| Summary: | 碩士 === 國立交通大學 === 應用化學系 === 88 === This research has successfully synthesize several series of Sr(Al1-xGax)12O19:R (x = 0, 0.5, 1; R = Eu3+, Tb3+, Cr3+ or Mn2+) phosphors at 1100 ℃ via a sol-gel route. The average grain size and specific surface area were determined to be 200-600 nm and 24.0 m2/g, respectively, as indicated by scanning and transmission electron microscopic (SEM and TEM) imaging studies. The grain size and composition distribution was found to be much narrower than those synthesized by solid state method. The λem of Cr3+ and Mn2+ activators was found to exhibit red and blue shifts with increasing x, respectively, for Sr(Al1-xGax)12O19:R (x = 0, 0.5, 1; R = Cr3+ and Mn2+) phases, as indicated by the photoluminescence spectra. These observations can be rationalized by considering the effect of host composition variation on the strength of crystal field for activator ions. No host composition effect was observed when the R ion of Sr(Al1-xGax)12O19:R was Eu3+ or Tb3+. The decay lifetime for the phosphors described above was found to be between 1 msec and 0.1 μsec that were found to agree well with those reported in the literature, as indicated by the life time decay measurements. The CIE chromaticity coordinates for these phosphors were found to be highly dependent on processing conditions of synthetic routes.
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