Preparation, X-ray analysis and spectroscopic investigation of nanostructured Lu2O3:Tb

Formation of Lu2O3 through combustion of Lu(NO3)(3) and CO(NH2)(2) (urea) at various temperatures was investigated. From XRD patterns analysis, the optimal reaction temperature was found to be similar to 600-700 degreesC. For that range products with crystallites of similar to7-13 nm were obtained, as found from TEM pictures. With the same technique Tb-doped Lu2O3 was successfully fabricated and its basic spectroscopic properties were characterized. Emission of the phosphors was found to be typical for Tb3+, with main components at 490 and 550 nm, resulting from radiative relaxation of D-5(4) level. Undoped material produced broad-band luminescence peaking in blue. Raw Tb-doped samples were brownish, which was attributed to incorporation of some of the activator as Tb4+. Such assignment was derived from reflection, excitation and EPR spectra. The colour could be completely removed through post-fabrication vacuum heat-treatment at 1100 degreesC. (C) 2001 Elsevier Science B.V. All rights reserved.