Energy-Transfer-Induced Tunable Luminescence in Mg 2 Al 4 Si 5 O 12 :Ce 3+ /Dy 3+ Phosphors

Ce3+- or/and Dy3+-doped Mg2Al4Si5O18 phosphors have been fabricated via a sintering process at 1400°C for 5 h and their crystallinity and luminescence characteristics investigated. x-Ray powder diffraction analysis demonstrated that Ce3+/Dy3+ ions entered the Mg2Al4Si5O18 host and formed a solid solution. When excited at 345 nm, Ce3+-doped Mg2Al4Si5O18 phosphor emitted light in the blue region while Dy3+-doped Mg2Al4Si5O18 phosphor emitted light in the yellow region. When excited at 345 nm, emission bands located in both the blue and yellow regions were observed for the Ce3+/Dy3+-codoped Mg2Al4Si5O18 phosphor. Because of Ce3+ → Dy3+ energy transfers, the Ce3+/Dy3+-codoped Mg2Al4Si5O18 phosphor showed tunable luminescence, changing from the blue to yellow–green region through the white region with increasing Dy3+ concentration in the Ce3+/Dy3+-codoped Mg2Al4Si5O18 phosphor. The decay characteristics of the Ce3+ emission in the Ce3+/Dy3+-codoped Mg2Al4Si5O18 phosphors were also investigated. With increasing Dy3+ concentration, the lifetime of the Ce3+ emission decreased continuously, further confirming the occurrence of Ce3+ → Dy3+ energy transfer.