Fabrication and Characterization of various Monodispersed TiO2 Nanospheres for Dye-Sensitized Solar Cells

• Main Authors: Liou, Shang-En, 劉尚恩
• Other Authors: Diau, Wei-Guang
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/20529582539893812623

碩士 === 國立交通大學 === 分子科學研究所 === 98 === In this thesis, by utilizing titanium tetrachloride as precursor in water-based solution, we successfully developed a new non-hydrothermal method to fabricate monodispersed TiO2 nanosphere. By adjusting the molar ratio of magnesium chloride hexahydrate or ethylene glycol relative to the titanium precursor, a series of different size TiO2 nanospheres were produced. The structure of the nanospheres was characterized by X-ray diffraction and FESEM. The phase was identified to be rutile and the size was found to be in the range 0.3~1 μm. We found that it was difficult to control the size of TiO2 nanospheres in magnesium chloride hexahydrate solution, but much easier in ethylene glycol solution. We proposed a mechanism to rationalize the discrepancy for the two methods. Finally, by utilizing ethylene glycol, a series of monodispersed TiO2 nanospheres were produced with diameters 700±50 nm (EG5), 600±50 nm (EG10), 500±50 nm (EG15), 350±50 nm (EG20), and 250±50 nm (EG25). Using these TiO2 nanospheres as light-scattering layer in dye-sensitized solar cell, we studied how the size of the TiO2 nanospheres as light-scattering layer affecting the efficiency of a cell. Based on these results, decreasing the size of TiO2 nanospheres could increase surface area and the amount of dye loading. EG25 has the highest surface area and dye loading amount in the series of TiO2 nanospheres. However, because of its smallest size of EG25, the high transmission and low reflection reduces the effect of light-scattering, so EG25 as scattering layer did not show cell performance compared with others. The photovoltaic performance was measured under simulated AM 1.5 sunlight (100 mW cm 2). The result reveals EG20 as light-scattering layer exhibits the best cell performance reaching the power efficiency 8.75%, which is comparable to those made of commercial pastes (Ti-Nanoxide R/SP, SOLARONIX ).