Judd-Ofelt description of radiative properties of YNbO4 activated with different Eu3+ concentrations

Abstract

YNbO4:xEu3+ powders (0.1, 0.25, 0.5, 0.75, 1, 3, 5, 7.5, 10, 15, 20 mol %) were synthesized by a solid-state reaction, after homogenization in a vibrational mill. All the samples crystallize in a monoclinic Fergusonite-beta-(Y) structure (C2/c space group), with 45–65 nm crystallite sizes and show a strong orange/red luminescence with 5D0 excited state lifetimes of around 0.6 ms. Photoluminescence emission spectra showed no concentration quenching within the examined concentration range. Judd–Ofelt intensity parameters show a slight increase with rising concentration, up to Ω2 = 8.13∙10−20 cm2, Ω4 = 2.67∙10−20 cm2, and Ω6 is concentration invariant with the 0.35∙10−20 cm2 value. Emission lifetimes of the 5D0 state are almost constant with ∼0.6 ms, and a slight decrease is observed with the highest concentrations. The intrinsic quantum yield of all the samples is about 0.5.