The Application of Electrospun Titania Nanofibers in Dye-sensitized Solar Cells
Titania nanofibers were fabricated using the industrial Nanospider (TM) technology. The preparative protocol was optimized by screening various precursor materials to get pure anatase nanofibers. Composite films were prepared by mixing a commercial paste of nanocrystalline anatase particles with the electrospun nanofibers, which were shortened by milling. The composite films were sensitized by Ru-bipyridine dye (coded C106) and the solar conversion efficiency was tested in a dye-sensitized solar cell filled with iodide-based electrolyte solution (coded Z960). The solar conversion efficiency of a solar cell with the optimized composite electrode (eta = 7.53% at AM 1.5 irradiation) outperforms that of a solar cell with pure nanoparticle film (eta = 5.44%). Still larger improvement was found for lower light intensities. At 10% sun illumination, the best composite electrode showed eta = 7.04%, referenced to that of pure nanoparticle film (eta = 4.69%). There are non-monotonic relations between the film's surface area, dye sorption capacity and solar performance of nanofiber-containing composite films, but the beneficial effect of the nanofiber morphology for enhancement of the solar efficiency has been demonstrated.