SrAl2O4 phosphor excited with fluorescent light or sunlight, has been recen
tly reported to be a long-lasting afterglow (AG) phenomenon. However, the A
G mechanism has not been clarified yet, In this study, the long-lasting AG
mechanism of SrAl2O4 phosphors doped with Eu and/or Dy, was investigated on
the basis of AG, photoluminescence (PL), and thermoluminescence (TL) measu
rements after UV or X-ray irradiation. A hole trap is presumed to be ascrib
ed to Sr defects, which increases and is stabilized by a charge compensatio
n behavior upon doping Dy ion. An electron trap probably originates from ox
ygen defects, as produced by firing in a reductive atmosphere. Furthermore,
the role of dopants (Eu, Dy ion) on SrAl2O4 phosphor co-doped with Eu and
Dy ions, was studied by comparing the luminescence (AG and PL) phenomena wi
th the distribution of dopant in SrAl2O4 matrix. Eu ion contributed closely
to both the AG and PL behaviors, while the Dy ion contributes only to the
AG phenomenon.