Synthesis and optical properties of nanosized powders: lanthanide-doped Y O 2 3

Y1.8Nd0.2O3 and Y1.8Er0.2O3 powder samples were prepared by combustion synthesis. X-ray diffraction showed that the materials are nanostructured, with average coherence length 5–10 nm. The visible and infrared luminescence spectra of nanometric cubic Y1.8Nd0.2O3 and Y1.8Er0.2O3 show some important differences from those of the bulk materials. In the case of Y1.8Er0.2O3, faster relaxation of some excited states occurs, leading to changes in the relative intensities of several optical transitions. As far as nanostructured Y Nd O is concerned, the 4F ª41.8 0.2 3 3r2 I9r2 transition is characterized by a perturbed intensity pattern of the Stark components and by an anomalous integrated intensity. Possible explanations for this behaviour are proposed. q1999 Elsevier Science B.V. All rights reserved.