Sr3Al2O5Cl2:Ce3+,Eu2+: A potential tunable yellow-to-white-emitting phosphor for ultraviolet light emitting diodes

The Sr3Al2O5Cl2:Ce3+,Eu2+ phosphors were prepared by solid state reaction. The obtained phosphors exhibit a strong absorption in the UV-visible region and have two intense emission bands at 444 and 609 nm. The energy transfer from the Ce3+ to Eu2+ ions was observed, and the critical distance has been estimated to be about 24.5 A by spectral overlap method. Furthermore, the developed phosphors can generate lights from yellow-to-white region under the excitation of UV radiation by appropriately tuning the activator content, indicating that they have potential applications as an UV-convertible phosphor for white light emitting diodes.