| Summary: | 碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系 === 97 === The purpose of this study is to synthesize high quality inorganic materials that can provide good optical properties for dye-sensitized solar cell (DSSC). Three nanometer-sized semiconductor particles including CdSe, ZnO, and TiO2 have been prepared. And their basic spectroscopic and structural characterizations have also been completed. Firstly, we prepared CdSe aqueous solution at low temperature by wet chemical method, the synthesized CdSe nanoparticles (app. 5-15 nm diameter) display hydrophilic-rich property by modifying their surfaces with thioglycolic acid (TGA), which is used as stabilizer to protect CdSe and prevent precipitation occurrence from the aggregation of CdSe particles. The UV-vis absorption and fluorescence emission spectra appear in the wavelength of 350-550 nm and 500-600 nm, respectively. However, the spectra show a red shift when the particle size is increased with increasing of reaction time. Additionally, the CdSe shows a negative zeta-potential and which also increases with increasing pH of the solution.
Furthermore, TiO2 nanoparticle prepared by sol-gel method possesses not only a higher specific surface area and mesoporous structure but also has the capability of strongly adhering to ITO glass. Finally, ZnO powder (app. 50 nm diameter) is also synthesized using co-precipitation method and characterized with various analysis instruments. Compared to TiO2 nanoparticle, the UV-vis absorption peak of ZnO locates on the wavelength of 385 nm that get closer to visible light.
The CdSe/TiO2 photo-electrode is prepared by immersing TiO2 electrode into CdSe aqueous solution for a period of time and examines its current efficiency. The experimental results show that mixing 2-5 percentages of ZnO powder to the TiO2 sludge not only can increase the film thickness from 4-6 m to 15-18 m, but also can increase the absorbed amounts of CdSe solution, thus improve the photovoltaic performance of DSSC. Furthermore, it is found that the power output (current-voltage) characteristics using the above-prepared CdSe/TiO2 as a photo-electrode of DSSC exhibit Isc = 64 A and Voc = 134 mA.
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