Paper TF+EN-TuM9
Functionalized Quartz Fibers by Atomic Layer Deposition for Dye-Sensitized Solar Cells

Tuesday, November 1, 2011, 10:40 am, Room 107

Dye-sensitized solar cells (DSCs) are a promising alternative to Si-based photovoltaic cells because of their high efficiency, low cost, and simple processing. To improve the efficiency, the light harvesting properties of the DSC photoanode structure should be improved.

This work shows the ability to improve DSCs efficiency by the incorporation of quartz fiber mats functionalized by ALD with a conformal nanoscale TiO₂ coating for the photoanode. The TiO₂ atomic layer deposition allows precise nanoscale thickness control throughout the quartz fiber mat. In addition, thermal stability of the quartz fiber also enables the annealing of TiO₂ films at high temperatures in order to obtain anatase crystallinity, which is the preferred TiO₂ phase in DSCs due to faster electron transfer kinetics. As a result, we obtained very stable anatase TiO₂ on quartz fibers by annealing at as high as 1050 °C. The micro-sized randomly oriented structure of coated quartz fibers caused high light scattering effect inside the photoanode, so that it increased the photon adsorption. At the same time, TiO₂-coated quartz fibers were successfully sensitized by more dye molecules compared to bare quartz fibers.

The use of the dye-sensitized quartz fiber mats in a DSC framework produces devices with overall efficiency exceeding 7% in our laboratory, compared to ~ 6% for similar devices without the coated fiber scattering layer. We will present X-ray diffraction, morphological changes, and optical properties of TiO₂-coated quartz fibers, as well as I-V and IPCE data for the DSCs. The effects of various integration schemes for introducing quartz fibers into the DSC photoanode will be discussed. Moreover, it is believed that the combination of quartz fiber and ALD is very attractive especially to energy research fields where they need finely tuned nanostructures to meet intricate requirements.