The electroluminescence (EL) properties of SrS:Cu, SrS:Ag, and SrS:Ag,Cu thin-film phosphors are reported. SrS:Cu and SrS:Ag are shown to exhibit very different EL properties with SrS:Cu possessing a luminance and efficiency of 30.8 cd/m2 and 0.2 lm/W, compared to SrS:Ag whose luminance and efficiency are 0.7 cd/m2 and 0.001 lm/W, respectively. In contrast, SrS:Ag,Cu exhibits the high luminance and efficiency of SrS:Cu, but the saturated chromaticity of SrS:Ag, which exhibits an excellent blue chromaticity of (0.17,0.15). The improved electroluminescent luminance, efficiency, and color purity of SrS:Ag,Cu are explained by the energy transfer from the Cu+ to Ag+ ions. These results suggest a concept to improve EL performance through the use of a class of two-component phosphors, which exhibit superior color, brightness, and excitation efficiency. © 1999 American Institute of Physics.