Mechanism of long phosphorescence of SrAl2O4:Eu2+, Dy3+ and CaAl2O4:Eu2+, Nd3+
Abstract
The intense and long-lasting phosphorescence of SrAl2O4:Eu2+, Dy3+ and CaAl2O4:Eu2+, Nd3+ is produced by holes thermally released from the trap levels formed by Dy3+ or Nd3+, which has the optimum trap depth. Photoconductivity measurements show that the holes are supplied from the Eu2+ centers during the 4f → 5d excitation with a low activation energy.
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