Study of the cation distributions in Eu doped Sr2Y8(SiO4)6O2 by X-ray diffraction and photoluminescent spectra

The crystal structure and photoluminescent properties of europium doped silicate Sr2Y8(SiO4)6O2:Eu3+ are reported. The Sr2Y8−xEux(SiO4)6O2 compounds have typical apatite crystal structures with the P63/m space group. The distributions of Eu3+ between the two crystallographic sites 4f and 6h in the apatite structure are investigated by the powder X-ray diffraction and Rietveld refinement. Results show that Eu3+ ions only occupy the 4f sites when the Eu doping concentration is low (x=0–0.5 in Sr2Y8−xEux(SiO4)6O2). However, in higher concentrations, Eu3+ ions begin to enter the 6h sites as well. The distributions of the Eu3+ are also reflected in photoluminescent spectra. The CIE coordinates for Sr2Y6Eu2(SiO4)6O2 are (0.63, 0.37), which is close to the pure red color.

Graphical abstractThe crystal structures of Eu doped Sr2Y8(SiO4)6O2 especially the distributions of Eu3+ cations between 4f and 6h sites were studied by X-ray diffraction, Rietveld refinement and photoluminescent spectra.Figure optionsDownload full-size imageDownload as PowerPoint slide