A new synthetic method to prepare spherical phosphors for emissive screen applications

The new method for preparing spherical phosphors, which is based on aerosol pyrolysis, is described. Europium-doped yttrium oxide (Y2O3:Eu) phosphors are taken as an illustration. The resultant powder phosphors showed perfect spherical shape of 1 mu m av diam. A postannealing treatment of Y3O3:Eu powder phosphors was observed not to change their spherical shape and to be well crystallized. Measurements of cathodoluminescence showed that the yttrium oxide phosphors were similar to 130 % as bright as commercial products at low-voltage excitation. The improvements in brightness are presumably ascribed to the uniform distribution of activators in host lattice and no surface damage during the preparation process. By considering the fact that the spherical shape of phosphors results in the great enhancement of screen performance, this method may be a promising technique for emissive flat-panel display applications.