| Field Emission Display (FED) is one of the most promising Flat Panel Display (FPD) technologies in the twenty-first century. Highly efficient phosphors with high resistance to current saturation, long service time and equal or better chromaticity than CRT phosphors are one of the keys for Field emission display (FED) technologies. The objectives of this project are to synthesize high quality red phosphor yttrium oxide (Y2O3:Eu 3+) and green phosphor strontium thiogallate (SrGa2S 4:Eu2+) and to characterize their physical properties.;Y2O3:Eu3+ was prepared by a hydrolysis technique at low process temperature. Powders prepared by this method were spherical with uniform particle size distribution. The effects of dopant concentration, particle size and calcining temperature on luminous efficiency have been investigated. The optimum performance was found for a material prepared at 2 mol. % Eu doping and 2 hour firing of 1400°C. The effects of firing temperature on particle microstructure have been studied as well.;SrGa2S4:Eu2+ was synthesized by an environmentally clean technique, in which gallium complex, europium complex, strontium sulfide and sulfur were used as raw materials and hydrogen sulfide was replaced by argon gas. A self-defining optimization method has been employed to optimize processing parameters. The effects of composition, firing temperature, firing time and annealing conditions on phosphor morphology and luminescent properties were studied. It was found that firing the phosphor at 900°C for 5 hours, and then ball-milling for 8 hours and annealing at 850°C for 5 hours gave the highest luminous efficiency. Although smaller thiogallate phosphors decreased the luminous efficiency, a significant improvement in aging performance was observed from the screens that were prepared from the smaller phosphors.;Also the unstable thiogallate phosphors were coated with several oxides to improve their aging behavior. Luminous efficiency and aging performance were measured before and after coating with oxides. |
