Measurement of host-to-activator transfer efficiency in nano-crystalline Y2O3:Eu3+ under VUV excitation

We have conducted a systematic study of the excitation and reflectance spectra of nano-crystalline Y2O3:Eu prepared by combustion synthesis. Excitation through the host lattice becomes relatively more efficient as the firing temperature of the precursor is increased, while reflectance properties remain essentially unchanged. Using these data, host-to-activator transfer efficiencies were calculated for excitation at the band edge of Y2O3, and evaluated using a competition kinetics model. From this analysis we conclude that the relatively low luminous efficiency of these materials is due more to poor bulk crystallinity than to surface loss effects.