Abstract
Oriented, single-crystal TiO2 nanorod arrays (NRAs) were synthesized for photoelectrochemical (PEC) water-splitting by a facile hydrothermal route. It was observed that a 500°C annealing process facilitated enhancing the PEC activity of TiO2 NRAs, in agreement with our previous reports on NRA-related solar cells. Further, electrochemical impedance measurements were employed to investigate the underlying mechanism. Compared with pristine TiO2 NRAs, the 500°C sintered samples showed a positive flat-band shifting of ∼0.12 V as well as a suppression of the donor density. Thus, suggesting that the enhanced PEC performance might be attributed to the widening of depletion layer regions due to the reduction of crystal defects after sintering. The mechanism was also expanded to explain why the dye-sensitized solar cells made with sintered TiO2 NRAs exhibited an 11-times higher power conversion efficiency than those consisting of pristine arrays.
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Zhang, S., Gu, X., Zhao, Y. et al. Enhanced Photoelectrochemical Performance of TiO2 Nanorod Arrays by a 500°C Annealing in Air: Insights into the Mechanism. J. Electron. Mater. 45, 648–653 (2016). https://doi.org/10.1007/s11664-015-4166-x
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DOI: https://doi.org/10.1007/s11664-015-4166-x