The luminescence characteristics of a two-component electroluminescent (EL) phosphor, SrS:Cu,Ag, were investigated by optical spectroscopy. Motivated by the discovery of efficient EL from SrS:Cu, SrS:Ag was investigated but exhibited poor EL emission, even though it showed a superior blue color. Thus, SrS:Cu,Ag samples were prepared in order to investigate if the Ag luminescence could be sensitized to produce a more efficient and saturated blue EL phosphor. A detailed spectroscopic study on SrS:Cu,Ag revealed that the emission characteristics of SrS:Cu,Ag were identical to SrS:Ag, whereas the excitation spectra resembled SrS:Cu. These results demonstrated the efficient energy transfer from Cu to Ag, confirming the successful sensitization. © 1999 American Institute of Physics.