STM map of TIRE-immobilised citrate covered Ag nanoparticle(s) over PVD Au@SiO2 substrate using on-site etched Au tip; the scale bar is 5 nm. (2017)
Plasmonic enhanced Raman spectroscopy
The relatively low cross section of Raman scattering prevents routine application of Raman spectroscopy in cases where need arises to characterise solid state samples containing structures with thickness in the monolayer range or biomolecular samples in the range of physiological concentrations. Fortunately, the scattering efficiency can be improved using substrates with metalic nanostructures: by coupling of the excitation with suitably chosen wavelength resonantly to the electron plasma oscillations, rather high amplification of probing light can be achieved in the near field. In addition, the resonant enhancemenet can also come from inclusion of electronic transitions.
Focus points
- Resonant Raman spectroscopy (RRS)
continuous wavelength tunable excitation - SERS in colloids
Au spherical NP, Ag multistep prism NP
Au-Ag core-shell NP - TERS
AFM-TERS with Ag coated Si/SiO2 tips
STM-TERS with etched Au/Ag tips
high-resolution SPM
Equipment
Renishaw inVia
Fianium WhiteLase SC450 High-Power Supercontinuum (CEITEC)
NT-MDT Solar II + Ntegra spectra (CEITEC)
| cooperation: | TIRE group, multi particle materials properties group Karel Kubicek (biophysics), Jan Hrbac (SERS substrates, electrochemistry) |
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| external: | Petr Klapetek (AFM, FDTD simulations), Brno University of technology (SEM+EDX, AAO substrates) Zenobi group (TERS) |
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Papers
Halouzka V., Halouzkova B., Jirovsky D., Hemzal D., et al: Copper nanowire coated carbon fibers as efficient substrates for detecting designer drugs using SERS, Talanta 165(4), pp. 384-390 (2017)
Sharma V., Hynek D., Trnkova L., Hemzal D., et al: Electrochemical determination of adenine using a glassy carbon electrode modified with graphene oxide and polyaniline, Microchim Acta 183(4), pp. 1299-1306 (2016), link
Dried ambient STM map of TIRE-immobilised Rtt103 protein over atomically resolved PVD Au@BK7 substrate using on-site etched Au tip; the scale bar is 1 nm. (2017)
Reflectivity mapping of on-site etched Au STM tip in contact with Au@BK7 substrate at room ambient; the scale bar is 1 um. The inset shows higher resolution measurement overlayed with Raman map revealing the hot spot. (2017)
AFM phase image (air ambient) of Rtt103 protein CTD ineracting domain loaded via TIRE over Au/SiO2 substrate. Rtt103-CID is a predominantly helical peptide, some of the helices are resolved within the adsorbed molecules. The expected 2km4 structure of the peptide from pdb.org is overlayed (enlarged approx. 10x for better readability). (2016)
STM Au tip, as on-site etched; image courtesy of BUT. Note the high aspect ratio of the tip. (2016)