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

Abstract

In this study, the regulation of Al³⁺/Ga³⁺ on Sr₂(Ga,Al)₂SiO₇: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 Sr₂(Ga,Al)₂SiO₇: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 Sr₂(Ga,Al)₂SiO₇. Finally, with the stimulation of a 1060 nm laser, the optimized Sr₂(Ga,Al)₂SiO₇:Ce³⁺ phosphors show strong persistent luminescence of Ce³⁺, suggesting the potential for application in optical storage.