Luminescence properties of (Ca_(1-x)Sr_x)Se:Eu~(2+) phosphors for white LEDs application

摘要

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~65d~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~65d~1->4f~7 in Eu~(2+).