We obtained a high-luminance Y2O3:Eu3+ red phosphor by spray pyrolysis without postheating treatment using a high-temperature furnace with a long residence time and the addition of alkali metal salts to the precursor solution. The luminance under UV and vacuum UV radiation was about 100 and 90% that of the conventional phosphor made by solid-state reaction. The phosphor with the highest luminance was synthesized from a precursor solution that contained a lithium salt at 1.6 times the total of the yttrium and europium molar quantity. Optimum pyrolysis conditions were 1600degreesC temperature and 12 s residence time. The median particle diameter of the phosphor was 1.0 mum, which is much smaller and less agglomerated than the commercial phosphor made by solid-state reaction, whose median diameter was 3.5 mum. Compared with the phosphor having 1.5 mum median particle diameter by the solid-state reaction, the luminance of the phosphor in this study was 125%. An X-ray diffraction study indicated that the highest luminance phosphor obtained by the addition of a lithium salt had little strain in the crystal and that crystal growth was promoted by the additive. (C) 2004 The Electrochemical Society.