Influence on the luminescence properties of the lattice defects in Sr2MgSi2O7:Eu2+, M (M = Dy3+, La3+ or Na1+)

The luminescent properties of the Sr2MgSi2O7:Eu2+ phosphor have been investigated with different co-dopants. The co-dopants have no influence on the position of emission peak but the intensity of the emission and the afterglow. It associates with the decay of the afterglow. A cluster model involving the cation vacancies, the oxygen vacancies and the Dy3+ ions is proposed. These clusters provide the deep traps which trap the carriers more effectively. It leads to a greater intensity and longer duration of the afterglow. The La3+ ions do not enhance the TL intensity since the La2+ ions have a very high ionization and 4f → 5d energies. The experiment shows that the oxygen and the Sr2+ vacancies are not the crucial defects on the enhancement of the afterglow properties unless they aggregate with some suitable Re3+ ions.