Effect of Fe, Co, Ni and Cd CO‒activation on luminescence emission and decay of CaS:Ce phosphors

Abstract

Cathodoluminescence (CL), photoluminescence (PL), thermoluminescence (TL) spectra, and decay after laser beam excitation of cerium-activated CaS phosphors doped with Fe, Co, Ni or Cd have been investigated. These studies shed some light on the nature of luminescence centres and the association of various groups of traps with the dopants. Effect of concentiation variation of these four elements on emission and decay characteristics of CaS:Ce phosphor has been discussed. In contrast with the earlier publication [W. Lehmann and F. M. Ryan, J. Electrochem. Soc. 119, 275 (1972)] we have found that Ni is an effective killer, Cd ineffective and Co has no clearly observable effect. Fe has also been found to be an effective killer for CaS:Ce phosphors. Ni and Fe appear to be more effective quenchers for shorter wavelength emission band characteristic of Ce in CaS.