Study On Large-sized Dye-sensitized Solar Cells

As a new type of solar cell, dye-sensitized solar cell (DSC) is an alternative to silicon solar cells on the basis of low cost, simple production technology, pollution-free and rich in raw materials. Currently, the photoelectric conversion efficiency of small area DSC is close to the level of amorphous silicon solar cell. However, there are problems such as low efficiency and poor long-term stability for large-sized DSC. Therefore, we need to study the large-sized dye-sensitized solar cell to achieve the industrialization of DSC. We need to improve production methods, design and develop a new type of large-sized DSC to resolve the current problems of large-sized DSC.In this thesis, five kinds of large-sized DSCs were designed and fabricated, including the single DSC, parallel DSC, series W-DSC, series Z-DSC and X-DSC. X-DSC is a new type of large-sized DSC developed by our group. Firstly, the photoelectric conversion efficiency and electrochemistry impedance spectroscopy were studied. The results showed that the Ag grids printed on the conductive substrates can improve the efficiency of large-sized DSC obviously. The Ag grids improve the fill factor (FF) of large-sized DSC by reducing the resistance of conductive substrate. Consequently, the efficiency of large-sized DSC is improved. Secondly, we studied on the influencing factors of large-sized DSC. The results showed that the production method of large-sized DSC was layer by layer to product TiO2 films and they were treated with TiCl4. For the large-sized DSC with an area of 4.9 cm×7.2 cm, a photoelectric conversion efficiency of 5.15%was obtained. Active area, the thickness of the platinum on the counter electrode and the concentration of electrolyte are important for affecting factors of DSC in series. Finally, we improved the production techniques to improve the long-term stability of large-sized DSC. The stability of the large-sized DSC with an area of 4.9 cm×7.2 cm was fabricated and the efficiency of the DSC was not reduced from December 2009 to April 2010 and the optical properties were stable. We also assembled the large-sized DSC module with an area of 46 cm×63 cm for 1.5 years now, and its stability has been commendable.The photoelectric conversion efficiency and electrochemistry impedance spectroscopy of the X-DSC were studied. The results showed that X-DSC can be carried out different series and parallel connections to meet different needs. Compared with the conventional parallel DSC, a 33.62%of enhancement in the efficiency was achieved for the X-DSC developed by our group. Consequently, X-DSC is a promising large-sized DSC, and it lays a solid foundation for the industrialization of large-sized DSC.