Journal Article

FZJ-2022-02630

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Interpretation of Mott–Schottky plots of photoanodes for water splitting

Ravishankar, S. (Corresponding author)FZJ* ; Bisquert, J. ; Kirchartz, T.FZJ*

2022
RSC Cambridge

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Please use a persistent id in citations: http://hdl.handle.net/2128/32050  doi:10.1039/D1SC06401K

Abstract: A large body of literature reports that both bismuth vanadate and haematite photoanodes are semiconductors with an extremely high doping density between 10^18-10^21 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 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.

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Contributing Institute(s):

1. Photovoltaik (IEK-5)

Research Program(s):

1. 1215 - Simulations, Theory, Optics, and Analytics (STOA) (POF4-121) (POF4-121)

Appears in the scientific report 2022

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Database coverage:
; ; ; ; Chemical Reactions ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; Essential Science Indicators ; IF >= 5 ; Index Chemicus ; JCR ; National-Konsortium ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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