title: Sol-gel fabrication and photoluminescence properties of SiO2 @ Gd2O3:Eu3+ core-shell particles.
abstract: A uniform nanolayer of europium-doped Gd2O3 was coated on the surface of preformed submicron silica spheres by a Pechini sol-gel process. The resulted SiO2 @ Gd2O3:Eu3+ core-shell structured phosphors were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), photoluminescence (PL) spectra as well as kinetic decays. The XRD results show that the Gd2O3:Eu3+ layers start to crystallize on the SiO2 spheres after annealing at 400 degrees C and the crystallinity increases with raising the annealing temperature. The core-shell phosphors possess perfect spherical shape with narrow size distribution (average size: 640 nm) and non-agglomeration. The thickness of the Gd2O3:Eu3+ shells on the SiO2 cores can be adjusted by changing the deposition cycles (70 nm for three deposition cycles). Under short UV excitation, the obtained SiO2@Gd2O3:Eu3+ particles show a strong red emission with 5D0-7F2 (610 nm) of Eu3+ as the most prominent group. The PL intensity of Eu3+ increases with increasing the annealing temperature and the number of coating cycles.
authors.affiliation: Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
authors.forename: G Z
authors.initials: GZ
authors.lastname: Li
authors.forename: M
authors.initials: M
authors.lastname: Yu
authors.forename: Z L
authors.initials: ZL
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Lin
authors.forename: R S
authors.initials: RS
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Fang
mesh_terms: D003460:Crystallization / Q000379:methods*; D005063:Europium / Q000737:chemistry* / Q000528:radiation effects; D005682:Gadolinium / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D049449:Luminescence; D008163:Luminescent Measurements / Q000379:methods*; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods; D010316:Particle Size; D044367:Phase Transition; D010777:Photochemistry / Q000379:methods*; D012822:Silicon Dioxide / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D005063:Europium; C030581:gadolinium oxide; D012822:Silicon Dioxide; D005682:Gadolinium