Luminescence of Ce3+ ions in strontium haloborates

The luminescence properties of Ce3+ ions in strontium haloborates were stud ied upon excitation in the 3.5-22 eV region. In Sr2(1-x)Ce2xB5O9R (R=Cl,Br; x less than or equal to 0.01) solid solutions, two principal Ce3+ centers are observed. The dominant center was found to be produced by the direct su bstitution of the dopant ion for Sr2+ without a local charge compensation. The other center is ascribed to an associate of a Ce3+ ion and a cation vac ancy. The charge compensation mechanism on the cation sublattice includes t he formation of one vacancy per two Ce3+ ions incorporated. The influence o f the structural features of Sr2B5O9R on the luminescent behavior of Ce3+ i s discussed. (C) 2001 Elsevier Science B,V. All rights reserved.