Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 61: Plasmonics and Nanooptics 2

O 61.6: Vortrag

Donnerstag, 8. September 2022, 12:00–12:15, H2

Investigation of chemical interface damping on electrochemically functionalized flat gold and nanoporous gold surfaces — •Maurice Pfeiffer¹, Xinyan Wu¹, Alexander Petrov^1,2, and Manfred Eich^1,2 — ¹Institute of Optical and Electronic Materials, Hamburg University of Technology, Germany — ²Institute of Photoelectrochemistry, Helmholtz-Zentrum Hereon, Geesthacht, Germany

The chemical interface damping (CID) effect occurs at metal surfaces when applying surface modifications, such as oxidation. It results in an increase of the electron collision frequency of the metal, thus altering its optical properties. Previous research showed that this effect may also enhance the efficiency of photocatalytic water splitting by visible light [1]. We investigate the CID effect on flat gold as well as nanoporous gold samples with the latter having the advantage of a very high surface to volume ratio, making surface effects (like CID) more pronounced. Our experimental setup consists of a spectroscopic ellipsometer to investigate the optical properties. This device is equipped with an electrochemical cell in which we can reversibly oxidize the sample surface, allowing an in-situ study of the CID effect. Previous research investigated the CID effect on gold nanoparticles and observed an increase of the damping rate at the plasmon resonance [2]. Our results on flat gold reveal a similar increase of the damping, but additionally enable the investigation of broadband properties from which we expect further insights on the nature of the damping mechanism.

[1] Graf et al., ACS Nano 2021, 15, 2, 3188-3200 [2] Foerster et al., Nano Lett. 2020, 20, 5, 3338-3343