Long-lasting phosphorescence study on Y 3Al 5O 12 doped with different concentrations of Ce 3+

Abstract

Long-lasting phosphorescence (LLP) was observed in Ce-doped Y 3Al 5O 12 phosphors synthesized in reducing atmosphere. The characteristic emission of the 2D- 2F 5/2 and 2D- 2F 7/2 transition of Ce 3+ in photoluminescence (PL) and LLP spectra was studied. It was interesting that the ratio between the peak areas of 2D- 2F 5/2 and 2D- 2F 7/2 transitions in the PL spectrum was different from the ratio of that in LLP emission spectrum. And the ratios had different change regularities with increased Ce 3+ concentration. The possible reason was attributed to the defect in the YAG host, which was affected by increasing the Ce 3+ concentration. There were indications that the defect in the Ce 3+-doped YAG samples was strongly associated with oxygen vacancy. And the defect levels were studied through thermoluminescence (TL) experiment. The results showed that the trap depth was between 0.6 and 0.65 eV, and the kinetic order of the LLP was 2.