Luminescent and structural analysis of yttrium oxide doped with different percentages of terbium and dysprosium, to obtain different shades of green to yellow

摘要

The structural and luminescent results of nondoped, terbium and dysprosium doped, and codoped Y2O3 powders are presented. Different percentages of the rare earth ions were employed. The powders were obtained by means of the solvent evaporation technique and were annealed at 1100 degrees C for 2 h. The emission spectra of these samples are associated with the characteristic intraelectronic energy levels that are related to the Tb3+ and Dy3+ ions transitions. The maximum peaks of emission are located at 542 nm with lambda(exc) = 274 nm for terbium that is associated with the D-5(4) to F-7(5) transition; for dysprosium, the maximum is at 573 nm, when excited with lambda(exc) = 210 nm, corresponding to the F-4(9/2) to H-6(13/2) transition; the emission spectra of the Y2O3 : Tb4% : Dy3% and Y2O3 : Tb4% : Dy0.75% phosphors were also obtained, and the emissions of these two ions are observed when excited with lambda(exc) = 260 nm, suggesting that these ions are near neighbors, giving place to energy transfer between these two ions. When the sample of Y2O3 : Tb(3+ )is excited with lambda(exc) = 274 nm, a single exponential decay is observed with tau = 2.95 ms; when the Y2O3 : Dy3+ is excited with lambda(exc) = 210 nm, there is decay time with tau = 0.89 ms; and when excited with lambda(exc) = 274 nm, the phosphors of Y2O3 : Tb3+ : Dy3+ also have a single exponential decay with tau = 2.04 ms. The Commission Internationale de l'Eclairage diagram coordinates obtained for different relative contents of these lanthanide ions are given. X-ray diffraction analyses of these phosphors indicate a polycrystalline cubic yttrium oxide structure with a grain size running from 37 to 45 nm. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)