Effect of growth time on morphology and photoelectrochemical performance of TiO2 nanorod arrays grown on transparent conducting substrates

TiO 2 nanorod arrays (NRAs) were synthesized directly on the fluorine tin oxide (FTO) coated glass substrates by a facile hydrothermal route. The effects of growth time on the photoelectrochemical (PEC) properties of TiO 2 NRAs are investigated. The samples synthesized for 4 h exhibit a photocurrent intensity of 0.37 mA/cm 2 at the irradiation of Xe lamp and a bias of 0 V. As the growth time increases, the thickness and order degree of the NRAs are enhanced, but the photocurrent is reduced a lot. It might be associated with the hindering of a high background electron density in NRs due to the long-time hydrothermal reaction in acid environment. Moreover, the decline behavior is observed, which is attributed to the poor charge separation capacity of TiO 2 array electrodes and could be suppressed efficiently by applying a suitable positive bias.