Sol–gel preparation and characterization of uniform core-shell structured LaInO 3:Sm 3+/Tb 3+@SiO 2 phosphors

Abstract

The core-shell structured LaInO 3:Ln 3+@SiO 2 (Ln 3+ = Sm 3+, Tb 3+) phosphors were realized by coating LaInO 3:Ln 3+ phosphors on the surface of silica microspheres via a modified Pechini sol–gel process. The phase, structure, morphology, and fluorescent properties of the materials were well characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform IR spectroscopy (FT-IR), photoluminescence (PL) spectra, cathodoluminescence (CL) spectra, and the kinetic decays, respectively. The results reveal that the obtained core-shell structured phosphors consist of amorphous silica core and crystalline LaInO 3:Ln 3+ shell, which keep the uniform spherical morphology of pure silica spheres with narrow size distribution. Upon excitation by ultraviolet (UV) irradiation or electron beam, the phosphors show the characteristic emission lines of Sm 3+ ( 4G 5/2– 6H 5/2,7/2,9/2, orange) in LaInO 3:Sm 3+@SiO 2 and characteristic emissions of Tb 3+ ( 5D 4– 7F 6,5,4,3, green) in LaInO 3:Tb 3+@SiO 2, respectively. This kind of phosphors may have potential applications in field emission displays (FEDs) based on their uniform shape, low-cost synthetic route, and diverse luminescent properties.