| Summary: | 碩士 === 國立交通大學 === 應用化學系碩博士班 === 103 === In this study, we have successfully synthesized several new red-emitting phosphors with compositions of Sr2TiSi2O8:Mn2+, Sr2Ti2Si4O14:Mn2+, BaGe2.5Si1.5O9:Mn4+, and green-emitting phosphors with compositions of BaGe2.5Si1.5O9:Eu2+, Ba2TiSi2O8:Eu2+ and Ba4La6O(SiO4)6:Eu2+ by using PGMS/sol-gel and microwave-assisted synthetic methods, which may shorten the preparation time of tedious sol-gel method. The crystal structure, luminescence, chromaticity properties and thermal luminescence quenching behaviors of the above phosphors were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL) and UV/Vis spectroscopy.
The first part of this thesis reports the optimization of synthetic conditions for all novel silicate-derivative phosphors, and analyzing the XRD profiles and SEM images. Secondly, we discuss the optimization of dopant concentration of the activator for various phosphors, luminescence properties, chromaticity coordinates, diffuse reflectance spectroscopy and thermal quenching effect. The last part of this study investigated the use of as-prepared phosphors and complementary commercial phosphors with near UV-LED chips to fabricate white-light LED (WLED) and studied the luminescence characteristics, chromaticity and color temperature performances. The red-emitting Sr2TiSi2O8:Mn2+ and Sr2Ti2Si4O14:Mn2+ phosphors were utilized to fabricate a WLED device with yellow-emitting Ba2SiO4:Eu2+, blue-emitting BAM:Eu2+, and a 380 nm near-UV LED chip. In addition, the green-emitting BaGe2.5Si1.5O9:Eu2+, Ba2TiSi2O8:Eu2+, and Ba4La6O(SiO4)6:Eu2+ phosphors were utilized to fabricate a WLED device with blue-emitting BAM:Eu2+, red-emitting Sr2Si5N8:Eu2+ with corresponding near-UV chips with wavelengths of 365 -385 nm. These results suggest that the new phosphors developed herein are potentially useful for trichromatic WLED application.
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