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MM: Fachverband Metall- und Materialphysik
MM 35: Topical Session: Hydrogen in Materials: from Storage to Embrittlement VI
MM 35.3: Talk
Wednesday, March 20, 2024, 12:30–12:45, C 130
Computational optimization of nanoalloy hydrogen sensors via composition and geometry — •Pernilla Ekborg-Tanner1, Magnus Rahm1, Victor Rosendal1, Tuomas Rossi2,1, Tomasz Antosiewicz3,1, and Paul Erhart1 — 1Department of Physics, Chalmers University of Technology, Gothenburg, Sweden — 2Department of Applied Physics, Aalto University, Aalto, Finland — 3Faculty of Physics, University of Warsaw, Warsaw, Poland
Plasmonic hydrogen sensing based on nanoalloys could be a solution to the safety issues related to operating hydrogen gas under ambient conditions, which are currently hindering the hydrogen economy. In particular, random arrays of Pd-Au nanodisks have shown great potential as hysteresis-free, reliable hydrogen sensors. While several experimental studies have been conducted, computational studies necessary to efficiently span the rich parameter space in terms of nanodisk geometry and alloy composition are rare. Here, we therefore present a multi-scale modeling approach to hydrogen sensing from atomic scale ab-initio calculations (DFT, TD-DFT) to continuum scale electrodynamic simulations (FDTD) with the purpose of optimizing the sensitivity. In this work, the sensitivity is defined as the shift in peak position with respect to the absorbed hydrogen concentration. The sensitivity is highly tunable via the disk diameter. In addition, it displays a distinct two-regime behavior governed by peak splitting, in contrast to experimental studies. The peak splitting is, in turn, caused by an avoided crossing between the plasmon peak and an interband transition which comes into play at high H content.
Keywords: Hydrogen; Plasmonics; Sensing; Nanoalloy; Multiscale modeling