Optical and electrical characterization of samaria-doped ceria

Ce0.8SM0.2O1.9 and CeO2 nanomaterials were prepared by a solution technique to produce an ultrafine particulate material with high sinterability. In this work, the structural characteristics, the photoluminescent behavior and the ionic conductivity of the synthesized materials are focused. The thermally decomposed material consists of less than 10 nm in diameter nanoparticles. The Raman spectrum of pure CeO2 consists of a single triple degenerate F-2g model characteristic of the fluorite-like structure. The full width at half maximum of this band decreases linearly with increasing calcination temperature. The photoluminescence spectra show a broadened emission band assigned to the ligand-to-metal charge-transfer states O -> Ce4+. The emission spectra of the Ce0.8Sm0.2O1.9 specimens present narrow bands arising from the 4G(5/2) -> H-6(J) transitions (J = 5/2, 7/2, 9/2 and 11/2) of Sm3+ ion due to the efficient energy transfer from the O -> Ce4+ transitions to the emitter 4G(5/2) level. The ionic conductivity of sintered specimens shows a significant dependence on density. (C) 2009 Elsevier B.V. All rights reserved.