Samples of (Sr1.9-xBax)SiO4:Eu-0.1 were synthesized by a solid-state reaction. The maximum emission intensity under 460 nm excitation was obtained at a Ba content, x, of 1.6. All Sr1.9-xBaxSiO4:Eu-0.1 samples except for Ba1.9SiO4:Eu-0.1 exhibited a temperature-driven blue-shift of the emission band. The thermostability of emission in (Sr1.9-xBax)SiO4:Eu-0.1 depended strongly on the Ba/Sr ratio. The thermal quenching temperature reached its maximum at a Ba concentration x of 1.2-1.6 and was much lower for Ba1.9SiO4:Eu-0.1(2+). (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3625282] All rights reserved.