Chemical Analysis with Nanoscale to Angstrom Scale Resolution Heading link

— presented by Jeremy F. Schultz

For the list of references, please visit our Youtube channel.

Projects Heading link

TERS

Characterizing the chemical behavior of individual molecules and the underlying reaction mechanisms via nanoimaging and nanospectroscopy  

We are developing a hybrid technique, which combines nanoimaging and nanospectroscopy, to harvest sub-molecular resolution topographic information and chemical information with unprecedented spatial and spectroscopic resolution. SPM can provide quantitative information on surface morphology, such as the locations and binding configurations of molecular adsorbates on solid substrates. Then our TERS spectroscopic signals will be strongly enhanced by plasmonic probes, providing us with the ability to follow single-molecule processes at specific binding sites on solid surfaces. Our novel methods not only provides new fundamental insight into the mechanistic studies of chemical reactions, but also guides the rational design of complex systems at the interface of chemistry and materials science.
TERS 2

Probing chemistry of surface-supported nanostructure at the angstrom-scale   

The design and fabrication of well-defined molecular nanostructures at solid surfaces is highly attractive for a variety of applications ranging from molecular optics and electronics to chemical sensors. To achieve this goal, we use molecular self-assembly, a powerful bottom-up approach for fabricating molecular nanostructures. The ordering of molecules on a substrate is governed by the interplay of intermolecular and interfacial interactions. We directly probe these nanocontacts using SPM and TERS. With specifically chosen molecular units, the functionality of the overall nanostructure can be finely manipulated, which allows us to design and perfect atom- and energy-efficient fabrication of revolutionary new materials with tailored properties.
2D material

Investigating Local Structural and Chemical Properties of Atomically Thin Two-Dimensional Materials 

In order to develop new two-dimensional (2D) materials and tune the atomic structure and electronic structure towards unique and functional properties, it becomes critical to understand and subsequently harness highly localized environments and phenomena. We are dedicated to the development of a novel optical Scanning Tunneling Microscopy (STM) approach to image and characterize the local vibrational and electron-phonon coupling properties of nano- and atomic-scale heterogeneity.  Such advanced understanding is essential for fine-tuning the properties of 2D structures for electronics, photonics, sensing, and energy harvesting applications.

TERS 3

Determining the mechanism of chemical bond formation under various local environments  

The catalysts and supports span a range of materials, shapes and sizes. They feature a variety of surface defects and a great deal of crystallographic inhomogeneity. Catalysis involves chemical transformations that must be understood at the atomic scale since catalytic reactions present an intricate process of chemical bond-breaking and bond-forming steps on only a few isolated sites. The development of next-generation catalysts relies on defining and understanding the sites on the catalyst surface which are most responsible for their useful behavior. We aim to identify and characterize surface active sites at the atomic scale, which can be used to correlate the local structure and function of catalysts.
plasmonic

Probing Photochemical Process via Nano-Confined Plasmons

Through illuminating the nanogap between the plasmonically active STM tip and the metallic surface by visible light, the plasmons can be excited, and a confined, intense electromagnetic (EM) field can be generated at the tip apex. In an effort to overcome these obstacles, we have developed a noble approach (i.e., atomistic approach) that associates approaching the plasmonically active STM Ag tip extremely close to the molecule (few-Å). This approach enables us to squeeze the surface plasmon in the sub-nanometer scale and investigate the selective activation of a specific bond, in presence of multiple chemically indistinguishable chemical bonds inside a single molecule. We aim to elucidate the detailed underlying mechanisms of plasmon-induced surface chemical reactions at the single chemical bond level (< 1 nm).

Instrumentation Heading link

Funded by: Heading link

UIC

University of Illinois Chicago Startup

National Science Foundation

National Science Foundation (NSF)

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ACS PRF

ACS Petroleum Research Fund (ACS-PRF)