Large-area Ag nanorod array substrates for SERS: AAO template-assisted fabrication, functionalization, and application in detection PCBs

Highly ordered arrays of thiolated beta-cyclodextrin (HS-beta-CD) functionalized Ag-nanorods (Ag-NRs) with plasmonic antennae enhancement of electrical field have been achieved for encapsulation and rapid detection of polychlorinated biphenyls (PCBs). The large-area ordered arrays of rigid Ag-NRs supported on copper base were fabricated via porous anodic aluminum oxide (AAO) template-assisted electrochemical deposition. The inter-nanorod gaps between the neighboring Ag-NRs were tuned to sub-10?nm by thinning the pore-wall thickness of the AAO template using diluted H3PO4. The nearly perfect large-area ordered arrays of Ag-NRs supported on copper base render these systems excellent in surface-enhanced Raman scattering (SERS) performance with uniform electric field enhancement, as testified by the SERS spectra and Raman mappings of rhodamine 6?G. Furthermore, the Ag-NRs were functionalized with HS-beta-CD molecules so as to capture the apolar PCB molecules in the hydrophobic cavity of the CD. Compared to the ordinary undecorated SERS substrates, the HS-beta-CD modified Ag-NR arrays exhibit better capture ability and higher sensitivity in rapid detection of PCBs. Copyright (C) 2012 John Wiley & Sons, Ltd.