SYNTHESIS OF CaWO 4 AND CaWO 4 :Eu MICROSPHERES BY PRECIPITATION

다국어 초록 (Multilingual Abstract)

Nearly monodisperse CaWO 4 and CaWO 4 :Eu 3 þmicrospheres have been synthesized in largescale by a surfactant-assisted solution route, in which cetyltrimethyl ammonium bromide(CTAB) is used. X-ray di®raction (XRD), scanning electron microscopy (SEM), Fourier trans-form infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and photo-luminescence (PL) were used to characterize the resulting samples. The results of XRD indicatethat the CaWO 4 and CaWO 4 :Eu 3 þsamples have the scheelite structures. The growth process ofthese nearly monodisperse spheres with an average diameter around 3.2 ? m has been examined. The results of FTIR indicate that CTAB plays an important role in the formation of micro-spheres. The CaWO 4 microspheres exhibit a blue emission band with a maximum at 423 nm. Butthe CaWO 4 :Eu 3 þmicrospheres exhibit a red emission band with a maximum at 623 nm.

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