SYNTHESIS AND CATHODOLUMINESCENCE OF ORANGE-YELLOW-EMITTING TO RED-EMITTING CA1-XMGXS-MN PHOSPHORS

A complete series of single-phase Ca1-xMgxS:Mn phosphors have been synthesized by firing in an H2S/PCl3 atmosphere at 1200-degrees-C. The cathodoluminescence of these compounds has been investigated at room temperature. The emission color varied from orange-yellow to deep red as the concentration of magnesium was increased. For composition Ca0.75Mg0.25S:Mn (0.1 a/o) a highly saturated red emission was obtained with chromaticity coordinates of x = 0.657, y = 0.341, which are comparable to the commercial red phosphor Y2O2S:Eu (x = 0.650, y = 0.342). The quantum efficiencies of the end members of the Ca1-xMgx:Mn series were the highest. As substitution was increased, the quantum efficiency rapidly decreased with the lowest values in the 0.25 less-than-or-equal-to x less-than-or-equal-to 0.50 range. In addition, the presence of chloride a deleterious effect on the emission intensity; however, the chromaticity remained unchanced. Factors influencing the manganese ganese emission are discussed in