Hierarchical Nanorod/Nanoflower TiO2 Photoanode for Natural Dye-Sensitized Solar Cells

Different morphologies of rutile TiO2 from microsphere, nanowire, and hierarchical nanorod/nanoflowers are successfully fabricated via hydrothermal reactions of titanium tetraisopropoxide and hydrochloric acid. Dye-sensitized solar cells (DSSCs) were assembled using natural gardenia yellow dyes extracted from Gardenia Jasminoide Ellis as a sensitizer. In this work, we studied the adsorption characteristics for harvesting sunlight and the electrochemical behavior for electron transfer in gardenia yellow DSSC using different morphologies TiO2 photoanode. The DSSC based on the hierarchical rutile TiO2 nanorod/nanoflower photoelectrode shows an energy conversion efficiency of 0.85% accompanying a short-circuit current density of 2.11 mA cm(-2), an open-circuit voltage of 0.63 V and fill factor of 0.64, which is higher than that of microsphere (0.71%), nanowires (0.61%). The enhancement of short-circuit current density and energy conversion efficiency for the hierarchical nanorod/nanoflower-based DSSC compared to other structures is mainly contributed to the larger dye loading, higher light scattering ability, and faster electron transport.