Study On The Preparation And Performance Of Dye-sensitized Solar Cells Based On Multilayer Composite Film Electrodes

High open circuit voltage dye sensitized solar cells based on different composition of multilayer thin film electrodes were designed and prepared in this paper. The photoelectric performance parameters have been evaluated by testing the ultraviolet-visible absorption spectra and J-V characteristic curve of solar cells. The micro kinetics mechanism of the charge separation, recombination, and charge transport, collection on TiO2/electrolyte interface in solar cells were further studied through the transient photocurrent voltage decay and electrochemical impedance technique. The thesis consists of the following two parts:(1) The nanocrystalline TiO2 was prepared by sol-gel and water bath synthesis technology combined with a controllable preparation. TiO2/CdS QDs/TiO2/amorphous TiO2/C106 hybrid-sensitized multilayer thin film electrodes were fabricated. The solar cells were fabricated based on the different structure of mesoporous Ti O2 hybrid-sensitized multilayer thin film electrodes. The results indicated that CdS QDs and C106 hybrid-sensitized layer in multilayer thin film electrode can make dye sensitization layer not be affected by short wavelength light; avoid the harm of uv light. And make effective use of uv light at the same time, CdS QDs can absorb of short wavelength light, widen overall light response range of the solar cells, and significantly increase the open circuit voltage of the solar cells. By TiCl4 post-treatment on the surface of electrode to form a functional layer of TiO2 which can effectively prevent the reaction between CdS QD and electronic I3-/I-, increase efficiency of electronic injection of nanocrystalline TiO2, and improve the optical electronic transport speed between TiO2 nanocrystals. CdS QD layer can reduce the charge recombination rate, further improve the photoelectric performance parameters of the solar cells based on cooperative sensitized electrodes.(2) The new core- shell structure of Ag/TiO2 was synthesized with diameter of 85 nm Ag nanowires in the inner core and TiO2 shell thickness of about 95 nm under liquid mild conditions. The solar cells were fabricated based on Ag/TiO2 and nanocrystalline TiO2 mixed multilayer sandwich membrane electrodes. The results indicated that the Ag nanowires in Ag/TiO2 had good electrical conductivity and chemical stability. An electron transport channel have been set up with Ag nanowires structures, which can effectively reduce reaction between electrons and holes, and electrolyte composition, greatly improve the electronic life and electronic diffusion length, high density of charge layer forms at the interfaces, the high open circuit voltage of the solar cell obtained. Although the introduction of Ag/TiO2 layer reduces the surface of the thin film electrode and the ability of light harvesting, but significantly improves electronic transmission performance. A amorphous layer of TiO2 can prevent the surface of Ag nanowires contacting with the electrolyte directly and becoming the composite center, improving electron collection efficiency, and further enhancing the short circuit current density and the photoelectric conversion efficiency of the solar.