Y2O2S co-doped with Bi3+, Eu3+ phosphors were prepared and their luminescence properties under vacuum ultraviolet (VUV) excitation were investigated. Much stronger red emission for Y2O2S:Eu3+,Bi3+ were observed under 147 nm excitation than that for Y2O2S:Eu3+ Investigation on photoluminescence and Calculation of electronic structure of Y2O2S:Eu3+,Bi3+ revealed that the Bi3+ acts as a medium in energy transfer process and the great VUV luminescence enhancement of Y2O2S:Eu3+ by doping Bi3+ is due to effective energy transfer process: charge transfer (CT) transition of Y3+-O2- -> Bi3+ -> Eu3+. The Y2O2S:Eu3+,Bi3+ showed excellent optical properties when compared with the commercial (Y,Gd)BO3:Eu3+. Thus. the Y2O2S:Eu3+,Bi3+ would be a promising VUV-excited red phosphor. (C) 2008 Elsevier Ltd. All rights reserved.