Nanostructured lanthanide-doped Lu2O3 obtained by propellant synthesis

Lu(1.98)Ln(0.02)O(3) (Ln = Nd, Eu, and Er) powders obtained by propellant synthesis were characterized using XRD, SAXS, TEM, and SEM. Samples have a very porous, open morphology with fractal scaling properties. The building blocks of the fractal aggregates are 60-90 nm lanthanide-doped cubic LU2O3 crystalline particles, which exhibit changes in the lattice parameter proportional to the lanthanide ionic radius. The NIR luminescence spectrum of nanocrystalline Lu2O3:Nd3+ was measured and emission was observed from the F-4(3/2) excited state to the I-4(J) (9/2, 11/2, 13/2, 15/2) state. The spectral features are very similar to those of a bulk material of identical composition prepared for comparison, though with a noticeable difference in the relative intensity of the F-4(3/2) --> I-4(9/2) and F-4(3/2) --> I-4(9/2) transitions. The spectroscopic-quality parameter (X) for nanocrystalline samples was calculated and was found to be higher than for the bulk.