title: Ultrafast charge carrier recombination and trapping in hematite photoanodes under applied bias.
abstract: Transient absorption spectroscopy on subpicosecond to second time scales is used to investigate photogenerated charge carrier recombination in Si-doped nanostructured hematite (α-Fe2O3) photoanodes as a function of applied bias. For unbiased hematite, this recombination exhibits a 50% decay time of ~6 ps, ~10(3) times faster than that of TiO2 under comparable conditions. Anodic bias significantly retards hematite recombination dynamics, and causes the appearance of electron trapping on ps-μs time scales. These ultrafast recombination dynamics, their retardation by applied bias, and the associated electron trapping are discussed in terms of their implications for efficient water oxidation.
authors.affiliation: Department of Chemistry, Imperial College London, South Kensington Campus , London, SW7 2AZ, United Kingdom.
authors.forename: Stephanie R
authors.initials: SR
authors.lastname: Pendlebury
authors.forename: Xiuli
authors.initials: X
authors.lastname: Wang
authors.forename: Florian
authors.initials: F
authors.lastname: Le Formal
authors.forename: Maurin
authors.initials: M
authors.lastname: Cornuz
authors.forename: Andreas
authors.initials: A
authors.lastname: Kafizas
authors.forename: S David
authors.initials: SD
authors.lastname: Tilley
authors.forename: Michael
authors.initials: M
authors.lastname: Grätzel
authors.forename: James R
authors.initials: JR
authors.lastname: Durrant