| Summary: | 碩士 === 逢甲大學 === 材料科學所 === 98 === ZnO (Zinc oxide, ZnO) nanostructures have been synthesized using ultraviolet and thermal decomposition process in ambient air, which is simple process, low cost, and short process time (only require ten minutes). As-synthesized ZnO nanostructures have been addressed to characterize the photoresponsive and photocatalytic properties.
All as-synthesized products were characterized using field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffractometer (XRD), and X-ray photoelectron spectroscopy (XPS). In addition, a UV detection system was used to investigate the sensing activities of as-synthesized ZnO nanostructures while the ultraviolet-visible spectrophotometry (UV/vis, Hitachi U-3900 double-beam spectrophotometry) was performed to determine the photocatalytic activities of the as-synthesized products.
Zinc acetylacetonate hydrate【Zn(AcAc)2】 was acted as solute while isopropyl alcohol (IPA), denatured alcohol, ethanol and acetone were used for solvent to prepared the Zn(AcAc)2 precursors. The UV-light (~365nm, 76mW/cm2) was used as light-source while the electronic furnace system was used as thermal-source to decompose the Zn(AcAc)2 precursors with process temperature ~ 200oC to synthesize the ZnO nanostructures. This work revealed that as-synthesized ZnO nanostructures (with IPA solvent) exhibited an ultra-high sensitivity ~809 folds as irradiated the sample to UV-light (~365 nm, 2.33 mW/cm2). Photoluminescence (PL) spectra demonstrated that the photoresponsive properties were proportional to the intensity of ZnO emission band (~380nm).
In addition, the high surfaces to volume ratio of ZnO nanowires can be successful synthesized by UV decomposition and thermal decomposition process with process time ~ 10 minutes. The precursor is Zn(AcAc)2 with the solvent of denatured ethanol while through thermal decomposition for 3 minutes. To investigate the photocatalytic properties, as-synthesized ZnO nanowires with methylene blue (MB, C16H18ClN3S•H2O, 10μM) solution were irradiated under UV-light (254 nm, 3.15 mW/cm2) for 20 minutes. The highest dye decolorization efficiency (90% in 20 minutes ) was observed. The photocatalytic property of as-synthesized ZnO naowires is superior to that of commercial P25 TiO2 nanparticels. This work is developing a simple process, short process time, large scale, and cost of facilities-based investment. These unique advantages demonstrate that as-synthesized ZnO nanostructures probably possess the highly potential applications in novel optoelectronic devices.
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