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O: Fachverband Oberflächenphysik
O 18: Solid-Liquid Interfaces I: Structure and Spectroscopy
O 18.11: Talk
Monday, March 18, 2024, 17:30–17:45, H 1012
Impedance Spectroscopy with Microscopic Reference Electrodes as a Technique to Study Electrode Kinetics in Dye-Sensitized Solar Cells — •Daniel Holzhacker and Derck Schlettwein — Institut für Angewandte Physik, Justus-Liebig-Universität Gießen
A detailed impedance analysis of dye-sensitized solar cells (DSSC) is essential to precisely optimize performance-limiting steps in these cells. Two-electrode impedance measurements as typically used, however, often do not allow a separate analysis of charge transfer reactions at different electrodes that occur with similar time constants. The use of a microscopic quasi-reference electrode (µ RE) offers the possibility to separately record impedance spectra of the photoanode (WE) and the counter electrode (CE) of a DSSC under operating conditions in one experiment. In three-electrode experiments, the potential was modulated between the µ RE and WE. The respective impedance (ZWE) and, simultaneously, the impedance between µ RE and CE (ZCE) were recorded and the overall cell impedance Z calculated. The latter was identical to Z determined in a two-electrode measurement, proving the validity of the experimental approach. Thus, one experiment yielded spectra for the full cell and both respective half-cells, which allowed to simultaneously study the interactions of novel redox mediators with photoanodes and counter electrode materials in detail.
Keywords: impedance; dye-sensitized solar cells; electrolyte; charge transfer