Tuning luminescent properties through solid-solution in (Ba1-xSrx)9Sc2Si6O24:Ce3+,Li+

A solid-solution of cerium-substituted alkaline earth scandium silicate phosphors, (Ba1-xSrx)9 Sc2Si6O24:Ce-3,Li+ (x = 0, 0.25, 0.50, 0.75, 1), have been prepared by solid-state reaction. The structures, characterized using synchrotron X-ray powder diffraction, show the solid-solution closely follows Vegard's law. The substitution of Sr for Ba results in a decrease of the alkaline earth-oxygen bond distances by more than 0.1 angstrom at all three crystallographic sites, leading to changes in optical properties. The room temperature photoluminescent measurements show the structure has three excitation peaks corresponding to Ce3 occupying the three independent alkaline earth sites. The emission of (Ba1-xSrx)9 Sc2Si6O24:Ce3+,Li+ is red-shifted from the near-UV (lambda(max) = 384 nm) for x = 0 to blue (Amax = 402 nm) for x = 1. The red-shifted photoluminescent quantum yield also increases when Sr is substituted for Ba in these compounds. (C) 2013 Elsevier Masson SAS. All rights reserved.