| Summary: | 碩士 === 國立臺北科技大學 === 材料科學與工程研究所 === 95 === This study uses the H2S precipitation method to prepare ZnS under the room temperature, and the solid state method to dope the rare-earth ion Tb, as its activator. Then the phosphors are fired to higher than 1250℃ under protective atmosphere environment. Finally, grind the powder to 20~30um. Experimental result learn XRD and PL spectral analysis using H2S precipitation method to prepare ZnS powder. Its productivity of ZnS relatively good, but crystallization , grains of shape and luminous intensity relatively bad under pH =9. Its shape, crystallization and luminous intensity are all better, the shortcoming lies in the producing rate is unable to improve under pH =3. According to luminescence spectra, we know that ZnS:Tb(Tb:KF=1:3) phosphors which were prepared by the H2S precipitation method under pH=3 could obtain the strongest luminous intensity and get the strongest absorption peak at 347nm. The emission spectrum excited by 347nm wavelength, they showed green light wavelength range which corresponded to 5D4→7F6, 5D4→7F5, 5D4→7F4 and 5D4→7F3 transitions, respectively. Although the luminous intensity of the phosphors which prepared by H2S precipitation is lower than the luminous intensity of that prepared by TAA precipitation, we use the way that adding the rare element Ce to our phosphors in order to promoting the luminous intensity of phosphors. . According to the results, we could obtain the strongest luminous intensity when the molar fraction of Ce was reach 0.15mole%.
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