. The as-synthesized products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray (EDX) spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), photolumiminescence (PL), and low-voltage cathodoluminescence (CL). The results indicate that the 800 °C annealed sample consists of crystalline Lu2O3 shells and amorphous SiO2 cores, in spherical shape with a narrow size distribution. The as-obtained particles show strong light emission with different colors corresponding to different Ln3+ ions under ultraviolet–visible light excitation and low-voltage electron beams excitation, which have potential applications in fluorescent lamps and field emission displays. - Graphical Abstract: Representative SEM and TEM images of the core-shell structured SiO2-Lu2O3:Eu3+ particles; CIE chromaticity diagram showing the emission colors for SiO2-Lu2O3:Ln3+; Multicolor emissions of SiO2-Lu2O3:Ln3+ particles. Highlights: ► The core-shell particles were realized by coating the phosphors onto the surface of SiO2 particles. ► The sample consists of crystalline Lu2O3 shells and amorphous SiO2 cores. ► The particles show different light emission colors corresponding to Ln3+ ions. ► They have potential applications in fluorescent lamps and field emission displays.