| Research Abstract |
Investigators of this project have been studying on the development of ultra fine particle phosphors with high performance for field emission displays (FEDs). In this project, the phosphors such as SrTiOィイD23ィエD2:Pr, Al, YィイD22ィエD2OィイD22ィエD2S:Eu , SnOィイD23ィエD2:Eu, TiOィイD22ィエD2:Eu, YィイD22-XィエD2ZnィイD2XィエD2OィイD23ィエD2:Eu etc. were prepared with fine particle sizes by sol-gel.
To obtain high luminance from SrTiOィイD23ィエD2:Pr red emitting, the addition of Al to the phosphor is necessary. When the Al addition is 30 mol%, which is optimum in this investigation, the SrTiOィイD23ィエD2:Pr, Al phosphor shows a luminance of 34 cd/mィイD12ィエD1 and CIE color coordinates of (0.681, 0.314) under excitation with 2 kV and 108 μA/cmィイD12ィエD1 cathode. It was shown for the first time for the mechanism of the effect of the Al addition that (1) almost all of the added Al distribute as AlィイD22ィエD2OィイD23ィエD2 on the phosphor surface observed by specific X-my image of SEM, (2) Al introduced into SrTiOィイD23ィエD2 bulk cont
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ributes for the improvement of luminance by forming 4 coordination observed by nuclear magnetic resonance measurement.
YィイD22ィエD2OィイD22ィエD2S:Eu phosphor with particle size smaller than 0.5 μm could be synthesized successfully. The particle size is smaller than that of phosphor on the market. Moreover, the phosphor shows a luminance of 320 cd/mィイD12ィエD1 color coordinates of (0.648, 0.342) under excitation with 1 kV and 60 μA/cmィイD13ィエD1. The luminance is higher than that of commercial phosphor. It was found for the synthesis of SnOィイD22ィエD2:Eu phosphor that the phosphor with smaller particle size and showing luminance with 20 times was successfully obtained using ethanol as solvent for SnC1ィイD24ィエD2 and EuClィイD23ィエD2 than the phosphor prepared in water. It was found for the first time that the crystallinity and luminance of the YィイD22ィエD2OィイD23ィエD2:Eu phosphor increases considerably by the addition of Zn. The phosphor added with 5 mol% Zn showed a luminance of 1000 cd/mィイD12ィエD1 and CIE color cordinates of (0.643, 0,345) under excitation with 2 kV mid 60 mA/cmィイD12ィエD1, and those data are promising for the commercial use. Less
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