Effects of BaF₂ flux on the properties of yellow-light-emitting terbium aluminum garnet phosphor powders prepared by spray pyrolysis

Spherical-like Tb₃Al₅O₁₂:Ce (TAG:Ce) phosphor powders with good photoluminescence intensities were prepared by spray pyrolysis from a spray solution containing BaF₂ flux. The phosphor powders prepared from the spray solution without the BaF₂ flux had irregular morphologies and aggregated structure. On the other hand, the phosphor powders obtained from the spray solution containing a high amount of BaF₂ flux were spherical-like shapes, narrow size distributions and non-aggregation. All the powders comprised single-phase body-centered cubic Tb₃Al₅O₁₂ (TAG), irrespective of the addition amount of the BaF₂ flux. The maximum photoluminescence intensity of the TAG:Ce phosphor powders obtained from spray solutions containing BaF₂ was 140% that of the phosphor powders obtained from the spray solution without the flux material. The mean size of the TAG:Ce phosphor powders prepared from the spray solution containing 9 wt.% BaF₂ with respect to the phosphor was 1.02 μm after post-treatment at 1450 °C.