Fabrication of novel luminor Y2O3:Eu3+ @ SiO2 @ YVO4:Eu3+ with core/shell heteronanostructure

A novel polychromic phosphor with core - shell heteronanostructure has been prepared to improve the chromatic index of phosphors. As for the first example, Y2O3: Eu3+@ SiO2@ YVO4: Eu3+, its synthetic route, structure and optical properties are presented in this paper. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), energy-dispersive x-ray spectra (EDS) and photoluminescence (PL) were all employed to characterize the composite core - shell phosphors. The XRD, FE-SEM and HR-TEM results indicate that the SiO2 and YVO4: Eu3+ layers have been successfully coated on Y2O3: Eu3+ nanoparticles and SiO2 layer, respectively: these layers were further verified by the EDS. The PL showed that the red-emitting phosphor Y2O3: Eu3+@ SiO2@ YVO4: Eu3+ possessed the independent luminescent properties of both the core Y2O3: Eu3+ and the shell YVO4: Eu3+. The emissions were dominated by D-5(0) -> F-7(1) or D-5(0) -> F-7(2) transitions of Eu3+ when excited with different wavelengths. Since this broad-band response to excitation in the range of 225 - 340 nm gave more red/dark red emissions found at 612, 616 and 620 nm, the novel phosphor Y2O3: Eu3+@ SiO2@ YVO4: Eu3+ could have potential biological labeling applications with wide flexibility.