Preparation Of One-Dimensional Nanomaterials For Dye-Sensitized Solar Cell

Since the breakthrough work by Gr?tzel in 1991, dye-sensitized solar cell （DSSC） based on the TiO₂ nanoparticles have been attracting extensive attention due to its high efficiency, simple fabrication process and low cost. However, the nature of electron transport in oxide nanoparticles film is regarded as the trap-limited diffusion process, where the photogenerated electrons repeatedly interact with a random distribution of traps so that they walk randomly through the nanoparticles film. One promising option for improving the electron diffusion length in the anode is replacing the nanoparticles film with one-dimensional semiconductive nanomaterials. But lower photoelectric conversion efficiency was obtained for DSSC when one-dimensional nanomaterials as anode. For the purpose of further improving the photoelectric conversion efficiency of DSSC, solar cell was constructed based on the composites of P25 nanoparticles and single crystalline anatase TiO₂ one-dimensional nanomaterials. The inherent advantages of high surface area of P25 nanoparticles and rapid electron transport rate of single crystalline anatase TiO₂ microspheres were represented in nanoparticles /microspheres composites solar cell.TiO₂ and ZnO nanomaterials were synthesized via a facile hydrothermal route. The morphologies of as-prepared products and the crystal structures are detected by SEM and by XRD,respectively. the growth mechanisms for the results synthesized by hydrothermal method were discussed. The light scattering properties of TiO₂ nanomaterials with different morphology were characterized by the UV-Vis spectrometry. superior light scattering properties of TiO₂ nanomaterials make them promising materials for applications in the solar cells. Finally, room-temperature photoluminescence for ZnO samples with different morphology was investigated.The four different composites were obtained with 10 wt%, 20 wt%, 80 wt% and 100 wt% microspheres, respectively. And then, composites-based DSSC were fabricated and tested in simulated sunlight. Comparable performances of composite solar cell with pure P25 nanoparticles solar cell indicate that the composite solar cell shows enhanced power efficiency from 7% for pure nanoparticle cell to 7.92% for the composite cell with 10 wt% microspheres. In terms of the solar cell with 80 wt% microspheres, the current density decrease significantly because of their less compact packing. However, with the increase of film thickness, the current density shows a continuous increase. This phenomenon indicates that the electron diffusion length is improved due to the formation of microsphere divided into nanowire network during screen printing. Finally, the results show that employing nanoparticle/microsphere composites represents a promising approach for improving the efficiencies of DSSC.