Photoluminescence and afterglow behavior of Tb3+ activated Li2SrSiO4 phosphor

A green emitting long afterglow phosphor Li2SrSiO4:Tb3+ was obtained via a conventional high temperature solid-state reaction in air atmosphere. X-ray diffraction (XRD), photoluminescence spectroscope (PLS), long afterglow spectroscope (LAS) and thermal luminescence spectroscope (TLS) were performed to characterize the physical properties of the phosphors. Typical 5D4-7Fj transitions of Tb3+ ions were detected by PL spectra, corresponding to CIE chromaticity coordinates of x=0.3161, y=0.5472. An optimal concentration of Tb3+ in the substrate was determined to be 1%. The Li2SrSiO4:Tb3+ phosphors showed a typical afterglow behavior when the UV source was switched off. A typical triple exponential decay behavior was confirmed after fitting the experimental data. Thermal simulated luminescence study further indicated that the afterglow behavior of Li2SrSiO4:Tb3+ phosphors was generated by the recombination of electrons with the holes resulted from the doping of rare-earth ions (Tb3+) in Li2SrSiO4 host. The long afterglow luminescence mechanism of Li2SrSiO4:Tb3+ is illustrated and discussed in details on the basis of the experimental results.