Luminescence intensity enhancement of Eu²⁺ and Eu³⁺ by Tb³⁺ in LiLa₉(SiO₄)₆O₂

Novel yellow-emitting phosphors LiLa₉(SiO₄)₆O₂: 0.05Eu, x Tb ( x   =  0, 0.01, 0.03, 0.02, 0.04, 0.06, 0.08, 0.10) were prepared by a solid-state reaction in a CO-reducing atmosphere. The excitation and emission spectra, and the fluorescence decays were measured and discussed in detail. The fluorescence spectra results of sample LiLa₉(SiO₄)₆O₂: 0.05Eu reveal that still a small amount of Eu³⁺ ions are detected in the LiLa₉(SiO₄)₆O₂ host. The introduction of Tb³⁺ ions can enhance the emission intensity of LiLa₉(SiO₄)₆O₂: 0.05Eu under near-ultraviolet light excitation but they do not vary the emission color much. The results indicate that the yellow-emitting phosphors LiLa₉(SiO₄)₆O₂: Eu, Tb can be considered as potential phosphor-converted materials for n-UV white light-emitting diodes. (paper)