Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 66: Poster: Nanostructures at Surfaces
O 66.3: Poster
Mittwoch, 20. März 2024, 18:00–20:00, Poster C
Measuring the local surface potential of ionic liquids layers upon charge deposition — •Mirco Wendt1,2, Regina Lange2, Jens Berdermann1, Ingo Barke2, and Sylvia Speller2 — 1Institute for Solar-Terrestrial Physics, German Aerospace Center (DLR), Kalkhorstweg 53, 17235 Neustrelitz — 2Institute of Physics, University of Rostock, Albert-Einstein-Str. 25 18059 Rostock
The interaction of ionic liquids (IL) with surfaces at different potentials is extensively studied with respect to their potential application in double layer capacitors[1,2]. The surface potential of the liquid itself, however, is rarely investigated[3], although it was shown that electrostatic screening in IL does not adhere to well established models for low concentration electrolytes[4]. We show how the local surface potential of 1-Butyl-1-methyl-pyrrolidinium- dicyanamide (BMP DCA) can be measured in ultra-high vacuum, using a q-Plus-Sensor in a Kelvin-Probe-like configuration. We address implications and assets of this approach and discuss its application to BMP DCA thin films on floating gold islands on top of glass. To modify the native surface potential, patches of this film were exposed to the electron beam of a scanning electron microscope and show both temporary and permanent contrast differences upon prolonged exposure. Studying the local surface potential of such patches and its evolution should allow for a better understanding of mechanisms involved.
[1] Thangavel, et al., J. Power Sources 2018 [2] Han, et al., Adv. Mater. Interfaces 2020 [3] Zhang, et al., Acta Phys. Chim. Sin. 2016 [4] Gebbie, et al., Proc. Natl. Acad. Sci. 2013