Submicron-sited spherical yttrium oxide based phosphors prepared by supercritical CO2-assisted aerosolization and pyrolysis

The synthesis of Eu(III)- and Tb(III)-doped yttrium oxide phosphor powders by supercritical CO2-assisted aerosolization and pyrolysis (at 1010 degrees C) from aqueous solutions of Y(NO3)(3), Eu(NO3)(3), and Tb(NO3)(3) is presented. Dense, submicron aerosols are formed by contacting aqueous solutions of the precursor metal nitrates with supercritical CO2 at 1500 psi, and decompressing the mixture through a restrictor nozzle into a heated tube. X-ray diffraction data indicate that the powders are crystalline, and consist of a single phase. Scanning electron microscope shows that they are spherical in morphology and less than 1 mu m in size with average diameters of similar to 0.2 mu m. The cathodoluminescence intensity of the Y1.91Eu0.09O3 powders, annealed at 1200 degrees C for 1 h, is more than twice greater than that of the industrial standard (P56, 3-10 mu m in diameter) phosphor. The phosphors synthesized by this method are promising candidates for use in high-resolution low-voltage flat panel displays. (C) 1997 American Institute of Physics.