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O: Fachverband Oberflächenphysik

O 76: Plasmonics and Nanooptics VII: Applications and Other Aspects

O 76.8: Vortrag

Mittwoch, 22. März 2017, 16:45–17:00, TRE Ma

Watching hydride formation in single plasmonic magnesium nanoparticles — •Florian Sterl, Heiko Linnenbank, Nikolai Strohfeldt, and Harald Giessen — 4th Physics Institute and Research Center SCoPE, University of Stuttgart, Germany

Magnesium (Mg) has recently demonstrated its potential for active plasmonics in the visible wavelength range via the absorption of hydrogen. We have shown that this can be achieved by using Mg nanoantennas with a catalytic palladium (Pd) capping layer. Upon hydrogenation, Mg forms non-metallic magnesium hydride (MgH₂). In this system, the plasmonic resonance can be switched off and back on via exposure to hydrogen and oxygen gas, with switching times on the order of tens of seconds. On one hand, this leads to potential applications such as tunable plasmonic displays. On the other hand, the system can be used to investigate the hydrogenation of Mg.

MgH₂ is considered a promising candidate for solid-state hydrogen storage, owing to its high hydrogen content of up to 7.6 wt%, and can also be considered a model system for other energy storage materials. We aim for a better understanding and characterization of the hydrogen diffusion in Mg at the nanoscale, using different techniques: We investigate the time dynamics of the Mg-MgH₂ phase transition using the optical far field of Mg/Pd nanoantennas, and probe the optical near field of individual Mg nanostructures to observe the evolution of hydrogenated domains during this transition. We furthermore address the mechanical deformation due to the hydrogen-induced expansion of the Mg crystal lattice.