Enhanced Conversion Efficiency in Dye-Sensitized Solar Cells Based on Bilayered Nano-Composite Photoanode Film Consisting of TiO_2 Nanoparticles and Nanofibers

摘要

Novel TiO_2 nanoparticlesanofibers (NPs/NFs) bilayered nano-composite photoanode film for dyesensitized solar cells (DSSCs) was fabricated through the combination of spin-coating and electro-spinning. The NPs and NFs layers have complementary roles. The underlaid spin-coated NPs layer provides the photoanode film with higher specific surface area for dye adsorption and improved adhesion to conductive glass substrate. The overlaid electrospun NFs layer endows the photoanode film with better dye-loading and light-harvesting capabilities due to its porous meshwork structure. And the NFs layer also offers larger pore volume, which can facilitate the electrolyte diffusion and the activity regeneration of dye sensitizers. As a result, the electron transport is accelerated while the charge recombination is suppressed. Ascribing to the synergic effect of the NPs and NFs layers, the TiO_2 NPs/NFs-based DSSCs achieve a conversion efficiency of 4.46%, which is nearly 14% higher than that of the pure TiO_2 NPs-based ones.