Controlled synthesis of TiO2-B nanowires and nanoparticles for dye-sensitized solar cells

Controllable synthesis of the TiO2-B nanowires (NWs) and nanoparticles (NPs) had been achieved via a facile hydrothermal route, respectively, only by tuning the solution volume. The dye-sensitized solar cells prototypes had been fabricated using TiO2-B NW and NP electrodes, respectively. The TiO2-B NP cells had higher photocurrent and photoelectrical conversion efficiency than the TiO2-B NW cells though the latter exhibited larger photovoltage compared to the former. The key factors such as the photogenerated electron injection drive force, surface defects and the interfacial charge transfer, which determined the photoelectrical properties, had been systematically researched with the surface photovoltage spectra (SPS) and the electrochemical impedance spectra (EIS). The SPS proved that there was larger photoelectron injection drive force in TiO2-B NP photoelectrode than that in NW photoelectrode. And the electrochemical impedance spectra (EIS) revealed that TiO2-B NP cells had faster interface charge transfer compared to TiO2-B NW cells. Both proved that NP cells had the higher photocurrents.