Effect of Eu3+, Bi3+, and Li+ doping on luminescent property of GdNbO4

We investigated the emission properties of Eu3+-doped GdNbO4-based oxide phosphors, aiming at improving the Eu3+ emission by codoping of Bi3+ and Li+. Eu3+ singly doped, Eu3+ and Bi3+ doubly doped, and Eu3+, Bi3+, and Li+ triply doped GdNbO4 were prepared using a high-temperature solid-state reaction method. The red-orange emissions from Eu3+ in the singly doped samples are significantly improved by the codoping of Bi3+, mainly due to the energy transfer from Bi3+ to Eu3+. The additional codoping of Li+ is found to increase the Eu3+ emission significantly. This improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity. A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio esti-mated from the photoluminescence spectra show that the local lattice environment around Eu3+ in GdNbO4 does not change significantly with the codoping of Bi3+ and Li+. Our results indicate that Li+ doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO4 phosphors.(c) 2022 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.