Photoluminescence properties of Eu2+ doped Ba2ZnS3 phosphor for white light emitting diodes

The synthesis and photoluminescence properties of novel Eu2+ doped Ba2ZnS3 phosphors for white light emitting diodes (LEDs) are reported. Diffuse reflection spectra of Ba2ZnS3 host and synthesized phosphors have been measured. The excitation spectra of synthesized phosphors consist of three broad bands between 250 nm and 550 nm and are consistent with the diffuse reflectance spectra. The emission spectra show the characteristic 4f65d1 → 4f7 transition of Eu2+ ion and there exists efficient energy transfer from host to Eu2+ ions when excited by 350-nm light. The dependence of emission spectra on temperature is also measured; the possible reasons applied to explain the experimental results are also discussed. The fluorescence lifetime of Eu2+ in Ba1.995ZnS3:0.005Eu2+ is measured and the values are 1.49 and 23.4 μs.