The persistent energy transfer of Eu and Mn and the thermoluminescence properties of long-lasting phosphor Sr3MgSi2O8:Eu, Mn, Dy

Eu²⁺, Mn²⁺ and Dy³⁺ co-doped long-lasting phosphors Sr₃MgSi₂O₈ were prepared by a solid-state reaction under a reductive atmosphere. Fluorescence spectra demonstrated that the weak red emission resulting from the forbidden transition of Mn²⁺ could be enhanced by the energy transfer from Eu²⁺ to Mn²⁺. The energy transfer between Eu²⁺ and Mn²⁺ was systematically investigated. The phosphorescence spectra revealed that Eu²⁺ could persistently transfer its energy to Mn²⁺ after removing the excitation source. The duration of Mn²⁺ can prolong to more than 2 h. The thermoluminescence spectra were used to characterize the ability of the trap to trapping the carriers. By the analysis of the ionization potentials, the roles of Mn²⁺ and Dy³⁺ in the afterglow process were discussed. A possible afterglow mechanism was presented and discussed.