Preparation and Fluorescence Spectroscopy of Bulk Monoclinic Eu3+:Y2O3 and Comparison to Eu3+:Y2O3 Nanocrystals

We report the laser spectroscopic characterization of bulk monoclinic Eu3+:Y2O3, which was prepared by a high-temperature, high-pressure synthesis method. The bulk monoclinic phase has sharp spectral lines without the line broadening and “secondary phase” of Eu3+:Y2O3 nanocrystals. The unusual optical properties of site A in this material have been determined to be intrinsic to the monoclinic phase and are not a result of surface effects in the nanocrystals. The 5D0 fluorescence lifetimes are longer in the nanocrystals than in the bulk material, indicating that there is no lifetime shortening in the nanocrystals due to quenching by the proximity of surface defects.