Crystal structure and photoluminescence of (Ba1−x−ySryEux)9Sc2Si6O24

Divalent europium-doped alkaline earth metal silicate phosphors, (Ba1−x−ySryEux)9Sc2Si6O24 (x=0.005–0.1, y=0–0.95), have been successfully prepared by solid-state reaction at 1350 °C. The analysis of X-ray diffraction shows that the compounds are in a single phase at the proper concentration of Sr2+. At room temperature, the Eu2+-activated Ba9Sc2Si6O24 phosphor exhibits a single emission band peaking at about 506 nm. With the increasing content of Sr2+, the luminescent intensity of (Ba1−x−ySryEux)9Sc2Si6O24 weakens, and the emission peak shifts towards red. Luminescence concentration quenching occurs when Eu2+ content x is more than 1 mol% in (Ba1−x−ySryEux)9Sc2Si6O24 (y=0/0.2). At low temperatures (Ba0.9−ySryEu0.1)9Sc2Si6O24 (y=0/0.2) phosphors have two emission bands corresponding to different Eu2+ crystallographic sites. The high energy peak (P1) is quenched at room temperature, while the low energy peak (P2) weakens much more slowly owing to the energy transfer from P1 to P2.