Séminaire LISE | Nan Jiang "Angstrom scale chemical analysis via scanning tunneling microscopy..."

A la suite du congrès TERS8, le LISE vous convie à un séminaire sous l'égide de l'Institut des Sciences et Ingénierie Moléculaire présenté par

Nan Jiang (Associate professor et leader du groupe Nano Chicago)

"Angstrom Scale Chemical Analysis via Scanning Tunneling Microscopy and Tip-Enhanced Raman Spectroscopy"

My research group is interested in investigating how local chemical environments affect single-molecule behaviors with angstrom scale resolution. This talk will start from 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;1 (2) adsorbate-substrate interactions in the ordering of molecular building blocks in supramolecular nanostructures;2 (3) atomic-scale insights into the oxygen reactivity of 2D materials;3(4) local strain effects in an organic/2D materials heterostructure.4 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 wavenumber) resolution. Another application of localized surface plasmons is to achieve site-selective chemical reactions at 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 scanning probe microscopy tip-controlled plasmonic resonance.5 Our method can interrogate the mechanisms of forming and breaking chemical bonds at the angstrom scale in various chemical environments, which is critical in designing new atom- and energy-efficient materials and molecular assemblies with tailored chemical properties.

Reference:
1. S. Mahapatra, Y. Ning, J. F. Schultz, L. Li, J. -L. Zhang, N. Jiang
Angstrom Scale Chemical Analysis of Metal Supported Trans- and Cis-Regioisomers by Ultrahigh Vacuum Tip-Enhanced Raman Mapping
Nano Letters,19, 3267-3272 (2019).
2. J. F. Schultz, L. Li, S. Mahapatra, C. Shaw, X. Zhang, N. Jiang
Defining Multiple Configurations of Rubrene on a Ag(100) Surface with 5 Angstrom Spatial Resolution via Ultrahigh Vacuum Tip-Enhanced Raman Spectroscopy
The Journal of Physical Chemistry C, 124, 2420-2426 (2020).
3. L. Li, J. F. Schultz, S. Mahapatra, X. Zhang. X. Liu, C. Shaw, M. Hersam, N. Jiang
Probing interfacial interactions in an organic/borophene heterostructure with angstrom resolution
Journal of the American Chemical Society, 143, 38, 15624-15634 (2021).
4. L. Li, J. F. Schultz, S. Mahapatra, Z. Lu, X. Zhang, and N. Jiang
Chemically identifying single adatoms with single-bond sensitivity during oxidation reactions of borophene
Nature Communications, 13, 1796 (1-9) (2022).
5. S. Mahapatra, J. F. Schultz, L. Li, X. Zhang, and N. Jiang
Controlling Localized Plasmons via an Atomistic Approach: Attainment of Site-Selective Activation inside a Single Molecule
Journal of the American Chemical society, 144, 5, 2051-2055 (2022).