Effects of Nd3+ co-doping on the long lasting phosphorescence and optically stimulated luminescence properties of green emitting NaBaScSi2O7:Eu2+ phosphor

• The optically stimulated luminescence property of NaBaScSi2O7:Eu2+ was studied.
• The introduction of Nd3+ ion enhances the LLP and OSL properties of NaBaScSi2O7:Eu2+.
• The persistent green emission can last for about five and a half hours.
• A possible mechanism for the optical phenomenon is proposed.

Green emitting NaBaScSi2O7:Eu2+/Eu2+, Nd3+ phosphors are prepared by a solid state reaction under a reductive atmosphere. The introduction of Nd3+ ion, which acts as trap center, largely extends the thermoluminescence characteristics and evidently enhances the long lasting phosphorescence and optically stimulated luminescence properties of the phosphors. The persistent green emission of the co-doped phosphor can last for about five and a half hours above recognizable intensity level (≥0.32 mcd/m2). According to the analysis of thermoluminescence characteristics, it is concluded that the shallow T1′ traps with a continuous trap depth distribution are exactly the traps that lead to the long lasting phosphorescence and other three kinds of deep traps, i.e., T2′, T3′ and T4′, corresponding to a separated trap depth distribution, should mainly contribute to the optically stimulated luminescence performance. Finally, a possible mechanism for the optical phenomenon is proposed.

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