Effect of molecular filtering and electrolyte composition on the spatial variation in performance of dye solar cells

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© 2012 Elsevier BV. This is the post print version of the following article: Miettunen, Kati & Asghar, Imran & Mastroianni, Simone & Halme, Janne & Barnes, Piers R.F. & Rikkinen, Emma & O’Regan, Brian C. & Lund, Peter. 2012. Effect of molecular filtering and electrolyte composition on the spatial variation in performance of dye solar cells. Journal of Electroanalytical Chemistry. Volume 664. 63-72. ISSN 1572-6657 (printed). DOI: 10.1016/j.jelechem.2011.10.012., which has been published in final form at http://www.sciencedirect.com/science/article/pii/S1572665711005303. This post-print is published with permission from Elsevier under CC BY-NC-ND 4.0 license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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Journal Title

Journal ISSN

Volume Title

School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2012

Major/Subject

Mcode

Degree programme

Language

en

Pages

63-72

Series

Journal of Electroanalytical Chemistry, Volume 664

Abstract

It is demonstrated that the molecular filtering effect of TiO2 has a significant influence on dye solar cell (DSC) performance. As electrolyte is injected to a DSC, some of the electrolyte components adsorb to the surface TiO2 (here 4-tert-butylpyridine and 1-methyl-benzimidazole) and accumulate near the electrolyte filling hole resulting in varying electrolyte composition and performance across the cell. The spatial performance distribution was investigated with a new method, the segment cell method. Not only is the segmented cell method simple and cheap when compared to the only other method for examining spatial variation (photocurrent mapping), it also has the major advantage of allowing the spatial variation in all other operating parameters to be assessed. Here the molecular filtering effect was to influence the cell performance in case of all the five studied electrolytes causing up to 35% losses in efficiency. Raman spectra indicated that the loss in photocurrent in the electrolyte filling was in correlation with the loss of thiocyanate ligands suggesting that dye regeneration may also be a significant factor in addition to electron injection in some of the cells. There were also shifts in the absorption spectra the photoelectrodes which further supported changes in the thiocyanate ligands. Besides absorption changes, there were additional shifts in the IPCE spectra which may relate to deprotonation of the dye. The efficiency losses were reduced to ∼10% with contemporary electrolyte compositions.

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Keywords

Dye-sensitized, Up-scaling, Spatial distribution, Electrolyte filling

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Citation

Miettunen, Kati & Asghar, Imran & Mastroianni, Simone & Halme, Janne & Barnes, Piers R.F. & Rikkinen, Emma & O’Regan, Brian C. & Lund, Peter. 2012. Effect of molecular filtering and electrolyte composition on the spatial variation in performance of dye solar cells. Journal of Electroanalytical Chemistry. Volume 664. 63-72. ISSN 1572-6657 (printed). DOI: 10.1016/j.jelechem.2011.10.012.