| Nowadays, energy and environment are both of the two important strategies for the development of human society in the world. We should protect the environment to keep the sustainable development of the human society when we solve the energy crisis. So we must find a new kind of clean energy for sustainable utilization. The solar energy is one of the most potential energy for its continuous irradiation and no pollution. The traditional silicon solar cells haven't been widely used because of its complicate manufacture and expensive costs. Dye-sensitized solar cell (DSSC) is a new kind of solar cell, which is low cost, easy fabrication and with long lifetime, etc. since the breakthrough made by Professor Gratzel's research group in 1991, more and more researchers have been attracted to study in this area. Development of anode material is one of the most important research fields in DSSC. And titania is considered to be the most effective anode material at present, and its higher conversion efficiency is influenced a lot by the way of optimizing the TiO2 electrodes. The optimization of TiO2 electrodes in DSSC contains:design of new nanostructure, addition of scattering layer, complex structure, surface treatment, elements doping etc. This study has focused on TiO2 electrodes, to study the influence of surface treatment and nanostructure design on the photoelectric performance of DSSC. The investigation works are as follows:Diluted TiCl3 aqueous solution is used for the surface treatment on TiO2 electrode. Compared with the samples without TiCl3 treatment, the treated samples demonstrate tiny change on microstructure and decreased surface area. Simultaneously, it is found that the TiO2 film absorbs less dye molecule after TiCl3 treatment, but shows a higher short circuit current density and photoelectric conversion efficiency. The open-circuit photovoltage decay (OCVD) measurement is conducted for investigating the mechanism inside solar cells. And the electron lifetime is prolonged in the TiO2 film after TiCl3 treatment. This indicates a decreased recombination between electron and electrolyte, thus increasing the current density and conversion efficiency. Compared with the traditional TiCl4 treatment method, this method is easy to operate, without ice bath, and an obvious effect is achieved.Tetrabutyl titanate and titanous trichloride solution (15wt%) are used as the two titanium precusors for the synthesis of titania. After mixing them together, we use one step hydrothermal treatment to synthesize composite nanostructure with nanoparticles and nanorods TiO2, which are also mixed phase structure. Combining with the SEM results, the formation mechanism of this material is discussed. We also compare the photoelectric performance of this composite nanostructure TiO2 with commercial TiO2-P25, which are both used as the anode material in DSSC. By using the impedance method, it is found that the electron transport is faster in composite nanostructure TiO2 film than that of P25 film, and the electron lifetime is also prolonged. This increases the current density, thus improving the conversion efficiency. Besides, this synthesis method needs less energy, and the nanorods are mixed well with the nanoparticles.
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