A Eu-doped BaAl2S4 phosphor was synthesized by a liquid-phase reaction using BaS, EuS, Al, and S, where Al acts as a liquid source during the reaction, instead of Al2S3. The synthetic temperature of the cubic BaAl2S4 phase could be reduced to as low as 660 C, considerably lower than that required for a phosphor synthesized via a solid-state reaction using BaS, EuS, and Al2S3. The cubic BaAl2S4:Eu phosphor synthesized using the liquid phase showed larger grains and higher crystallinity. The photoluminescence of the cubic BaAl2S4: Eu phosphor showed a blue emission centered at 470 nm with a CIE color coordinate at x = 0.12, y = 0.11. In addition to well-defined blue color, the PL intensity was doubled relative to the solid-state reaction case. (c) 2007 The Electrochemical Society.