Luminescent properties of rare-earth (Eu3+ Eu2+, and Ce3+) doped apatitic oxyphosphosilicates

The luminescence of (Eu3+, Ce3+ and Eu2+) doped apatitic phosphosilicates is studied at either 300 and 77K. Samples of Ca5La5(SiO4)(3)(PO4)(3)O-2:Ln(2%) where Ln = Eu3+, Ce3+ and Eu2+, were synthesized by solid-state reaction at high temperature (1400degreesC) and then identified by the X-ray diffraction method. The rare-earth cations were found to occupy two cationic sites labeled M(I) and M(II) with a local symmetry C-3 and C-s, respectively. In comparison with Ce3+ or Eu2+-doped apatitic phosphates, the bands observed in the emission spectra of Ca5La5(SiO4)(3)(PO4)(3)O-2:Ce3+ (2%) and Ca5La5(SiO4)(3)(PO4)(3)O-2:Eu2+(2%) were found to be shifted to higher wavelength. (C) 2002 Elsevier Science B.V. All rights reserved.