Photoluminescence properties of solid solutions of YNbO₄, GdNbO₄ and LuNbO₄

Abstract

The photoluminescence properties of solid solutions of YNbO₄, GdNbO₄, and LuNbO₄ were investigated to determine the rare earth composition that maximizes the intrinsic luminescence intensity. All samples exhibited a monoclinic β-fergusonite-type structure without impurity phases. The intrinsic luminescence intensity followed the order of GdNbO₄, YNbO₄ and LuNbO₄, with GdNbO₄ showing significantly low intensity due to concentration quenching and self-absorption by Gd³⁺. Among the solid solutions, (Y,Lu)NbO₄ showed higher luminescence intensity than LuNbO₄, with Y_0.75Lu_0.25NbO₄ exhibiting the highest intensity, approximately 42 % higher than LuNbO₄. Fluorescence lifetime measurements of (Y,Lu)NbO₄ showed single-component decay curves with lifetimes ranging from 3.3 to 4.3 µs, with no significant differences or correlation with luminescence intensity.