Berlin 2024 – scientific programme

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O: Fachverband Oberflächenphysik

O 32: Poster: Solid-Liquid Interfaces

O 32.5: Poster

Tuesday, March 19, 2024, 18:00–20:00, Poster C

Influence of Cholic Acid and 1-Methylbenzimidazole on Cell Performance in Water-Based Dye-Sensitized Solar Cells — •Leon Rosenbecker, Daniel Holzhacker, and Derck Schlettwein — Institut für Angewandte Physik, Justus-Liebig-Universität Gießen

Dye-Sensitized Solar Cells (DSSCs) present an environmentally friendly low-cost photovoltaic concept, interesting under conditions of low light intensity and, in particular, for indoor applications. However, commonly used materials such as platinum at the counter electrode, acetonitrile as the solvent, and cobalt complexes as the redox mediator can be considered problematic. In this work, DSSCs with aqueous solutions of readily available 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as the redox mediator were prepared. To suppress undesired recombination, we studied cholic acid (CA) as a co-adsorbate, 1-methylbenzimidazole (MBI) as an electrolyte additive, or a combination of both. CA as a co-adsorbate improved both the short-circuit current density (jsc) and fill factor (FF) while not affecting the open-circuit voltage (Voc) up to a concentration of 7.5 mM in the dye bath. In case MBI was used as the additive in the electrolyte, also the Voc was improved, while jsc and FF were found to be higher than for CA. Increasing the MBI concentration from 0.1 M up to 0.4 M steadily increased the performance. A combination of both additives further increased the short-circuit current density while not sacrificing on the other cell characteristics.

Keywords: dye-sensitized solar cells; recombination; adsorption; electrolyte