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Femtosecond X-ray absorption study of electron localization in photoexcited anatase TiO(2)

Transition metal oxides are among the most promising solar materials, whose properties rely on the generation, transport and trapping of charge carriers (electrons and holes). Identifying the latter’s dynamics at room temperature requires tools that combine elemental and structural sensitivity, with...

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Autores principales: Santomauro, F. G., Lübcke, A., Rittmann, J., Baldini, E., Ferrer, A., Silatani, M., Zimmermann, P., Grübel, S., Johnson, J. A., Mariager, S. O., Beaud, P., Grolimund, D., Borca, C., Ingold, G., Johnson, S.L., Chergui, M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4594303/
https://www.ncbi.nlm.nih.gov/pubmed/26437873
http://dx.doi.org/10.1038/srep14834
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author Santomauro, F. G.
Lübcke, A.
Rittmann, J.
Baldini, E.
Ferrer, A.
Silatani, M.
Zimmermann, P.
Grübel, S.
Johnson, J. A.
Mariager, S. O.
Beaud, P.
Grolimund, D.
Borca, C.
Ingold, G.
Johnson, S.L.
Chergui, M.
author_facet Santomauro, F. G.
Lübcke, A.
Rittmann, J.
Baldini, E.
Ferrer, A.
Silatani, M.
Zimmermann, P.
Grübel, S.
Johnson, J. A.
Mariager, S. O.
Beaud, P.
Grolimund, D.
Borca, C.
Ingold, G.
Johnson, S.L.
Chergui, M.
author_sort Santomauro, F. G.
collection PubMed
description Transition metal oxides are among the most promising solar materials, whose properties rely on the generation, transport and trapping of charge carriers (electrons and holes). Identifying the latter’s dynamics at room temperature requires tools that combine elemental and structural sensitivity, with the atomic scale resolution of time (femtoseconds, fs). Here, we use fs Ti K-edge X-ray absorption spectroscopy (XAS) upon 3.49 eV (355 nm) excitation of aqueous colloidal anatase titanium dioxide nanoparticles to probe the trapping dynamics of photogenerated electrons. We find that their localization at Titanium atoms occurs in <300 fs, forming Ti(3+) centres, in or near the unit cell where the electron is created. We conclude that electron localization is due to its trapping at pentacoordinated sites, mostly present in the surface shell region. The present demonstration of fs hard X-ray absorption capabilities opens the way to a detailed description of the charge carrier dynamics in transition metal oxides.
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spelling pubmed-45943032015-10-13 Femtosecond X-ray absorption study of electron localization in photoexcited anatase TiO(2) Santomauro, F. G. Lübcke, A. Rittmann, J. Baldini, E. Ferrer, A. Silatani, M. Zimmermann, P. Grübel, S. Johnson, J. A. Mariager, S. O. Beaud, P. Grolimund, D. Borca, C. Ingold, G. Johnson, S.L. Chergui, M. Sci Rep Article Transition metal oxides are among the most promising solar materials, whose properties rely on the generation, transport and trapping of charge carriers (electrons and holes). Identifying the latter’s dynamics at room temperature requires tools that combine elemental and structural sensitivity, with the atomic scale resolution of time (femtoseconds, fs). Here, we use fs Ti K-edge X-ray absorption spectroscopy (XAS) upon 3.49 eV (355 nm) excitation of aqueous colloidal anatase titanium dioxide nanoparticles to probe the trapping dynamics of photogenerated electrons. We find that their localization at Titanium atoms occurs in <300 fs, forming Ti(3+) centres, in or near the unit cell where the electron is created. We conclude that electron localization is due to its trapping at pentacoordinated sites, mostly present in the surface shell region. The present demonstration of fs hard X-ray absorption capabilities opens the way to a detailed description of the charge carrier dynamics in transition metal oxides. Nature Publishing Group 2015-10-06 /pmc/articles/PMC4594303/ /pubmed/26437873 http://dx.doi.org/10.1038/srep14834 Text en Copyright © 2015, Macmillan Publishers Limited http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Santomauro, F. G.
Lübcke, A.
Rittmann, J.
Baldini, E.
Ferrer, A.
Silatani, M.
Zimmermann, P.
Grübel, S.
Johnson, J. A.
Mariager, S. O.
Beaud, P.
Grolimund, D.
Borca, C.
Ingold, G.
Johnson, S.L.
Chergui, M.
Femtosecond X-ray absorption study of electron localization in photoexcited anatase TiO(2)
title Femtosecond X-ray absorption study of electron localization in photoexcited anatase TiO(2)
title_full Femtosecond X-ray absorption study of electron localization in photoexcited anatase TiO(2)
title_fullStr Femtosecond X-ray absorption study of electron localization in photoexcited anatase TiO(2)
title_full_unstemmed Femtosecond X-ray absorption study of electron localization in photoexcited anatase TiO(2)
title_short Femtosecond X-ray absorption study of electron localization in photoexcited anatase TiO(2)
title_sort femtosecond x-ray absorption study of electron localization in photoexcited anatase tio(2)
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4594303/
https://www.ncbi.nlm.nih.gov/pubmed/26437873
http://dx.doi.org/10.1038/srep14834
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