786759.fig.0011a
(a)
786759.fig.0011b
(b)
Figure 11: (a) Absorbance changes (at 780 nm) of a transparent nanocrystalline TiO2 film recorded during a cathodic potential sweep in a deaerated LiClO4 (0.1 M) solution with adjusted pH. The arrows indicate potentials at which the values of quasi-Fermi level were read off. (b) pH dependence of quasi-Fermi levels of a transparent nanocrystalline TiO2 film. Measurements were performed outside the neutral pH range in order to avoid pH fluctuations due to reduction of protons [206].