Influence of co-doping different rare earth ions on CaGa2S4: Eu2+, RE3+(RE=Ln) phosphors

Abstract Photoluminescent phosphors CaGa 2 S 4 : Eu 2+ , RE 3+ (RE 3+ including all rare earth ions except for Sc 3+ , Pm 3+ , Eu 3+ and Lu 3+ ) were prepared by sintering at high temperature in a reductive atmosphere, and their luminescent properties were studied intensively. The influences of co-doping rare earth ions on their luminescent properties were also investigated. No remarkable differences were found from excitation spectra of co-doped phosphors CaGa 2 S 4 : Eu 2+ , RE 3+ in contrast with that of phosphor CaGa 2 S 4 : Eu 2+ , but there were a few differences in emission spectra of Ce 3+ , Pr 3+ or Ho 3+ co-doped phosphors. Phosphors CaGa 2 S 4 : Eu 2+ , RE 3+ (RE=Ce, Pr, Gd, Tb, Ho and Y) had persistent afterglow, and very short afterglow was shown for Nd 3+ or Er 3+ co-doped phosphors, but no long afterglow appeared when auxiliary activator was La 3+ , Sm 3+ , Dy 3+ , Tm 3+ or Yb 3+ . Among the phosphors with long-lasting phosphorescence, in our experiments, CaGa 2 S 4 : Eu 2+ , Ho 3+ had the longest and the highest brightness long yellow afterglow. Thermo-luminescence of all co-doped phosphors was measured to find the answer of different influences from different rare earth auxiliary activators.