Tunable color emission and afterglow in CaGa2S4:: Eu2+, Ho3+ phosphor

The tunable color emission and persistent luminescence lifetime in phosphor CaGa2S4: Eu2+, Ho3+ were achieved through the introduction of alkaline earth elements Mg, Sr and Ba, in which the Ca was partially replaced. The duration of the persistent luminescence of the material CaGa2S4: Eu2+, Ho3+ was remarkably shortened as Al was introduced, substituting for Ga. The luminescent properties were investigated via thermo-luminescence (TL) glow curves, phosphorescence spectra and decay time curves. These results show that vast changes in trap levels and charge density takes place with introduction of other alkaline earth elements or Al. Trap depths and the trap density were also evaluated by simple methodologies. (c) 2007 Elsevier Ltd. All rights reserved.