Luminescence spectra and site-occupation of Eu3+ centres in lithium antimonate LiSbO3 lattice

Abstract

It is a challenge to accurately determine the exact location of the rare earth ion (RE) in the lattice when there are significant differences in radius, electronegativity and valence between the lattice cation and the corresponding RE activator in a host material. This study presents the findings on the luminescence and site occupancy of Eu3+ emission centers in the lithium antimonate LiSbO3 lattice. The phase-formation, structures, elemental composition, band transition characteristics, luminescence properties, and lifetimes of the Eu3+-doped phosphors were investigated. Eu3+-doped LiSbO3 exhibits a typical 5D0→7F2 red luminescence transition at 613 nm. Site-selective excitation, luminescence, and decay properties at the 7F0→5D0 transition wavelength were measured using a tunable pulsed narrow-band dye laser. Two Eu3+ luminescence centers in LiSbO3 were identified across the temperature range from 10 K to 300 K. The doping of RE(Eu3+) in LiSbO3 consistently occupies two crystallographic positions of Li+ and Sb5+. Furthermore, the probability of RE(Eu3+) ions preferentially occupying the Li+ (M) sites is notably high. The decay curves and luminescence lifetimes of the two Eu3+ centers were determined. Drawing from the experimental data, we discuss the potential defects induced by Eu3+ doping in LiSbO3 and the mechanism of charge compensation. These results could be instrumental in the advancement of new RE-activated luminescent materials or serve as a reference for investigating the specific positioning of RE ions within a phosphor lattice.