Nb, F-didoped titanium micro-beads used in dye sensitized solar cells

Photoanode semiconductor materials are modified to improve the performance of dye-sensitized solar cells (DSSCs). Niobium and fluorin didoped titanium dioxide (NFT) micro-beads that contain multilayer nanotubes and nanoparticles are synthesized via a one-step sol-gel hydrothermal method. The surface area of these beads is increased by the special nano-structure, so as the adsorption of dye is promoted. In addition, the crystallinity of NFT is increased with the increase of doping content compared to undoped titanium dioxide, which improves the electronic diffusion and reduces the surface polarization. As a result, the open circuit voltage and short circuit photocurrent density of DSSCs are increased. Tests on monochromatic incident photon-to-electron conversion efficiency (IPCE) show that the optical quantum efficiency of NFT fabricated DSSCs is improved significantly at visible light region and is also enhanced at ultraviolet range. Consequently, the overall conversion efficiency of the DSSCs with NFT has a 38% increase over that of DSSCs with undoped TiO ₂.