Imperial College London
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DrAndreasKafizas

Faculty of Natural Sciences, Department of Chemistry

Senior Lecturer
 
 
 
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Contact

 

+44 (0)20 7594 6752a.kafizas Website

 
 
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Location

 

301GMolecular Sciences Research HubWhite City Campus

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Summary

 

Publications

Citation

BibTex format

@article{Selim:2019:10.1021/jacs.9b09056,
author = {Selim, S and Pastor, E and García-Tecedor, M and Morris, MR and Francas, L and Sachs, M and Moss, B and Corby, S and Mesa, CA and Gimenez, S and Kafizas, A and Bakulin, AA and Durrant, JR},
doi = {10.1021/jacs.9b09056},
journal = {Journal of the American Chemical Society},
pages = {18791--18798},
title = {Impact of oxygen vacancy occupancy on charge carrier dynamics in BiVO4 photoanodes},
url = {http://dx.doi.org/10.1021/jacs.9b09056},
volume = {141},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - 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 ionisation of these states. We obtain an activation energy of  0.2 eV for this ionisation process, with thermally activated electron de-trapping from these states determining the kinetics of electron extraction, consistent with improved photoelectrochemical performance at higher temperatures. Bulk, un-ionised states however, function as deep hole traps, with such trapped holes being energetically unable to drive water oxidation. These observations help address recent controversies in the literature over oxygen vacancy function, providing new insights into their impact upon photoelectrochemical performance.
AU  - Selim,S
AU  - Pastor,E
AU  - García-Tecedor,M
AU  - Morris,MR
AU  - Francas,L
AU  - Sachs,M
AU  - Moss,B
AU  - Corby,S
AU  - Mesa,CA
AU  - Gimenez,S
AU  - Kafizas,A
AU  - Bakulin,AA
AU  - Durrant,JR
DO  - 10.1021/jacs.9b09056
EP  - 18798
PY  - 2019///
SN  - 0002-7863
SP  - 18791
TI  - Impact of oxygen vacancy occupancy on charge carrier dynamics in BiVO4 photoanodes
T2  - Journal of the American Chemical Society
UR  - http://dx.doi.org/10.1021/jacs.9b09056
UR  - https://www.ncbi.nlm.nih.gov/pubmed/31663329
UR  - https://pubs.acs.org/doi/abs/10.1021/jacs.9b09056
UR  - http://hdl.handle.net/10044/1/74427
VL  - 141
ER  -
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