High-efficiency dye-sensitized solar cells based on electrospun TiO2 multi-layered composite film photoanodes

Abstract

High-efficiency DSSCs (dye-sensitized solar cells) based on multi-layered composite film photoanodes consisting of the TiO2 blocking layer, the commercial Degussa P25 nanoparticles layer and 1D (one-dimensional) TiO2 nanorods layer were fabricated. The 1D TiO2 nanorods were prepared by a simple electrospinning technology and grinding process. The photovoltaic properties of different DSSCs based on nanoparticles/nanoparticles (DNP), nanorods/nanorods (DNR) and nanoparticles/nanorods (NPR) photoanodes were investigated and their photoelectric conversion efficiencies were 6.37, 4.92 and 8.03%. The dye-sensitized solar cells based on NPR photoanodes exhibited the best photovoltaic performance with a short-circuit current of 15.7 mA cm−2. The enhanced photo-electricity performance of NPR solar cells could be attributed to the synergistic effect of following factors. (1) The P25 underlayer ensured intimate contact in DSSCs films structure and superior dye adsorption. (2) The nanorods overlayer with 1D structure showed strong light scattering ability, which significantly enhanced light harvesting efficiency. In addition, the 1D geometry of TiO2 nanorods provided a fast and long charge carrier transfer pathway, thus improving the transfer of photo-induced electrons in the DSSCs.