Photoluminescence properties and energy transfer in Ce~(3+)/Dy ~(3+) co-doped Sr_3MgSi_2O_8 phosphors for potential application in ultraviolet white light-emitting diodes

摘要

Sr_3MgSi_2O_8:Ce~(3+), Dy ~(3+) phosphors were prepared by a solid-state reaction technique and the photoluminescence properties were investigated. The emission spectra show not only a band due to Ce~(3+) ions (403 nm) but also as a band due to Dy~(3+) ions (480, 575 nm) (UV light excitation). The photoluminescence properties reveal that effective energy transfer occurs in Ce ~(3+)/Dy~(3+) co-doped Sr_3MgSi_2O _8 phosphors, and the co-doping of Ce~(3+) could enhance the emission intensity of Dy~(3+) to a certain extent by transferring its energy to Dy~(3+). The Ce~(3+)/Dy~(3+) energy transfer was investigated by emission/excitation spectra, and photoluminescence decay behaviors. In Sr_(2.94)MgSi_2O_8:0.01Ce ~(3+), 0.05Dy~(3+) phosphors, the fluorescence lifetime of Dy~(3+) (from 3.35 to 27.59 ns) is increased whereas that of Ce ~(3+) is greatly decreased (from 43.59 to 13.55 ns), and this provides indirect evidence of the Ce~(3+) to Dy~(3+) energy transfer. The varied emitted color of Sr_3MgSi_2O_8:Ce ~(3+), Dy~(3+) phosphors from blue to white were achieved by altering the concentration ratio of Ce~(3+) and Dy~(3+). These results indicate Sr_3MgSi_2O_8:Ce~(3+), Dy~(3+) may be as a candidate phosphor for white light-emitting diodes.