A two-component phosphor approach for engineering electroluminescence phosphors

The electroluminescence (EL) properties of SrS:Cu, SrS:Ag, and SrS:Ag,Cu th in-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/m(2) and 0.2 lm/W, compared to SrS:Ag whose luminance and effici ency are 0.7 cd/m(2) and 0.001 lm/W, respectively. In contrast, SrS:Ag,Cu e xhibits the high luminance and efficiency of SrS:Cu, but the saturated chro maticity of SrS:Ag, which exhibits an excellent blue chromaticity of (0.17, 0.15). The improved electroluminescent luminance, efficiency, and color pur ity of SrS:Ag,Cu are explained by the energy transfer from the Cu+ to Ag+ i ons. These results suggest a concept to improve EL performance through the use of a class of two-component phosphors, which exhibit superior color, br ightness, and excitation efficiency. (C) 1999 American Institute of Physics . [S0003-6951(99)01640-X].