Enhanced thermal stability and afterglow performance in Sr2Ga2-xAlxSiO7:Ce3+ phosphors via band gap tailoring

In this study, the regulation of Al3+/Ga3+ on Sr-2(Ga,Al)(2)SiO7:Ce3+ phosphors is demonstrated to enhance the photoluminescence and persistent luminescence (PersL) performances of Ce3+. With the replacement of Al3+, the emission band of Ce3+ shifts to the longer wavelength side, thermal stability of Ce3+ emission becomes better, and Ce3+ persistent luminescence shows stronger intensity and longer lifetime. To get insight into the structure-luminescence relationship, the influences of Al3+/Ga3+ on the structure of Sr-2(Ga,Al)(2)SiO7:Ce3+, 4f-5d(i) (i = 1-5) transition energies of Ce3+ and trap distributions are discussed. With the construction of the vacuum referred binding energy scheme and analysis of a series of thermoluminescence (TL) spectra, the increase of band gap is found to tune the trap depths and change persistent luminescence performances of Ce3+ in Sr-2(Ga,Al)(2)SiO7. Finally, with the stimulation of a 1060 nm laser, the optimized Sr-2(Ga,Al)(2)SiO7:Ce3+ phosphors show strong persistent luminescence of Ce3+, suggesting the potential for application in optical storage.