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Winton Programme for the Physics of Sustainability

Department of Physics


Bachelor and Master in Materials Science from the University of Stuttgart, Germany


Few Molecule Vibrational Spectroscopy in Plasmonics

Gold nanoparticle assembled into nanoarchitectures can be used to investigate single molecules using surface enhanced Raman spectroscopy (SERS). This high sensitivity arises from the fact that incoming light can couple to collective electron vibrations in the gold nanoparticles creating fields which are tightly confined at the particle surface. By using two or more adjacent nanoparticles these states couple together to form highly localised states on the 1 nm scale, in the so-called hotspots. The Raman signal of molecules in such a hotspot is extremely amplified by over billion-fold allowing the detection of single molecules. However, the signal strongly depends on the geometry of the nano-architecture. Assembling structures with a reliable geometry and nanometre-precise control over the gap between the nanoparticle remains a major challenge.

For my research I am using molecular systems, like self-assembled monolayers or hybrid lipid bilayers assembled inside individual gold nanostructures. I am investigating the influence of a molecular conductivity on the plasmon resonances as well as the dynamic behaviour of these molecular systems by SERS in real time.


Key publications: 
  1. Benz F, Schmidt MK, Dreismann A, Chikkaraddy R, Zhang Y, Demetriadou A, Carnegie C, Ohadi H, de Nijs B, Esteban R, Aizpurua J, Baumberg JJ. Single-molecule optomechanics in “picocavities”. Science 354, 726-729 (2016); doi:10.1126/science.aah5243
  2. Chikkaraddy R, de Nijs B, Benz F, Barrow SJ, Scherman OA, Rosta E, Demetriadou A, Fox P, Hess O, Baumberg JJ. Single-molecule strong coupling at room temperature in plasmonic nanocavities. Nature 535, 127-130 (2016); doi:10.1038/nature17974
  3. Benz F, Chikkaraddy R, Salmon A, Ohadi H, de Nijs B, Mertens J, Carnegie C, Bowman RW, Baumberg JJ. SERS of Individual Nanoparticles on a Mirror: Size Does Matter, but so Does Shape. The Journal of Physical Chemistry Letters 7, 2264–2269 (2016); doi:10.1021/acs.jpclett.5b02535
  4. Lombardi A, Demetriadou A, Weller L, Andrae P, Benz F, Chikkaraddy R, Aizpurua J, Baumberg JJ. Anomalous Spectral Shift of Near- and Far-Field Plasmonic Resonances in Nanogaps. ACS Photonics 3, 471–477 (2016); doi:10.1021/acsphotonics.5b00707
  5. Benz F, de Nijs B, Tserkezis C, Chikkaraddy R, Sigle DO, Pukenas L, Evans SD, Aizpurua J, Baumberg JJ. Generalized circuit model for coupled plasmonic systems. Optics Express 23, 33255–33269 (2015). doi:10.1364/OE.23.033255
  6. Benz F, Tserkezis C, Herrmann LO, de Nijs B, Sanders A, Sigle DO, Pukenas L, Evans SD, Aizpurua J, and Baumberg JJ. Nanooptics of Molecular-Shunted Plasmonic Nanojunctions. Nano Letters 15, 669-674 (2015); doi:10.1021/nl5041786
  7. de Nijs B, Bowman RW, Herrmann LO, Benz F, Barrow SJ, Sigle DO, Mertens J, Eiden A, Ferrari A, Scherman OA, and Baumberg JJ. Unfolding the contents of sub-nm plasmonic gaps using normalising plasmon resonance spectroscopy. Faraday Discussions 178, 185-193 (2015); doi:10.1039/C4FD00195H
  8. Taylor RW, Benz F, Sigle DO, Bowman RW, Bao P, Roth JS, Heath GR, Evans SD, and Baumberg JJ, Watching individual molecules flex with lipid membranes using SERS. Scientific Reports 4, 5940 (2014); doi:10.1038/srep05940
Winton Scholar
Supervisor: Prof Jeremy Baumberg
Nanophotonics Group
Mr Felix  Benz

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