Photoanode Based on Chain‐Shaped Anatase TiO 2 Nanorods for High‐Efficiency Dye‐Sensitized Solar Cells

Anatase TiO 2 nanorods with large specific surface areas and high crystallinity have been synthesized by surfactant‐free hydrothermal treatment of water‐soluble peroxotitanium acid (PTA). X‐ray diffraction and TEM analysis showed that all TiO 2 nanorods derived from PTA in different hydrothermal processes were in the anatase phase, and high aspect ratio TiO 2 nanorods with chain‐shaped structures were formed at 150 °C for 24 h by oriented growth. The nanorods were fabricated as photoanodes for high‐efficiency dye‐sensitized solar cells (DSSCs). DSSCs fabricated from the chain‐shaped TiO 2 nanorods gave a highest short‐circuit current density of 14.8 mA cm −2 and a maximum energy conversion efficiency of 7.28 %, as a result of the presence of far fewer surface defects and grain boundaries than are present in commercial P25 TiO 2 nanoparticles. Electrochemical impedance spectroscopy also confirmed that DSSCs based on the TiO 2 nanorods have enhanced electron transport properties and a long electron lifetime.