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HL: Fachverband Halbleiterphysik

HL 61: Plasmonics and Nanooptics VII: Applications and Other Aspects

HL 61.9: Vortrag

Mittwoch, 22. März 2017, 17:00–17:15, TRE Ma

Palladium Nanopatches - Size-dependent Hydrogen Kinetics — •Nikolai Strohfeldt¹, Florian Sterl¹, Ronald Griessen², and Harald Giessen¹ — ¹4th Physics Institute and Research Center SCoPE, University of Stuttgart, Stuttgart, Germany — ²Faculty of Sciences, Division of Physics and Astronomy, VU University, Amsterdam, The Netherlands

Nanoparticles exhibit many potentially interesting properties that are relevant for key applications such as storage of energy in batteries or data in non-volatile memories. Especially the storage of hydrogen in nanomaterials has stimulated the development of powerful new investigation methods. Electron-beam lithography makes it possible to create essentially monodisperse ensembles of particles, which can conveniently be studied with optical and plasmonic methods. In nanoparticles, H desorption occurs fully coherently only for small crystalline nanocubes (typically smaller than 50 nm) at temperatures sufficiently close to the critical temperature. For larger particles, it is partially incoherent, where dilute α-PdH_x and high concentration β-PdH_x phases coexist. In polycrystalline particles, larger than 200 nm, the H absorption occurs at much lower pressures than in nanocubes. With a newly developed localized surface plasmon resonance method we succeeded in determining the size dependence of the hydrogen induced in-plane and out-of-plane expansion. With increasing size the in-plane expansion of these particles is increasingly hampered. The knowledge gathered with Pd-H nanoparticles is at the basis of recent developments of active plasmonic elements based on the Y-H and Mg-H systems.