Luminescence study of mixed valence Eu-doped nanocrystalline glass–ceramics

•Mixed valence Eu-doped glass–ceramic phosphors were produced.•Co-existence of Eu2+ and Eu3+ was ascertained from the luminescence spectra.•Environment-safe and low cost alternative phosphors are presented.

Eu-doped nanocrystalline NaAlSiO4/NaY9Si6O26 glass–ceramics have been prepared by controlled crystallization of melt quenched bulk glasses. XRD, SEM and FTIR spectroscopy techniques were employed to characterize the crystallization process and the structural properties of the precursor glass and corresponding glass–ceramics. The formation of divalent europium (Eu2+) from Eu3+ ions during high temperature synthesis under ambient atmosphere was analyzed by photoluminescence spectroscopy and is discussed using the optical basicity model. The observed luminescence properties of Eu: NaY9Si6O26 are compared with that of Eu: β-PbF2 nanocrystals and their marked differences are discussed.