Visualizing individual molecules with chemical recognition is a longstanding target in catalysis, bio-science, nanotechnology, and materials science. Molecular vibrations provide a valuable “fingerprint” for this identification. The vibrational spectroscopy based on tip-enhanced Raman scattering (TERS) has opened a path to obtain enhanced vibrational signals thanks to the strong localized plasmonic field at the tip apex. In this talk, I shall demonstrate single-molecule Raman spectroscopic imaging with unprecedented sub-nm spatial resolution, resolving even the inner structure of a single molecule and its configuration on the surface [1]. This is achieved by a delicate plasmon enhanced nonlinear TERS technique, thanks to the exquisite tuning capability provided by low-temperature ultrahigh-vacuum scanning tunneling microscopy [2]. I shall also show the powerful application of this technique for chemically distinguishing adjacent different molecules in real space and address the issue of how close and how similar these different molecules can be. These findings should open up new avenues for probing and controlling nanoscale structures, catalysis, photochemistry, and even DNA sequencing, all at the sub-nm and single-molecule scale.
References
[1] R. Zhang, Y. Zhang, Z. C. Dong*, S. Jiang, C. Zhang, L. G. Chen, L. Zhang, Y. Liao, J. Aizpurua, Y. Luo, J. L. Yang , and J. G. Hou*, "Chemical mapping of a single molecule by plasmon enhanced Raman scattering", Nature 498, 82-86 (2013).
[2] Z. C. Dong*, X. L. Zhang, H. Y. Gao, Y. Luo, C. Zhang, L. G. Chen, R. Zhang, X. Tao, Y. Zhang, J. L. Yang, J. G. Hou*, “Generation of molecular hot electroluminescence by resonant nanocavity plasmons” , Nature Photonics 4, 50-54 (2010).
Dr. Zhen-Chao Dong is currently a full professor at Hefei National Laboratory for Physical Sciences at the Microscale (HFNL), University of Science and Technology of China (USTC). He graduated from Sichuan University in 1983 and received his M.S. degree in Xiamen University and Ph.D. degree from Fujian Institute on the Structure of Matter, Chinese Academy of Sciences (CAS) in 1990. Dong is now serving as the Director of Division of Atomic and Molecular Sciences at HFNL. His research interest is in the field of single-molecule optoelectronics and plasmonics, particularly on STM based single-molecule electroluminescence and single-molecule Raman scattering. The aim of his research is 1) to understand the underlying physics that governs the optoelectronic behavior of single molecules at the nanoscale, particularly on the light manipulation and energy transfer in a plasmonic nano-environment, and 2) to explore scientific basis for future technology related to information (e.g., nanoscale optoelectronic integration and quantum photon sources), energy (e.g., interface optoelectronic effects and OLED), and bio-science (e.g., bio-molecular imaging including DNA sequencing). Dong is currently the PI of several research projects supported by the Ministry of Science and Technology, the Chinese Academy of Sciences, and the National Natural Science Foundation of China. He has published more than 120 papers indexed by SCI (H-factor=26), including 8 first-author or corresponding-author papers in Nature, Nature Photonics, Phys. Rev. Lett., J. Am. Chem. Soc., and Angew. Chem. He has presented many invited talks in prestigious international conferences, including APS, ACS, IVC, ICN+T, NFO, NANOMETA, PIER, ChinaNANO, and ACSIN/ICSPM. He is the recipient of "National Outstanding Scientific and Technological Workers Award" from CAST in 2010, "the CAIA Outstanding Award" in 2013, "USTC President Award for Outstanding Research Achievements" in 2013, and "China's Top Ten Scientific and Technological Advances of 2013" Award.
Host: Jinfeng Jia jfjia@sjtu.edu.cn