Regensburg 2007 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 5: Photovoltaic
HL 5.5: Vortrag
Montag, 26. März 2007, 12:00–12:15, H14
Tuning the photovoltage of dye-sensitized solar cells based on electrodeposited ZnO — •Torsten Oekermann1, Laurence Peter2, and Tsukasa Yoshida3 — 1Institute of Physical Chemistry and Electrochemistry, Leibniz Universität Hannover, Callinstrasse 3-3A, 30167 Hannover, Germany — 2Department of Chemistry, University of Bath, Bath BA2 7AY, United Kingdom — 3Graduate School of Engineering, Gifu University, Yanagido 1-1, Gifu 501-1193, Japan
Nanoporous, fully crystalline ZnO films can be prepared by cathodic electrodeposition from aqueous solutions of Zn salts under the influence of structure-directing agents such as surfactants. Dye-sensitized solar cells (DSSC) based on such films have emerged as a possible alternative for nanocrystalline TiO2-based DSSC due to the very high porosity and good electron transport properties of the films.[1] In this study, we have investigated the influence of the sensitizer dye molecules on the photovoltage of the ZnO-based DSSC. Impedance measurements show that the adsorbed dye molecules lead to a shift of the flatband potential of the ZnO. Electron pushing or withdrawing effects of the dye molecules and protonation or deprotonation of the ZnO surface are discussed as possible explanations. The shifts in the flatband potential partly explain the differences in the photovoltages caused by different dyes, however, differences in the electron injection efficiency and the blocking of electron back reaction by the dye molecules have to be taken into account, too, for a complete description.
[1] Oekermann, T.; Yoshida, T.; Minoura, H.; Wijayantha, K. G. U.; Peter, L.M. J. Phys. Chem. B 2004, 108, 8364.