Luminescence properties of Eu 2+ and Eu 3+ doped calcium-deficient hydroxyapatite prepared in air

Abstract

Eu-doped calcium-deficient hydroxyapatite Ca 8.95Eu 0.05HPO 4(PO 4) 5OH (designated CDHA:Eu) was prepared via the coprecipitation method and calcined in air. Phase purity, crystal structure and morphology of the CDHA:Eu were characterized using X-ray diffraction spectrometer and scanning electron microscopy. The photoluminescence excitation and emission spectra of Eu 2+ and Eu 3+ ions were measured using luminescence spectrometer. The emission spectra showed a broad emission band centered at 450 nm corresponded to the typical 4f 65d 1 → 4f 7 transition of Eu 2+ ions, and sharp peaks corresponded to the 5D 0 → 7F J ( J = 0, 1, 2, 3, 4) transitions of Eu 3+ ions. This research was focused on the site-distribution of Eu 3+ ions. The Eu 3+ in different sites had different spectroscopic features and the charge compensation mechanisms were also discussed.