Study On Dye-sensitized Solar Cells Based On The Anode Films With One-dimensional Nanostructure

Dye-sensitized solar cells (DSSC) have attracted extensive interest as a novel solar cell due to their advantages of low cost, no pollution, simple preparation process and relatively high energy conversion efficiency. The photoanode is a key component of DSSC and it acts as a scaffold for the dyes and a transfer media for photogenerated electrons from dyes to the F-doped tin oxide (FTO) layer. The ability of dye absorption and electronic transmission are the key factors to determine the photoelectric conversion efficiency of DSSC. Generally, traditional photoanode in DSSC is made up of TiCh nanoparticle film with large specific surface areas. However, electron scattering and trapping in the grain boundaries among nanoparticles seriously influence DSSC performance in the case. Vertically aligned one-dimensional nanostructures can effectively reduce the influence of grain boundary and surface state, due to their advantages of efficient electronic transport channel. This thesis focuses on the one-dimensional photoanode as following.Firstly, single-crystal vertically aligned TiO2nanorod arrays (TNRs) were synthesized directly on FTO glass through solvothermal method. By adjusting the ratio of precursors, reaction temperature, and reaction time, the relationship between the film structure and reaction parameters were studied. Then the influence of film structure on the performance of the DSSC was studied. The optimized parameters (the molar ratio of n-hexane, tetrabutyl titanate and hydrochloric acid is77:4:11, reaction temperature is180℃, and reaction time is15h) for the highest photoelectric conversion efficiency have been found.Secondly, the effects of annealing on the structure of TiO2nanorods and cell efficiency have been studied. The results indicate that the crystal structure of TiO^nanorods did not change after thermal treatment, but a surface reconfiguration from one thin amorphous TiO2layer to tiny crystallites spheres occurred. Moreover,the adsorbed water and residual n-hexane on the TiO2surface disappeared, which lead to the increases of dye adsorption by20.5%. Moreover, the electron transport was also improved due to the decrease of bulk and surface defect concentration. All of these lead to a39%improvement of photoelectric conversion efficiency for the nanorod-based DSSC.Finally, Au@C core/shell nanostructures were prepared using one step hydrothermal. Au@TiO2spheres were prepared from TiCl4ethanol solution coating using Au@C core/shell nanostructure as template. The characteristics of light absorption were studied and an obvious absorption peak at580nm was found. The surface plasmon enhanced absorption could be applied in the DSSC and higher efficiency might become possible.