Red emitting MTiO3 (M = Ca or Sr) phosphors doped with Eu3+ or Pr3+ with some some cations as co-dopants

Abstract

[EN] Ca (or Sr)TiO3:Eu3+ , M (Li + or Na+ or K+ ) and CaTiO3:Pr 3+ , M (Li + or Na+ or Ag+ or K+ or Gd3+ or La3+ ) powders were prepared by combustion synthesis method and the samples were further heated to !1000 !C to improve the crystallinity. The structure and morphology of materials were examined by X-ray diffraction (XRD) and a scanning electron microscopy (SEM). The morphologies of SrTiO3:Eu3+ , CaTiO3:Eu3+ or CaTiO3:Pr 3+ powders co-doped with other metal ions were very similar. Small and coagulated particles of nearly cubical shapes with small size distribution having smooth and regular surface were formed. Photo-luminescence spectra of CaTiO3:Pr 3+ and co-doped either with Li + , Na+ , K+ , Ag+ , La3+ or Gd3+ ions showed red emissions at 613 nm due to the 1 D2 ? 3 H4 transition of Pr 3+ . The variation of intensity of emission peak with different co-doping follows the order: K+ > Ag+ > Na+ > Li + > La3+ > Gd3+ . The characteristic emissions of CaTiO3:Eu3+ lattices had strong emission at 614 and 620 nm for 5 D0 ? 7 F2 with other weak transitions observed at 580, 592, 654, 705 nm for 5 D0 ? 7 Fn transitions where n = 0, 1, 3, 4 respectively in all host lattices. Photoluminescence intensity in SrTiO3:Eu3+ is more than CaTiO3:Eu3+ lattices. A remarkable increase of photoluminescence intensity (in 5 D0 ? 7 F2 transition) was observed if co-doped with Li + ions in CaTiO3:Eu3+ and SrTiO3:Eu3+ . " 2013 Elsevier B.V. All rights reserved.