Team achieves breakthrough in molecular imaging

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Published Aug 13, 2013

A breakthrough in the development of optical imaging technology has been achieved by KTH Royal Institute of Technology and the University of Science and Technology of China (USTC).

The research team has achieved unprecedented sub-nanometre resolution with Raman spectroscopy, opening the way for significant advancement in nanophotonics, biochemistry, surface science and molecular electronics.

In an article published in Nature (June 6, 2013), the team states that the ability to explore the nanometer-scale world could lead to new ways to “design, control and engineer the functionality of molecules on demand.”

The project team includes Yi Luo, a professor in the department of Theoretical Chemistry and Biology at KTH’s school of Biotechnology.

Raman spectroscopy is used to study the structure of molecules, based on how photons interact with molecular bonds. Recent enhancements in the Raman effect have been possible by adsorbing molecules to metallic nanoparticles to create electronic oscillations – or plasmons – on the metal’s surface. But the best spatial resolution attainable with the most advanced technique, using the tip of an atomic force microscope as the metal surface, has been limited to 3−15 nanometres. Nevertheless, that resolution is not adequate for resolving a single molecule chemically.

The USTC/KTH team , led by Professor Zhencao Dong at USTC, has shown that by with a scanning tunnelling microscope, the resolution can be increased dramatically. The tuning capability of scanning tunnelling microscopy is so precise that it can match the resonance of the nanocavity plasmon to the molecular vibronic transitions, particularly the downward transition responsible for the emission of Raman photons.


 

By doing so the team achieved a spatial resolution of about 0.5 nanometres (within a 10 to 90 percent contrast), with chemically resolved information revealing intramolecular features.


In addition to the article in Nature, the research was reported in 40 different articles in scientific magazines, particularly those covering nanotechnology and molecular electronics.

Scholarly reference: "Chemical mapping of a single molecule with (sub-nm) resolution of plasmonökad Raman scattering." R. Zhang, Y. Zhang, ZC Dong, S. Jiang, C. Zhang, LG Chen, L. Zhang, Y. Liao, J. Aizpurua, Y. Luo, JL Yang and JG Hou. Nature 498 (2013) 82, DOI: 10.1038/nature12151.

For more information, contact Yi Luo at 08 - 55 37 84 14 or luo@kth.se.
 

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