Anew host material BaMg(1+x)SixAl10Oy has been prepared and studied for use with Eu2+ ions as a thin-film phosphor. Films were prepared by a spray pyrolysis method at ambient pressure. Magnesium hexafluorosilicate was used as the precursor for the silicon component. In comparison with BaMgAl10O17 (BAM), this host required a lower annealing temperature to convert Eu3+ to Eu2+. In the crystalline matrix, Eu2+ emitted a narrow line at 450 nm. In amorphous films, Eu2+ emitted two broad lines at 440 and 500 nm and several narrow red lines around 612 nm that made the luminescence look white. Deposition and post-deposition conditions were determined for maximum luminance. Heat treatment at 650 degreesC achieved essentially the same intensity of the blue-green luminescence as that of BAM films, which were annealed at 1000 degreesC.