Enhancement of cathodoluminescence intensities of Y2O3:Eu and Gd2O3:Eu phosphors by incorporation of Li ions

Li-doped Y2O3:Eu and Gd2O3:Eu phosphors have been studied as potential red phosphors for application to field emission displays. These phosphors showed cathodoluminescence increases when Li ions are doped. It is found that the lattice of Gd2O3:Eu phosphors transforms from monoclinic to cubic as the Li ions are doped. However, Y2O3:Eu phosphors keep their cubic phases upon Li doping. Also, this investigation has determined that the differences in intensity ratios originate from two different luminescent sites in each phosphor. From this study, it is understood that Li ions affect the luminescence of the Gd2O3:Eu phosphor by influencing its lattice symmetry. On the other hand, the luminescence of Y2O3:Eu phosphors is increased by a kind of charge compensation caused by Li doping.