Structural and Luminescence Properties of Lu2O3:Eu3+ F127 Tri-Block Copolymer Modified Thin Films Prepared by Sol-Gel Method.

Lu2O3:Eu3+ transparent, high density, and optical quality thin films were prepared using the sol-gel dip-coating technique, starting with lutetium and europium nitrates as precursors and followed by hydrolysis in an ethanol-ethylene glycol solution. Acetic acid and acetylacetonate were incorporated in order to adjust pH and as a sol stabilizer. In order to increment the thickness of the films and orient the structure, F127 Pluronic acid was incorporated during the sol formation. Structural, morphological, and optical properties of the films were investigated for different F127/Lu molar ratios (0-5) in order to obtain high optical quality films with enhanced thickness compared with the traditional method. X-ray diffraction (XRD) shows that the films present a highly oriented cubic structure <111> beyond 1073 K for a 3-layer film, on silica glass substrates. The thickness, density, porosity, and refractive index evolution of the films were investigated by means of m-lines microscopy along with the morphology by scanning electron microscope (SEM) and luminescent properties.

Preparation and scintillating properties of Sol-Gel Eu(3+), TB(3+) co-doped Lu(2)O(3) nanopowders.

Nanocrystalline Eu(3+), Tb(3+) co-doped Lu(2)O(3) powders with a maximum size of 25.5 nm were prepared by the sol-gel process, using lutetium, europium and terbium nitrates as precursors, and ethanol as a solvent. Differential thermal analysis (DTA) and infrared spectroscopy (IR) were used to study the chemical changes during the xerogel annealing. After the sol evaporation at 100 °C, the formed gel was annealed from 300 to 900 °C for 30 min under a rich O(2) atmosphere, and the yielded product was analyzed by X-ray diffraction (XRD) to characterize the microstructural behavior and confirm the crystalline structure. The results showed that Lu(2)O(3) nanopowders start to crystallize at 400 °C and that the crystallite size increases along with the annealing temperature. A transmission electron microscopy (TEM) study of samples annealed at 700 and 900 °C was carried out in order to analyze the microstructure, as well as the size, of crystallites. Finally, in regard to scintillating properties, Eu(3+) dopant (5 mol%), Tb(3+) codoped Lu(2)O(3) exhibited a typical red emission at 611 nm (D(°)→(7)F(2)), furthermore, the effect of Tb(3+) molar content (0.01, 0.015 and 0.02% mol) on the Eu(3+) radioluminiscence was analyzed and it was found that the higher emission intensity corresponds to the lower Tb(3+) content.