Luminescence properties of Ce 3+ in orthosilicate oxyapatite NaY 9 (SiO 4 ) 6 O 2 .

Ce3+ -doped orthosilicate oxyapatite NaY9 (SiO4 )6 O2 phosphors NaY9-x (SiO4 )6 O2 :xCe3+ were prepared by a conventional high-temperature solid-state reaction method, and their spectroscopic characteristics were systematically investigated. The occupancies of Ce3+ ions at two different sites (Wyckoff 6 h and 4f sites) in NaY9 (SiO4 )6 O2 were determined. The influence of doping concentration on the emission intensity of Ce3+ was investigated and the critical distance Rc was estimated in terms of the concentration quenching data.