Luminescence of Ce3+ ions in strontium haloborates

The luminescence properties of Ce3+ ions in strontium haloborates were studied upon excitation in the 3.5–22 eV region. In Sr2(1−x)Ce2xB5O9R (RCl, Br; x⩽0.01) solid solutions, two principal Ce3+ centers are observed. The dominant center was found to be produced by the direct substitution 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 vacancy. The charge compensation mechanism on the cation sublattice includes the formation of one vacancy per two Ce3+ ions incorporated. The influence of the structural features of Sr2B5O9R on the luminescent behavior of Ce3+ is discussed.