Long persistent and photo-stimulated luminescence properties of β-Sr2SiO4:Eu2+, La3+ phosphors

A series of β-Sr2SiO4: Eu2+, La3+ phosphors have been synthesized via high temperature solid state reaction. Photoluminescence (PL), long persistent luminescence (LPL), and the photo-stimulated luminescence (PSL) suggest that Eu2+ ions occupy Sr(1) and Sr(2) sites. Significant enhancement of PL, LPL and PSL has been observed by co-doping La3+ in β-Sr2SiO4: Eu2+, La3+. Meanwhile, the introduction of La3+ ions increases significantly the intensities of the TL bands (T1 and T3 regions), and promotes the formation of a large number of traps in LPL and PSL. In addition, the observation of the PSPL(photo-stimulated long persistent luminescence) phenomenon demonstrates the occurrence of electrons which are retrapped by the shallow traps in the LPL process.