Red phosphorescence in Sr4Al14O25: Cr3+,Eu2+,Dy3+ through persistent energy transfer

Cr 3 + , Eu2+, and Dy3+ codoped Sr4Al14O25 has been synthesized by solid-state reaction. Long persistent phosphorescence in red of Cr3+ and in blue of Eu2+ has been observed in this system with persistence times of over 2h for the red and 10h for the blue. Red phosphorescence is performed through persistent energy transfer from Eu2+ to Cr3+, converting the blue to the red. Concentration effect is analyzed based on energy transfer. The calculated results are in good agreement with the experimental data. The different decay patterns of the red and blue phosphorescence are measured and discussed.