| Summary: | 碩士 === 國立臺灣科技大學 === 材料科學與工程系 === 107 === Ce-doped yttrium allminum garnet (Y3Al5O12:Ce, YAG:Ce) was used as the yellow-emmiting phosphor for White light-emitting diorde (LED) due to the excellent property. The YAG:Ce phosphor powder were prepared by spray drying. Spray drying offers the advantage of homogenous particles and regular shape comparing to the common method of solid state reaction. It is well known that the organic acids plays the important role on the particle shape for the spray dried powders. In this study, precucors with various concentration (0.2 M, 0.5 M, 1 M and 2 M) of citric acid were used for preparation of YAG:Ce powder to control the morphology and improve the photoluminescence properties. The crystallite size, morphologies, particle size, specific surface area and photoluminescence property of YAG:Ce powder were examined. In addition, the formation mechanisms of various YAG:Ce powders were discussed. YAG:Ce powder treated with 1 M citric acid excibited the highest photoluminescence intensity.
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