Structure transition and enhanced photoluminescence of Gd2-xYxO3:Eu nanocrystals

The influence of Y doping on the crystallization behavior, structure transition and the photoluminescence enhancement of Gd2O3:Eu (Eu3+ doping concentration is kept as 10%) nanocrystals prepared by combustion method was investigated. The as-prepared Gd2O3: Eu was in monoclinic phase. As x increased to 0. 14, cubic phase could be observed as well as monoclinic, and heavy Y doping (x > 0.40) changed the structure to cubic instead of monoclinic. Though it was prominent that cubic Y2O3:Eu, as the extreme case of Y substitution, had much stronger photoluminescence than monoclinic Gd2O3:Eu in a same Eu3+-doping concentration, it is quite surprising that less Y doping increased the emission of monoclinic Gd2O3:Eu. This effect can be ascribed to the crystal field difference induced by lattice distortion, which is a much more significant behavior for the nanocrystals than the bulk. (C) 2003 Elsevier Science (USA). All rights reserved.