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

Abstract

Highly ordered arrays of thiolated β ‐cyclodextrin (HS‐ β ‐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 H 3 PO 4 . 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‐ β ‐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‐ β ‐CD modified Ag‐NR arrays exhibit better capture ability and higher sensitivity in rapid detection of PCBs. Copyright © 2012 John Wiley & Sons, Ltd.