Photoluminescence properties of rare-earth activated BaSi7N10

The photoluminescence properties of Eu2+-, Ce3+- and Tb3+-activated BaSi7N10 have been studied. The transitions of f ↔ d of the Eu2+ and Ce3+ ions occur at relatively high energies for nitrides which are principally attributed to weak bonding strength of Ba–N and small crystal field splitting of 5d excitation levels of Eu2+ and Ce3+ due to a large Ba crystallographic site in BaSi7N10. As a result, it was found that BaSi7N10:Eu2+ showed blue emission at about 475 nm originating from the 4f65d1 → 4f7 transition of Eu2+ upon UV excitation. While BaSi7N10:Ce3+, Li+ exhibited UV-blue emission with a maximum at about 400 nm caused by the 5d → 4f transition of Ce3+. In BaSi7N10:Tb3+, Li+, the luminescence spectrum of Tb3+ was dominated by green line emission arising from the 5D4 → 5FJ (J = 3, 4, 5, 6) transitions.