Red luminescence and persistent luminescence of Sr3Al2O5Cl2:Eu2+,Dy3+

The luminescence and persistent luminescence properties of Sr3Al2O5Cl2:Eu2+ and Sr3Al2O5Cl2:Eu2+,Dy3+ phosphors have been investigated. Both materials show d-f emission of Eu2+ in the orange/red spectral region around 615 nm at room temperature. The temperature dependent emission spectra and decay curves of Eu2+ ions doped into Sr3Al2O5Cl2 are reported and discussed. Sr3Al2O5Cl2:Eu2+ shows considerable thermal quenching of its luminescence. It is also observed that the position of the emission band strongly depends on the temperature and shifts toward higher energy with increasing temperature, from 645 nm at 77 K to 594 nm at 500 K. Both, Sr3Al2O5Cl2:Eu2+ and Sr3Al2O5Cl2:Eu2+,Dy3+ show persistent luminescence. The persistent luminescence of Sr3Al2O5Cl2:Eu2+ is rather weak and lasts only for solely a few seconds, while the same material co-doped with Dy3+ shows longer and stronger afterglow.