PREPARATION AND FLUORESCENCE SPECTROSCOPY OF BULK MONOCLINIC EU3+Y2O3AND 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 syn thesis method. The bulk monoclinic phase has sharp spectral lines with out the line broadening and ''secondary phase'' of Eu2+:Y2O3 nanocryst als. The unusual optical properties of site A in this material have be en determined to be intrinsic to the monoclinic phase and are not a re sult of surface effects in the nanocrystals. The D-5(0) fluorescence l ife-times are longer in the nanocrystals than in the bulk material, in dicating that there is no lifetime shortening in the nanocrystals due to quenching by the proximity of surface defects.