About red afterglow in Pr3+ doped titanate perovskites

The red phosphor CaTiO3 : Pr3+ is known to show a persistent luminescence in the red spectral region upon irradiation in the UV. Although a number of studies have been dedicated to the enhancement of the afterglow efficiency in this perovskite by varying the preparation method, the chemical composition or the particle size, no clear explanation of the mechanisms involved in the afterglow process has been given yet. The purpose of this paper is to start investigating this aspect on the basis of a recently developed model and by using the luminescence and afterglow properties of the solid solution (Ca, Sr)TiO3 : Pr3+ as experimental support.