Impact of Oxygen Vacancy Occupancy on Charge Carrier Dynamics in BiVO4 Photoanodes
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Show full item recordcomunitat-uji-handle:10234/9
comunitat-uji-handle2:10234/2507
comunitat-uji-handle3:10234/6973
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INVESTIGACIONMetadata
Title
Impact of Oxygen Vacancy Occupancy on Charge Carrier Dynamics in BiVO4 PhotoanodesAuthor (s)
Date
2019-11-27Publisher
American Chemical SocietyISSN
0002-7863Bibliographic citation
SELIM, Shababa, et al. Impact of oxygen vacancy occupancy on charge carrier dynamics in BiVO4 photoanodes. Journal of the American Chemical Society, 2019, vol. 141, no 47, p. 18791-18798.Type
info:eu-repo/semantics/articlePublisher version
https://pubs.acs.org/doi/abs/10.1021/jacs.9b09056Version
info:eu-repo/semantics/acceptedVersionSubject
Abstract
Oxygen vacancies are ubiquitous in metal oxides and critical to performance, yet the impact of these states upon charge carrier dynamics important for photoelectrochemical and photocatalytic applications remains ... [+]
Oxygen vacancies are ubiquitous in metal oxides and critical to performance, yet the impact of these states upon charge carrier dynamics important for photoelectrochemical and photocatalytic applications remains contentious and poorly understood. A key challenge is the unambiguous identification of spectroscopic fingerprints which can be used to track their function. Herein, we employ five complementary techniques to modulate the electronic occupancy of states associated with oxygen vacancies in situ in BiVO4 photoanodes, allowing us to identify a spectral signature for the ionization of these states. We obtain an activation energy of ∼0.2 eV for this ionization process, with thermally activated electron detrapping from these states determining the kinetics of electron extraction, consistent with improved photoelectrochemical performance at higher temperatures. Bulk, un-ionized states, however, function as deep hole traps, with such trapped holes energetically unable to drive water oxidation. These observations help address recent controversies in the literature regarding oxygen vacancy function, providing new insights into their impact upon photoelectrochemical performance. [-]
Is part of
J. Am. Chem. Soc. 2019, 141, 47, 18791–18798Investigation project
(project Intersolar 291482), (RSG\R1\180434), (658271), (Project ENE2017-85087-C3-1-R), (Grant Agreement No. 639750)Rights
Copyright © 2019 American Chemical Society
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info:eu-repo/semantics/openAccess
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info:eu-repo/semantics/openAccess
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