Synthesis of agglomerate-free YAG: Ce3+ phosphors by co-precipitation and low temperature spray pyrolysis

Y_3-xCe_xAl₅O₁₂ (YAG: Ce³⁺) phosphor particles were prepared by a new method called co-precipitation and low temperature spray pyrolysis (CP-LTSP) with oxalic acid and ammonia as precipitant. It corresponds to the first-step chemical liquid reaction, the second step dehydration and partial decomposition of precipitation droplets at 250°C and then heating at 1100°C or above. Spherical as-prepared particles and agglomerate-free YAG: Ce³⁺ phosphor particles were obtained respectively. Pure YAG phase could be formed after LTSP at 250°C and then annealing at 1100°C for 4 h. The emission spectra and XRD patterns of YAG: Ce³⁺ phosphor particles indicated that the optimum doping concentration of Ce³⁺ was 0.06. The emission intensity increased with the increase of annealing temperature. As a result, the YAG: Ce³⁺ phosphor particles without optimization annealed at 1550°C for 4 h had the similar emission intensity (96%) of the commercial phosphor by the solid-state method.