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Analysis of the interfacial characteristics of BiVO4/metal oxide heterostructures and its implication on their junction properties

Hermans, Yannick and Murcia-López, Sebastián and Klein, Andreas and Morante, Joan R. and van de Krol, Roel and Andreu, Teresa and Toupance, Thierry and Jaegermann, W. (2019):
Analysis of the interfacial characteristics of BiVO4/metal oxide heterostructures and its implication on their junction properties.
In: Physical Chemistry Chemical Physics, Royal Society of Chemistry, pp. 5086-5096, 21, (9), ISSN 1463-9076,
DOI: 10.1039/C8CP07483F,
[Online-Edition: https://doi.org/10.1039/C8CP07483F],
[Article]

Abstract

The formation of heterostructures has proven to be a viable way to achieve high photoelectrochemical water splitting efficiencies with BiVO4 based photoanodes. Especially, cobalt and nickel based oxides are suitable low cost contact materials. However, the exact role of these contact materials is not yet completely understood because of the difficulty to individually quantify the effects of surface passivation, charge carrier separation and catalysis on the efficiency of a heterostructure. In this study, we used photoelectron spectroscopy in combination with in situ thin film deposition to obtain direct information on the interface structure between polycrystalline BiVO4 and NiO, CoOx and Sn-doped In2O3 (ITO). Strong upwards band bending was observed for the BiVO4/NiO and BiVO4/CoOx interfaces without observing chemical changes in BiVO4, while limited band bending and reduction of Bi and V was observed while forming the BiVO4/ITO interface. Thus, the tunability of the Fermi level position within BiVO4 seems to be limited to a certain range. The feasibility of high upwards band bending through junctions with high work function (WF) compounds demonstrate that nickel oxide and cobalt oxide are able to enhance the charge carrier separation in BiVO4. Similar studies could help to identify whether new photoelectrode materials and their heterostructures would be suitable for photoelectrochemical water splitting.

Item Type: Article
Erschienen: 2019
Creators: Hermans, Yannick and Murcia-López, Sebastián and Klein, Andreas and Morante, Joan R. and van de Krol, Roel and Andreu, Teresa and Toupance, Thierry and Jaegermann, W.
Title: Analysis of the interfacial characteristics of BiVO4/metal oxide heterostructures and its implication on their junction properties
Language: English
Abstract:

The formation of heterostructures has proven to be a viable way to achieve high photoelectrochemical water splitting efficiencies with BiVO4 based photoanodes. Especially, cobalt and nickel based oxides are suitable low cost contact materials. However, the exact role of these contact materials is not yet completely understood because of the difficulty to individually quantify the effects of surface passivation, charge carrier separation and catalysis on the efficiency of a heterostructure. In this study, we used photoelectron spectroscopy in combination with in situ thin film deposition to obtain direct information on the interface structure between polycrystalline BiVO4 and NiO, CoOx and Sn-doped In2O3 (ITO). Strong upwards band bending was observed for the BiVO4/NiO and BiVO4/CoOx interfaces without observing chemical changes in BiVO4, while limited band bending and reduction of Bi and V was observed while forming the BiVO4/ITO interface. Thus, the tunability of the Fermi level position within BiVO4 seems to be limited to a certain range. The feasibility of high upwards band bending through junctions with high work function (WF) compounds demonstrate that nickel oxide and cobalt oxide are able to enhance the charge carrier separation in BiVO4. Similar studies could help to identify whether new photoelectrode materials and their heterostructures would be suitable for photoelectrochemical water splitting.

Journal or Publication Title: Physical Chemistry Chemical Physics
Volume: 21
Number: 9
Publisher: Royal Society of Chemistry
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Electronic Structure of Materials (ESM)
11 Department of Materials and Earth Sciences > Material Science > Surface Science
Date Deposited: 31 Jan 2019 15:28
DOI: 10.1039/C8CP07483F
Official URL: https://doi.org/10.1039/C8CP07483F
Funders: This work was carried out in the framework of EJD-FunMat and has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 641640., In addition, the authors from IREC thank Generalitat de Catalunya for financial support through the CERCA Program and M2E (2017SGR1246)., The authors were supported by by the European Regional Development Funds (ERDF, FEDER) and MINECO project ENE2017-85087-C3-2-R., SM-L thanks European Union's Horizon 2020 and the Agency for Business Competitiveness of the Government of Catalonia for funding under the Marie Sklodowska-Curie grant agreement no. 712939 (TECNIOspring PLUS).
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