Relationships between structural and luminescence properties in Eu3+-doped oxyphosphate-silicate apatite Ca2-xLa8-x(SiO4)6-x(PO4)xO2

The present paper reports the Eu3+ fluorescence in the continuous solid solution Ca2+xLag-x(SiO4)(6-x) (PO4)(x)O-2 (x = 0, 3, 6) of the apatitic phosphate-silicates M-10(XO4)(6)Y-2 with M = Ca: La/X = P, Si and Y = O. Selective UV laser excitation, site-selective-laser excitation in the D-5(0) level have been performed at 300 and 77 K D-5(0) level decay times have been reported. In these compounds, Eu3+ can be observed in the three crystallographic positions Ca(I), Ca(II) and La(II) of the two cationic sites labeled M(I) (4f) C-3 symmetry and M(II) (6h) C-s symmetry. The dominant one is found M(II) due to an Eu - O privileged bonding with Eu3+ located in (6h) positions either in La(II) or in Ca(II). (C) 2001 Elsevier Science B.V. All rights reserved.