Red emitting MTiO3 (M = Ca or Sr) phosphors doped with Eu3+ or Pr3+ with some cations as co-dopants
Ca (or Sr)TiO3:Eu3+, M (Li+ or Na+ or K+) and CaTiO3:Pr3+, M (Li+ or Na+ or Ag+ or K+ or Gd3+ or La3+) powderswere prepared by combustion synthesis method and the samples were further heated to similar to 1000 degrees 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:Pr3+ 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:Pr3+ and co-doped either with Li+, Na+, Ag+, La3+ or Gd3+ ions showed red emissions at 613 nm due to the D-1(2) -> H-3(4) transition of Pr3+. 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 D-5(0) -> F-7(2) with other wealctransitions observed at-580, 592; 654, 705 nm far D-5(0) -> F-7(n) 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 D-5(0) -> F-7(2) transition) was observed if co-doped with Li+ ions in CaTiO3:Eu3+ and SrTiO3:Eu3+. (C) 2013 Elsevier B.V. All rights reserved.
catio3:pr3+ combustion synthesis srtio3:eu3+ catio3:eu3+ m+ (li+, na+ or k+) charge compensators