A Red Long-Lasting Phosphorescence Material Gd9.33(SiO4)6O2:Sm3+ and Effect of Oxygen Vacancies on Its Performance

A novel red long-lasting phosphorescence material Gd-9.33(SiO4)(6)O-2:Sm3+ was reported in this paper. There are two kinds of Gd sites occupied by Sm3+ ions in this host matrix, Gd1 (CN = 9) and Gd2 (CN = 7). The Gd2 site is surrounded by six oxygen atoms bonded to silicon and one free oxygen atom which may be missed easily and then become an oxygen vacancy. A significant sequential enhancement on the afterglow performance of the air-sintered, the vacuum-sintered and the reduction-sintered samples was observed. This improvement could be attributed to the increase of oxygen vacancies acting as sensitizer and electron traps for afterglow, which was investigated with thermoluminescence. It is established that, the traps arising from oxygen defects (oxygen vacancies mostly) are responsible for the afterglow phenomenon of the Gd-9.33(SiO4)(6)O-2:Sm3+ phosphor. (C) 2013 The Electrochemical Society. All rights reserved.