Photoluminescence and afterglow behavior of Ce3+ activated Li2Sr0.9Mg0.1SiO4 phosphor

Abstract

A blue emitting phosphor Li2Sr0.9Mg0.1SiO4:Ce3+, with long persistence, was synthesized via a high-temperature solid phase method. According to the X-ray diffraction analysis result, the introduction of Mg2+ and Ce3+ ions has no influence on the structure of the host material. Typical 5d-2F5/2 and 5d-2F7/2 transitions of Ce3+ ions were detected by PL spectra, which corresponded to the CIE chromaticity coordinates of x = 0.1584, y = 0.0338. An optimal doping concentration of Ce3+ was determined as of 0.4 at%. Furthermore, the Li2Sr0.9Mg0.1SiO4:Ce3+ phosphor showed a typical triple-exponential afterglow behavior when the UV source was switched off. The highest lifetime of the electrons within the material reached a value of 73.9 s. Thermal stimulated luminescence study indicated that the afterglow of Li2Sr0.9Mg0.1SiO4:Ce3+ was due to the recombination of the electrons with holes released from the traps generated by the doping of Ce3+ ions in the Li2Sr0.9Mg0.1SiO4 host. The afterglow mechanism of Li2Sr0.9Mg0.1SiO4:Ce3+ is illustrated and discussed in detail on the basis of the experimental results.