Luminescence properties of (Ca1−xSrx)Se:Eu2+ phosphors for white LEDs application

Abstract Novel phosphors of Eu 2+ -doped (Ca 1− x Sr x )Se for the application of white light emitting diodes (LEDs) were prepared by conventional solid-state reaction. Diffuse reflection spectra of CaSe, SrSe, CaSe:Eu 2+ and SrSe:Eu 2+ were measured. The excitation spectra consisted of two broad bands and were consistent with the diffuse reflectance spectra. The emission band is due to the 4f 6 5d 1 →4f 7 transition of the Eu 2+ ion. With an increase in x , the emission band shifted to shorter wavelength and the reason was discussed. The fluorescence lifetimes of Eu 2+ in (Ca 1− x Sr x )Se:0.04Eu 2+ were also measured and the values were reasonable for the allowed transition 4f 6 5d 1 →4f 7 in Eu 2+ .