Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 87: Plasmonics and Nanooptics: Light-Matter Interaction, Spectroscopy I
O 87.7: Vortrag
Donnerstag, 20. März 2025, 16:30–16:45, H4
Photoheating nanoscale Pd to temperatures exceeding attached Au nanoparticle antennas — Felix Stete1, Shivani Kesarwani2, Charlotte Ruhmlieb2, Florian Schulz2, Marc Herzog1, Holger Lange1,2, and •Matias Bargheer1,3 — 1Universität Potsdam — 2Universität Hamburg — 3Helmholtz-Zentrum Berlin
In the non-equilibrium following optical excitation, energy transfer processes at the nanoscale can exhibit extraordinary and surprising phenomena such as heat transport without heating and dominant phonon heat transport in the nobel metal gold. Here we present transient absorption experiments on a systematic and well-characterized series of gold nanoparticles with a Pd satellite shell. Modeling the fluence dependence of the entire series of hybrid structures with a fixed set of thermophysical parameters shows that we can create hybrid nano-photo-catalysts that concentrate light energy into the catalytically active Pd. We can make a few Pd satellites efficiently collect nearly all photothermal energy deposited by plasmonically enhanced absorption in gold and heat up the Pd by 180 K while the gold core remains cold. Consequently, highly active catalytic sites emerge which can enhance light driven molecular transformations. The tailoring and modeling of such unexpected nanoscale energy transfer phenomena is backed up by ultrafast x-ray diffraction experiments that provide a material-specific direct measure of the crystal lattice response to energy in phonons and electrons of each material in heterostructures and nanocomposites.
Keywords: electron-phonon interaction; heat transport; ultrafast spectroscopy; Gold; plansmon