The roles of Eu~(2+) and Dy~(3+) in the blue long-lasting phosphor Sr_2MgSi_2O_7: Eu~(2+), Dy~(3+)

摘要

The luminescent properties of the undoped, the Eu~(2+) or Dy~(3+) singly doped as well as Eu~(2+) and Dy~(3+) codoped Sr_2MgSi_2O_7, were investigated using synchrotron radiation and xenon or mercury lamp as excitation source. Under 172 nm excitation, besides the emission band peaked at 465 nm from Eu~(2+) in Sr_2MgSi_2O_7:Eu~(2+) , Dy~(3+), there are evident emission lines at 487 and 575 nm from intraconfigurational 4f transitions of Dy~(3+). After the UV excitation, the peak temperatures of thermoluminescence curves were at ～ 65℃ for Sr_2MgSi_2O_7:Eu~(2+) and ～ 120℃ for Sr_2MgSi_2O_7: Dy~(3+). Afterglow emission spectra peaking at 465 nm were increased with rising temperature from 180K to room temperature. The results show that the role of Eu~(2+) in Sr_2MgSi_2O_7:Eu~(2+), Dy~(3+) is not only the luminescence center, but also a trap center. On the contrary, the role of Dy~(3+) ions can be not only as a trap center, but also as a luminescence center.