$(Y_xGd_{1-x})_2O_3:Eu$ (0≤x≤1) phosphor particles with dense and spherical morphology were prepared by flame spray pyrolysis, because high temperature diffusion flame caused the melting of particles. But The high temperature of diffusion flame produced the particles with monoclinic phase. For the phase transformation to cubic phase, proper post-treatment was found to be required. After post-treatment, the particles were transformed to cubic phase and maintained spherical morphology. The Y/Gd ratio and the addition of flux influenced post-treatment conditions and morphology. The particles with the low Y/Gd ratio required high post-treatment temperature, and the addition of flux lowered the post-treatment temperature regardless of Y/Gd ratio. The particles prepared with flux were somewhat aggregated, and the aggregation became more severe when the Y/Gd ratio decreased. The particles prepared by flame spray pyrolysis had high photoluminescence intensity comparable with commercial product.
