Dye-sensitized solar cells (DSSCs) use the effect of light on dye molecules to generate electricity through a photo-electrochemical mechanism. This study aims to synthesize ano-structured DSSCs based on TiO 2 nano-particles to improve their performance and efficiency. Hence, this project studies the various manufacturing conditions of these solar cells especially in the field of specifying the optimized anodic layer thickness, producing a composite with the optimized percentage of second phase material in the anode layer and also to specify the long-term stability factor of the prepared solar cells. First, DSSCs with different thicknesses of 9, 18 and 27 µm for the anodic layer were produced and tested. The optimal thickness of anodic layer for achieving maximum conversion efficiency was determined to be 18 µm. In the next step, TiO 2 -MWCNT paste was prepared using multi-walled carbon nano-tubes as additive material. TiO 2 -MWCNT paste ithe precursor for the preparation of porous anodic film. This paste was prepared with different weight percentages (1-4wt%) of multi-walled carbon nano-tubes in titanium dioxide nano-particles. The photovoltaic and electrochemical tests, revealed that the maximum conversion efficiency is from the DSSC of composite anodic electrode with 2 wt% carbon nano-tubes. In addition, photovoltaic and electrochemical behaviors of dye sensitized solar cells based on one layer TiO 2 nano-particles, one layer TiO 2 -2%MWCNT nano-composite and bilayer TiO 2 /TiO 2 -2%MWCNT were comparatively examined. Counting the solar cell with the conversion efficiency of 2.89% as the reference, the DSSC based on TiO 2 /TiO 2 -2%MWCNT bilayer photo electrode had the conversion efficiency of 5.35% which shows 85% improvement in comparison to the reference solar cell. Furthermore, the electrochemical behaviors of these cells were examined. The results for the modeling of inner electrical circuit with the electrochemical impedance spectroscopy examinations also indicate that the generated electrons in DSSC on TiO 2 /TiO 2 -2%MWCNT bi-layer have greater electron lifetime, diffusion length, diffusion coefficient and traort resistance in anodic layer. Therefore this cell is appeared to be the most efficient DSSC in this project. Keywords: Dye Sensitized Solar Cell, TiO 2 Thin film, Composite, Nano Structure
