Interpretation of Mott-Schottky plots of photoanodes for water splitting
comunitat-uji-handle:10234/9
comunitat-uji-handle2:10234/160292
comunitat-uji-handle3:10234/160293
comunitat-uji-handle4:
INVESTIGACIONMetadata
Title
Interpretation of Mott-Schottky plots of photoanodes for water splittingDate
2022-03-31Publisher
The Royal Society of ChemistryBibliographic citation
RAVISHANKAR, Sandheep; BISQUERT, Juan; KIRCHARTZ, Thomas. Interpretation of Mott–Schottky plots of photoanodes for water splitting. Chemical Science, 2022, vol. 13, no 17, p. 4828-4837.Type
info:eu-repo/semantics/articleVersion
info:eu-repo/semantics/publishedVersionSubject
Abstract
A large body of literature reports that both bismuth vanadate and haematite photoanodes are semiconductors with an extremely high doping density between 1018 and 1021 cm−3. Such values are obtained from Mott–Schottky ... [+]
A large body of literature reports that both bismuth vanadate and haematite photoanodes are semiconductors with an extremely high doping density between 1018 and 1021 cm−3. Such values are obtained from Mott–Schottky plots by assuming that the measured capacitance is dominated by the capacitance of the depletion layer formed by the doping density within the photoanode. In this work, we show that such an assumption is erroneous in many cases because the injection of electrons from the collecting contact creates a ubiquitous capacitance step that is very difficult to distinguish from that of the depletion layer. Based on this reasoning, we derive an analytical resolution limit that is independent of the assumed active area and surface roughness of the photoanode, below which doping densities cannot be measured in a capacitance measurement. We find that the reported doping densities in the literature lie very close to this value and therefore conclude that there is no credible evidence from capacitance measurements that confirms that bismuth vanadate and haematite photoanodes contain high doping densities. [-]
Is part of
Chem. Sci., 2022,13Funder Name
German Research Foundation (DFG), Walter-Benjamin fellowship | Helmholtz Association
Project code
462572437 | POF-IV program | 491111487
Rights
© 2022 The Author(s). Published by the Royal Society of Chemistry
info:eu-repo/semantics/openAccess
info:eu-repo/semantics/openAccess
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