This presentation describes the preparation and characterization of organic thin film-coated nano-porous plasmonic gold discs (NPGDs) as a substrate for detecting polycyclic aromatic hydrocarbons (PAHs) using surface enhanced Raman spectroscopy (SERS). NPGDs feature a unique combination of properties such as high-density plasmonic hot spots, intrinsic catalytic activities, clean surfaces, and large effective surface area. Hexyl-functionalized aryl-bisthiol (H(CH2)6OC6H3(CH2SH)2) (C6ArDT) was designed to be used as a robust adsorbate to form self-assembled monolayers (SAMs) on NPGD surfaces. The SAM molecules are used as a means for tuning the interfacial properties of the gold surface of the sensing substrate, thereby enhancing the interaction between the substrate with the target molecules. In addition, the incorporation of the bithiol headgroup as an anchoring moiety should offer long lifetimes for the organic monolayer. The performance of the generated NPGD random array was examined in the sensing of PAH molecules including pyrene, anthracene, benzo(a)pyrene, and benz(a)nthrace. In addition, the quality of the substrates was evaluated with respect to the adsorbate solution concentration-dependent gold-bound thiol percentage using X-ray photoelectron spectroscopy (XPS) analysis, and the Raman peak intensities of the PAH molecules as determined by SERS. This newly designed plasmonic substrate exhibits a SERS limit of detection of PAH molecules at concentrations as low as 2 μg/mL (or 10 μM). Keywords: Nano-porous Gold Discs (NPGD), Self-Assembled Monolayers (SAMs), Surface-Enhanced Raman spectroscopy (SERS). Acknowledgements: We thank the Bureau of Safety and Environmental Enforcement for the generous financial support (BSEE OSRR #1040). 'Statement of Disclaimer': This research does not represent BSEE's view.

Aryl bisthiolate functionalized plasmonic nanoporous discs: New direction for detecting polycyclic aromatic hydrocarbons using surface-enhanced Raman spectroscopy

251st National Meeting (2016)

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