A FACILE ROUTE TO DYE-SENSITIZED SOLAR CELLS WITH A SINGLE LAYER DEPOSITION OF SKEIN-LIKE TIO_2 NANOTUBES

摘要

We present a new TiO_2 morphology, featuring high surface area and open structure, synthesized by a new two-step chemical route for dye-sensitized solar cells (DSSCs) applications. This construct is sets of intertwined nanotubes, so called skein-like nanotubes. The skein-like morphology enables to eliminate the conventional four-fold layer deposition process by a single layer deposition of TiO_2 nanotubes. Such morphology enhances photon capture of fabricated DSSC by exerting a triple function mechanism including improvement of light scattering, dye sensitization and electron transport. The grown skein-like TiO_2 nanotubes using mesoporous nanoparticle precursor, synthesized by TiC oxidation at 70°C followed by annealing at 400°C, shows high open structure with narrow diameter size distribution. The fabricated cell made of a single layer of that product shows power conversion efficiency (PCE) of 5.53%. A double layer solar cell containing under layer of nanoparticles and over layer of 50% nanotubes and 50% nanoparticles shows PCE of 6.37%. These are one of the highest PCEs reported for single and double layer solar cells of randomly oriented nanotubes.