Alkali metal coactivators in SrS: Cu,F thin-film electroluminescent devices
نویسندگان
چکیده
A unique approach for obtaining bright and efficient saturated green phosphors for alternating-current thin-film electroluminescent ~ACTFEL! device applications is presented. The approach involves color-shifting blue SrS:Cu,F ACTFEL phosphors into the green region of the spectrum via the incorporation of alkali metal ions into the SrS lattice. Alkali metals are incorporated into SrS:Cu,F phosphors by using LiF, NaF, KF, RbF, or CsF coactivators. The best result to date is obtained by using a KF coactivator and results in a saturated green brightness and efficiency of 52.7 cd/m and 0.973 lm/W ~at a frequency of 60 Hz and an overvoltage of 40 V!. In addition to providing a color shift, the alkali-metal fluorides improve the overall performance of the ACTFEL device by increasing the magnitude of the electric field and its uniformity across the phosphor through suppression of positive space charge. © 1999 American Institute of Physics. @S0003-6951~99!04736-1#
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