Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 59: Plasmonics and Nanooptics
O 59.26: Poster
Dienstag, 21. März 2017, 18:30–20:30, P2-OG1
Surface-enhanced infrared spectroscopy with nanorod antenna arrays for investigating alkanethiols with different chain lengths — •Tobias W. W. Mass, Andreas F. Hessler, and Thomas Taubner — Institute of Physics (IA) RWTH Aachen
Metallic structures can efficiently couple light into a region of subwavelength size. In these regions, large local field enhancements can occur and enable an increased light absorption of molecules which are placed in these so called "hot spots". Arrays of nanorod antennas which are designed for surface-enhanced infrared absorption (SEIRA) spectroscopy enable the detection of molecular vibrations with high sensitivity [1,2].
Alkanethiol molecules of different chain length differ only in their number of CH2-groups, while they all have one single CH3-group. It has been shown with grazing incidence reflection spectroscopy that the absorption signals from the CH2-groups depend linearly on the chain length, while those of the CH3-groups stay constant [3].
In our work, we investigated how well we can distinguish small quantities of alkanethiol molecules by SEIRA spectroscopy. We calculated the quotient of the absorption signals of the CH2- and CH3-groups, which is largely independent of the specific nanoantenna geometries and observed a linearly rising trend.
[1] C.Huck et al., ACS Nano 8, 4908 (2014)
[2] T.W.W.Maß and T.Taubner., ACS Photonics 2, 1498 (2015)
[3] M.D.Porter et al., J. Am. Chem. Soc. 109, 3559 (1987)