Luminescence Centers of Ca(S : Se) Phosphors Activated with Impurity Ions Having s2 Configuration. I. Ca(S : Se) : Sb3+ Phosphors

The emission, excitation and reflection spectra at 300, 80 and 15 K were obtained. The blue emission at 442 mµ was observed for CaS:Sb 3+ as well as the well-known yellow-green emission at 540 mµ. In the excitation or reflection spectra, A , B and C bands were found for all phosphors of Ca(S:Se):Sb 3+ investigated. These positions are 392, 345 and 321 mµ for CaS:Sb 3+ , and 428, 376 and 345 mµ for CaSe:Sb 3+ at 80 K. From these peak positions, parameters, F 0 , G , ζ and R th , were calculated with the aid of the theories known in alkali halides. The values of ζ decrease from 0.34 to 0.32 eV as the fraction of CaSe is increased. R th is about 6.8 for all the phosphors of Ca(S:Sb):Sb 3+ investigated.