Veranstaltungen
26. März 2024, 16:00 bis 17:00
Nan Jiang, Department of Chemistry, University of Illinois Chicago, USA
Seminar
My research group is interested in investigating how local chemical environments affect nanostructure properties with Ångström scale resolution. This talk will start with Tip-Enhanced Raman Spectroscopy (TERS), which affords the spatial resolution of traditional Scanning Tunneling Microscopy (STM) while collecting the chemical information provided by Raman spectroscopy. By using a plasmonically active material for our scanning probe, the Raman signal at the tip-sample junction is incredibly enhanced, allowing for single-molecule probing. This method, further aided by the benefits of ultrahigh vacuum, is uniquely capable of controlling localized plasmons via an atomistic approach. We are able to obtain (1) single-molecule chemical identification; (2) structural identification of new synthetic 2D materials; (3) atomic-scale insights into the oxygen reactivity of 2D materials; (4) local strain effects in an organic/2D materials heterostructure. By investigating substrate structures, superstructures, 2D materials lattices, and the adsorption orientations obtained from vibrational modes, we extract novel surface-chemistry information at an unprecedented spatial (< 1 nm) and energy (< 10 wavenumbers) resolution. Another application of localized surface plasmons is to achieve site-selective chemical reactions at a sub-molecular scale. We recently selectively and precisely activated multiple chemically equivalent reactive sites one by one within the structure of a single molecule by STM tip-controlled plasmonic resonance. Our method can interrogate the mechanisms of forming and breaking chemical bonds at the Ångström scale in various chemical environments, which is critical in designing new atom- and energy-efficient materials and molecular assemblies with tailored physical and chemical properties.
Veranstaltung Details
- Veranstaltungsort
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SEM.R. DB gelb 05 B
1040 Wien
Wiedner Hauptstraße 8-10/E134 - Veranstalter
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IAP
Manuela Marik
marik@iap.tuwien.ac.at - Öffentlich
- Ja
- Kostenpflichtig
- Nein
- Anmeldung erforderlich
- Nein