Gd₂O₃:Eu phosphor particles with sphericity, submicron size and non-aggregation characteristics

Gd₂O₃:Eu phosphor particles with red emission were directly prepared by a continuous spray pyrolysis process. Photoluminescence, morphology and crystallinity of the as-prepared and annealed particles were investigated. The particles prepared at 800 °C have sharp peaks of cubic phase Gd₂O₃, and the crystallinity of the cubic phase increased with increasing reactor temperature up to 1400 °C. The mean size of the particles increased from 0.35 to 1.2 μm when the solution concentration was increased from 0.02 to 1 M. The Gd₂O₃:Eu particles absorbed excitation energy in the range from 220 nm to 300 nm, and the maximum excitation wavelength was near 255 nm. The optimum brightness was obtained at a doping concentration of 10 at.%. The main emission peak was 612 nm, resulting in a red emission. The red light was obtained at 600 °C when the prepared particles were excited by UV light. The maximum PL intensity was obtained at 1400 °C, and the pattern of the PL spectra of the particles was changed at 1600 °C. The PL intensity of the as-prepared particles at 1400 °C was increased by a factor of 1.1 in comparison with annealed particles.