Doping effect of Tb3+ ions on luminescence properties of Y3Al5O12:Cr3+ phosphor

Tb3+or/and Cr3+ doped or co-doped Y3Al5O12(YAG) garnets were prepared by a citric acid sol-gel method. Single-phase YAG, YAG:Tb3+,YAG:Cr3+and YAG:Cr3+,Tb3+powders were obtained already at 1000 °Cand were further annealed at 1600 °C to increase the crystallinity. All materials were characterized by X-ray diffraction (XRD), thermogravimetric (TG), photoluminescence (PL), reflection and photoluminescence decay measurements. Scanning electron microscopy (SEM) was used for morphology description. Luminescence measurements indicated that Tb3+ ions located at dodecahedral sites transfer absorbed energy to Cr3+ ions located at octahedral sites resulting quenched Tb3+ and strengthened Cr3+ emission in YAG:Cr3+, Tb3+ upon 273 nm excitation.