Application of TiO2 Fusiform Nanorods for Dye-Sensitized Solar Cells with Significantly Improved Efficiency

Anatase TiO2 fusiform nanorods with diameters 20-80 nm and lengths 200-400 nm are synthesized by a two-step hydrothermal method, and the effects of the obtained TiO2 nanorod content in a P25-based electrode on the performances of dye-sensitized solar cell were investigated by using photocurrent-voltage, open-circuit voltage decay and electrochemical impedance spectroscopy measurements. The results show that those fiisiform TiO2 nanorods in the P25-based electrode not only provide a straight path for the electron transport but also function as scattering particles to increase light harvesting efficiency of the solar cell, and the optimal conversion efficiency of 4.68% is obtained from a solar cell fabricated with a P25-based electrode containing 10 wt % nanorods, with a 66.5% improvement in the efficiency with lower resistance and longer electron lifetimes as compared to the bare P25-based solar cell. This should be attributed to the reduced charge recombination and the sufficient scattering effect of the nanorods in the film electrode.