Uppachai, P, Harnchana, V, Pimanpang, S et al. (3 more authors) (2014) A substoichiometric tungsten oxide catalyst provides a sustainable and efficient counter electrode for dye-sensitized solar cells. Electrochimica Acta, 145. 27 - 33. ISSN 0013-4686
Abstract
Development of Pt-free catalyst materials for the counter electrode (CE) in dye-sensitized solar cells (DSSCs) has been regarded as one of the crucial steps to improving energy conversion efficiency and cost effectiveness of DSSCs. In this work, low cost tungsten oxide (WO3-x) counter electrodes, prepared by annealing tungsten metal sheets under an Ar and low O2atmosphere, exhibited high catalytic activity and energy conversion efficiency. The highest efficiency achieved here for DSSCs with WO3-xcounter electrodes, was 5.25%, obtained from a 500 °C annealed tungsten sheet. TEM and XPS analysis suggested the formation of sub-stoichiometric tungsten oxide layer (∼WO2.6) with the presence of W6+, W5+and W4+oxidation states at the tungsten metal surface after the 500 °C annealing. Only W6+and W5+oxidation states were detected after a 600 °C annealing indicating the formation of a more stoichiometric tungsten oxide layer (∼WO2.8) and resulting in a drop in efficiency of the DSSC. We suggest that mixed valence tungsten states account for the excellent catalytic activity and good electrical conductivity as evidenced by the highest cyclic voltammetry response of 0.76 mA/cm2and the lowest impedance value of 44.33 Ω, respectively.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2014. Elsevier. Uploaded in accordance with the publisher's self-archiving policy. NOTICE: this is the author’s version of a work that was accepted for publication in Electrochimica Acta. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Electrochimica Acta, 145,(2014) DOI:10.1016/j.electacta.2014.08.096 |
Keywords: | Counter electrode; dye-sensitized solar cell; substoichiometric tungsten oxide |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) > Institute for Materials Research (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 27 Nov 2014 09:35 |
Last Modified: | 20 Apr 2015 12:58 |
Published Version: | http://dx.doi.org/10.1016/j.electacta.2014.08.096 |
Status: | Published |
Publisher: | Elsevier Ltd |
Refereed: | Yes |
Identification Number: | 10.1016/j.electacta.2014.08.096 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:81341 |