When the bright green-emitting SrAl 2 O 4: Eu, Dy persistent phosphor was described in the
literature in 1996, this presented a real breakthrough in performance, both in terms of initial
brightness and afterglow duration. Since then, many new persistent phosphors, with
emission spanning from the ultraviolet to the near infrared, have been developed. Very few
materials, however, reach a similar afterglow time and intensity as SrAl 2 O 4: Eu, Dy, which
is still considered the benchmark phosphor. The present paper discusses the reasons for …