A combinatorial chemistry method was adopted to search for new Tb3+-activated green phosphors based on the phosphate system. In an attempt to apply newly found phosphors to plasma display panels, a combinatorial screening process was carried out in terms of the photoluminescence at the vacuum ultraviolet (VUV) excitation (147 nm). As a result, the optimum composition was determined to be (Gd0.74Y0.11Tb0.15)P1.15Odelta through the two-step combinatorial screening process including excess phosphorous and Gd replacement. The sample of the optimum composition showed a higher luminescence efficiency at VUV excitation and a shorter decay time than the commercially available Zn2SiO4 :Mn phosphor. (C) 2003 The Electrochemical Society.