Luminescence Properties of Sr 2 SnO 4 :Sm 3+ Afterglow Phosphor

A new long-lasting phosphorescence (LLP) phosphor, Sr 2 SnO 4 :Sm 3+ , which emits reddish-orange LLP upon UV-excitation, is prepared by a conventional high-temperature solid-state method. After irradiation under 247-nm UV light, Sr 2 SnO 4 :Sm 3+ emits an intense reddish-orange emission afterglow from the 4 G 5/2 to 6 H J (J = 5/2, 7/2, 9/2) transitions. The afterglow decay curve of the Sm 3+ -doped Sr 2 SnO 4 phosphor contains a fast decay component and another slow decay one. Due to the presence of the slow decay component, the afterglow can be seen with the naked eye in the dark clearly for more than 1 h after removal of the excitation source.