Influence of Bi2O3 co-doping on Cr-doped ZnGa2O4 red persistent phosphors synthesized by a liquid phase precursor process

Abstract The long persistence luminescent property of Cr-doped ZnG2O4 phosphor in the deep red/near-infrared region has been of great interest for the purpose of in vivo bioimaging application. Improving the optical property and afterglow lifetime of this material remain challenging. The microcrystalline cellulose assisted liquid phase precursor process was developed for the synthesis of high-quality ZnGa2O4 phosphors, which process enables uniform distribution of the dopant and co-dopant. In this paper, the co-doping of Bi enhanced the photoluminescence intensity by about 2.5 times, while significantly improving the long afterglow property. Investigation of the influence of the Bi addition indicated that the co-doping Bi not only serves to purify Cr ions in ZnGa2O4, but also brings about the growth of particles and changes in morphology through the role of flux.