The sintering flux of BaF2, H3BO3, and Li2CO3 were introduced into the blue-green emitting Ba9Lu1.9Ce0.1Si6O24 (BLS:10%Ce3+) phosphor. By adding few amount of flux, the crystallization temperature lowers from 1400 to 1200 degrees C and the crystal structure has no change. H3BO3 does not change the luminescence properties of BLS:10%Ce3+. BaF2 blue shifts the excitation spectrum of BLS:10% Ce3+. Li2CO3 blues shift the excitation and emission spectra of BLS:10%Ce3+. In addition to the effect of sintering assistant, Li2CO3 also has a role of a charge compensator to balance the charge difference between Ce3+ and Ba2+. Thus, Ce3+ prefers to occupy the Ba2+ site rather than the Lu3+ site, which strongly blue shift the Ce3+ emission from green color to blue color. (C) 2017 Elsevier Ltd. All rights reserved.