Green-emitting Zn2SiO4:Mn phosphor particles having a spherical shape, high brightness, and short decay time were prepared by large-scale spray pyrolysis. The morphological control was attempted by using artificial colloidal solution obtained by adding the fumed silica particles to the aqueous solution. The particles prepared from the colloidal solution had a spherical and filled morphology even after post-treatment. To reduce the decay time of Zn2SiO4:Mn particles prepared by spray pyrolysis, barium was introduced as a codoping material. The effects of barium codopant concentration on the crystal structure, morphology, and luminescence properties such as luminescence intensity and decay time of Zn2SiO4:Mn particles were investigated. Zn2SiO4:Mn phosphor particles containing 0.1 mol % of barium codopant had a higher photoluminescence (PL) intensity and shorter decay time than the nonco-doped ones. The influence of post-treatment temperature on the decay time and PL intensities of Zn2SiO4:Mn particles was also investigated. The particles post-treated at 1145degreesC had the maximum PL intensity, which was 107% of that of the commercial product. Although the decay time of the optimized particles was similar to that of the commercial product (5.5 ms), that of prepared particles tended to be short with increasing post- treatment temperature. (Minimum decay time obtained was 4.5 ms.)