One red-emitting (Ca0.54Sr0.22Eu0.08La0.08) (Mo-0.4 W-0.6) O-4 phosphor was synthesized by the sol-gel method and the effect of La3+ ions on its emission property was investigated. Through luminescent spectra, XRD and SEM analyzing, the energy transfer schematic mechanism under NUV excitation was depicted and, according to Judd-Ofelt theory, the quantum efficiency and Omega(2,4) were calculated for energy transfer from host to Eu3+ ions in the (Ca0.54Sr0.34Eu0.08) (Mo-0.4 W-0.6) O-4 phosphor with La3+ ions doping or without. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3619774] All rights reserved.