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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 (?-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-?s 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.

SUBMITTER: Pendlebury SR

PROVIDER: S-EPMC4210134 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature

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Ultrafast charge carrier recombination and trapping in hematite photoanodes under applied bias.

Pendlebury Stephanie R SR Wang Xiuli X Le Formal Florian F Cornuz Maurin M Kafizas Andreas A Kafizas Andreas A Tilley S David SD Grätzel Michael M Durrant James R JR

Journal of the American Chemical Society 20140702 28

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 tim ...[more]

PMID: 24950057

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