Dynamics of photogenerated holes in nanocrystalline alpha-Fe2O3 electrodes for water oxidation probed by transient absorption spectroscopy

Transient absorption spectroscopy on the mu s-s time scale is used to monitor the yield and decay dynamics of photogenerated holes in nanocrystalline hematite photoanodes. In the absence of a positive applied bias, these holes are observed to undergo rapid electron-hole recombination. The application of a positive bias results in the generation of long-lived (3 +/- 1 s lifetime) photoholes.