Preparation and characterization of rare-earth-doped Y2O3 luminescent ceramics by the use of reverse micelles

The objective of this project was to study luminescent powders of Y2O3:Eu3+ (5 at%), Y2O3:Tb3+ (5 at%), and Y2O3:Tm3+,Yb3+ (Tm: 2 at%, Yb: 1 at%), prepared by the use of reverse micelles. This report describes the phase stability, crystallite size, and luminescence properties of these powder materials as a function of heat treatment time and temperature. The Y2O3 phase produced during synthesis can be controlled by the heat treatment temperature and time. Monoclinic and cubic phases of Y2O3 are obtainable, with the monoclinic powders produced at the smaller crystallite sizes. Photoluminescence properties of the Y2O3:Eu3+ and Y2O3:Tb3+ were evaluated and sharp emission was observed for the Eu3+ powders at 610 nm and the Tb3+ powders at 544 nm. The maximum emission intensity of both phosphors increased as annealing temperature and time increased. This, however, was not seen for the case of the Y2O3:Tm3+,Yb3+ powders, which exhibited emission at 454 nm. For this phosphor, as heat treatment temperature increased the luminescence intensity decreased.