Regensburg 2019 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 50: Plasmonics & Nanooptics III: STM and Time-Resolved Methods (joint session O/CPP)
O 50.10: Vortrag
Mittwoch, 3. April 2019, 12:45–13:00, H8
Direct optical excitation of dark plasmons for hot electron generation. — •Dominik Höing1, Niclas Müller2, Florian Schulz1, Stephanie Reich2, and Holger Lange1 — 1Institut für Physikalische Chemie, Universität Hamburg, Sedanstraße 19, VG1-045, 20146 Hamburg — 2Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, Raum 1.2.42, 14195 Berlin
Plasmonic gold nanoparticles (AuNP) are of great interest because of their ability to generate hot charge carriers, which can play a key role in photoinduced catalysis [1]. Previous studies have shown that the generation of hot carriers depends on whether or not the photon energy is larger than the threshold for interband transitions while exciting at the plasmon resonance seems to have a low effect [2]. A possible explanation might be a significant contribution of radiative energy losses during the plasmon decay. Dark plasmon modes, which can be observed in AuNP multilayers, do not couple to the far field and might allow to reduce such losses [3]. An experimental access to the efficiency of hot carrier generation is transient absorption spectroscopy. It has proven to be a reliable method as it allows assessing the initial temperature of the electrons after excitation and thermalization [4]. In our contribution we investigate the effect of radiative losses on the excitation of hot electrons, by comparing the hot electron dynamics in AuNP mono- and bilayers.
[1] ACS Cent. Sci. 2017, 3, 482-488 ; [2] J. Phys. Chem. Lett. 2017, 8, 19, 4925-4929 ; [3] ACS Photonics 2018, 5, 10, 3962-3969 ; [4] Chem. Rev. 2011, 111, 3858-3887.