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Dye-Sensitized Solar Cells Containing TiO2 Nanoparticles and Nanowires

Bakhshayesh, Amir Mahmoud | 2012

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 43349 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Mohammadi, Mohammad Reza
  7. Abstract:
  8. Titanium dioxide (TiO2) is a transparent n-type semiconductor with wide band gap which makes it suitable for applications such as solar cells. TiO2 dye-sensitized solar cells (DSSCs) transform the visible light energy to the electrical energy by excitation of absorbed dye. In the present study, TiO2 nanowires and nanoparticles were synthesized by hydrothermal and sol-gel methods, respectively. The effect of TiO2 morphology on photovoltaic performance of the cells was studied by fabrication of single layer DSSCs containing pure nanowires, pure nanoparticles and mixture of nanowires and nanoparticles with various weight ratios. The results revealed that, DSSC made of 10 wt% nanowires and 90 wt% nanoparticles had highest cell efficiency of 4.89%. In order to investigate the effect of crystal structure of the nanoparticles, DSSCs were assembled based on mixtures of anatase and rutile nanoparticles in different weight ratios. The cell containing 20 wt% rutile and 80 wt% anatase showed the highest conversion efficiency (5.96 %) compared with the rest of the nanoparticle-based solar cells. To improve the photovoltaic characteristics of the cells, double-layers films containing nanowires and nanoparticles were prepared and the highest efficiency (6.34 %) was obtained for the film containing anatase nanoparticles as the underlayer and anatase nanowires as the over-layer. Finally, based on the obtained results a modified DSSC was designed in the form of a double-layer film with thickness of 7 μm of each layer. The designed cell was a double-layer film containing the over-layer consist of 10 %wt nanowires and the under-layer consist of 72 wt% anatase nanoparticles, 18 wt% rutile nanoparticles and 10 wt% anatase nanowires. The power conversion efficiency of the designed DSSC was measured 7.02%
  9. Keywords:
  10. Nanoparticles ; Nanowire ; Titanium Dioxide ; Dye Sensitized Solar Cells ; Sol-Gel Method ; Hydrothermal Method

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