Design, synthesis and characterization of a novel orange-yellow long-lasting phosphor: Li2SrSiO4:Eu2 +, Dy3 +

• A significant enhancement of LLL property is achieved by doping Dy3 + ions.
• Afterglow of Li2Sr0.993SiO4:0.003Eu2 +, 0.004Dy3 + can persist over 15 h.
• Vo.. as electron traps is responsible for LLL of single/co-doped samples.

A novel orange-yellow long-lasting phosphor (LLP) Li2SrSiO4:Eu2 +, Dy3 + was developed. The incorporation of the orbitals of Dy3 + in the formation of the discrete level associated with oxygen vacancy (Vo..) causes a change in the number of traps, which largely extends the thermoluminescence characteristics and evidently improves the long persistent luminescence property of the phosphor. Both fluorescence and phosphorescence spectra of Li2SrSiO4:Eu2 +, Dy3 + reveal broad and intensive emission extending from 500 to 700 nm with a peak at about 567 nm, this indicates that photoluminescence(PL) and long-lasting luminescence (LLL) are from the same Eu2 + ions center. After the removal of UV light, the afterglow of the sample with the optimum doping concentration can persist over 15 h above the recognizable intensity level (≥ 0.32 mcd/m2).

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