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Our group focuses on applying scanning probe-based nanotechnology, including scanning probe microscopy (SPM) and tip enhanced Raman spectroscopy (TERS), to design, synthesize and characterize new nanomaterials and molecular assemblies. We are interested in fundamental science and applications at the nano-scale, including charge transfer, electron localization and generation, photoabsorption and photoemission, which are at the heart of the next generation single-molecule devices.
Investigating the chemical behavior of individual molecules 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. This novel approach allows us to understand how the remarkable properties of materials emerge from the complex correlations of atomic constituents. Our goal is to predict and control energy transfer in single molecules, as seen in photovoltaic and photosynthetic materials.
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.
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.
- Jiang, N. Chiang, L. R. Madison, E. A. Pozzi, M. R. Wasielewski, T. Seideman, M. A. Ratner, M. C. Hersam, G. C. Schatz, and R. P. Van Duyne, “Nanoscale Chemical Imaging of a Dynamic Molecular Phase Boundary with Ultrahigh Vacuum Tip-Enhanced Raman Spectroscopy”, Nano Lett.,16, 3898-3904 (2016)
- Chiang, X. Chen, G. Goubert, D. V. Chulhai, X. Chen, E. A. Pozzi, N. Jiang, M. C. Hersam, T. Seieman, L. Jensen, and R. P. Van Duyne， “Conformational Contrast of Surface-Mediated Molecular Switches Yields Angstrom-Scale Spatial Resolution in Ultrahigh Vacuum Tip-Enhanced Raman Spectroscopy”, Nano Lett., 16, 7774 (2016).
- Jiang, D Kurouski, E. A. Pozzi, N. Chiang, M. C. Hersam, and R. P. Van Duyne, “Tip-Enhanced Raman Spectroscopy: From Concepts to Practical Applications”, Chem. Phys. Lett., 659, 16 (2016).
- Chiang, N. Jiang, D. Chulhai, E. Pozzi, M. C. Hersam, L. Jensen, T. Seideman and R. P. Van Duyne, “Molecular-Resolution Interrogation of Porphyrin Monolayer by Ultrahigh Vacuum Tip-Enhanced Raman and Fluorescence Spectroscopy”, Nano Lett., 15, 4114-4120 (2015).
- M. Klingsporn, N. Jiang, E. A. Pozzi, M. D. Sonntag, D. Chulhai, T. Seideman, L. Jensen, M. C. Hersam, and R. P. Van Duyne, “Intramolecular Insight into Adsorbate-Substrate Interactions via Low Temperature, Ultrahigh Vacuum Tip-Enhanced Raman Spectroscopy”, J. Am. Chem. Soc.,136, 3881-3887 (2014).
- Jiang, E. T. Foley, J. M. Klingsporn, M. D. Sonntag, N. A. Valley, J. A. Dieringer, T. Seideman, G. C. Schatz, M. C. Hersam, and R. P. Van Duyne, “Observation of Multiple Vibrational Modes in Ultrahigh Vacuum Tip-Enhanced Raman Spectroscopy Combined with Molecular-Resolution Scanning Tunneling Microscopy”, Nano Lett., 12, 5061-5067 (2012).
- Jiang, Y. Y. Zhang, Q. Liu, Z. H. Cheng, Z. T. Deng, S. X. Du, H. -J. Gao, M. J. Beck, and S. T. Pantelides, “Diffusivity control in molecule-on- metal systems using electric fields”, Nano Lett., 10, 1184-1188 (2010).
- Jiang, Y. L. Wang, Q. Liu, Y. Y. Zhang, Z. T. Deng, K. -H. Ernst, and H. -J. Gao, “Polymorphism and chiral expression in two-dimensional subphthalocyanine crystals on Au(111)”, Phys. Chem. Chem. Phys., 12, 1318-1322 (2010).
BS, University of Science and Technology of China, 2004
PhD, Chinese Academy of Sciences, 2010
Joint PhD student, Max Planck Institute for Solid State Research, 2008-2009
Postdoctoral Fellow, Northwestern University, 2010-2015.