Preparation And Study Of Composite Photo Anodes For Dye - Sensitized Solar Cells

Energy is a core element of national economic development and strategic resources, is to improve the living standards of the people important material basis, which can direct impact on national security, sustainable development and social stability. However, the potential of non-renewable and polluting the environment, so the development of sustainable clean energy is an effective way to solve our energy crisis and environmental pollution. Since dye sensitized solar cell (DSSCs) is introduced in1991by Swiss scientist Gratzel and coworkers, and the initial efficiency is7.1%, which has got a considerable development in the past two decades owing to their high efficiencies and low cost. Though the photovoltaic conversion efficiency of cell has achieved13%, it still poorer than the theory of conversion efficiency. So, in this thesis, the photo-anode film of cell was fabricated and studied to improve the performance of DSSCs. Moreover, the flexible DSSCs also was studied and discussed. Main research results in this paper were summarized as follows:(1) A novel tri-layered ZnO nanostructure as photoanode for DSSCs was fabricated and studied. ZnO NWs were prepared via a two-step synthetic approach which as the bottom of the cell. A small ZnO hierarchical microspheres (S-ZnO HMSs) were used as the intermediate layer and a large size ZnO hierarchical microspheres (L-ZnO HMSs) were used as overlayer. It can be observed the S-ZnO HMSs has a higher specific surface area, which can effectively improve the dye adsorption amount of anode film, meanwhile enhance the properties of light scatteiing. Otherwise, the L-ZnO HMSs also can improve the dye adsorption amount of anode film, what’s more, enhanced the properties of light scattering. As a result, the photovoltaic conversion efficiency of DSSC based on the tri-layered ZnO photoanode obtained the highest photovoltaic conversion efficiency (3.21%).(2) SrTiO3was prepared via a simple hydrothermal method, and was used in the scattering layer of cell. It was bulk with the average around diameter200-400nm by scanning electron microscopy, which is very suitable for scattering layer. We found that the photoelectric property of monolayer SrTiO3is better than double SrTiO3. On the one hand, the scatting property is enhanced by added double SrTiO3. On the other hand, the dye adsorption amount of cell is reduced because of the densely packed top layer of large SrTiO3particles may make the dye molecules more difficult to diffuse into the TiO2porous layers efficiently. The two factors decide this result.(3) A new-type DSSCs based on flexible foam nickel was prepared and studied. It is very benefit to enhance the absorption of light because of the novel structure. However, the p-type oxides (NiO) limit the photoelectric conversion efficiency of the flexible DSSCs, due to the high temperature treatment in the process of preparation. So, the result is unsatisfactory which load to seek a new foam metal or improve the new preparation technology.