EVOLUTION OF LUMINESCENCE SPECTRA OF Ce 3+ -ION IN THE SOLID SOLUTIONS Ca 1-x Sr x S

Luminescence spectra of Ce 3+ -ion in Ca 1-x Sr x S solid solutions have been investigated. It has been shown that the evolution of Ce 3+ excitation and emission spectra through the concentration range may be interpreted in correlation with the variations, with the host lattice composition, of the lattice constant, the local structure in the activator neighborhood and the band gap. Under activator excitation, in addition to the two conventional bands, an additional band peaking at about 650 nm was observed (mainly in SrS ) and was related to the contamination of the samples as a consequence of extended storage. Except for this band, the luminescence properties did not change relatively to those obtained previously on the same samples. The most drastic modification affected SrS:Ce 3+ , despite the fact that all the samples have been stored in the same conditions.