An ultrahigh-sensitivity plasmonic antenna (NIMA)
Researchers using surface enhanced Raman scattering (SERS) are always on the look out for new substrates that take advantage of coupled metallic nanoparticles to improve sensitivity. In this HOT article, researchers from Taiwan have introduced NIMAs (nanoparticle (NP)-imprinted mirror antennas) for exactly this purpose.
The researchers deposited Ag on a polycarbonate substrate and used Si molds to create 2D periodic nanostructures, which were then used to create NIMAs by self-assembling Ag nanoparticles onto the Ag mirrors. The formation of 2D nanoclusters on the mirror results in more intense Raman signals as a result of electromagnetic coupling between the NPs in the clusters. NIMAs have several advantages over other SERS-active substrates. For example, NIMAs gain broadband enhancement from single structures, rather than from various substrates with different morphologies. Also, using a deeper, more consistent structure and tuning the surface plasmon resonance (SPR) modes can drastically improve the SERS enhancement observed from NIMAs.
The researchers have produced a SERS-active substrate that is compatible in the visible to near-infrared regime and is capable of detecting rhodamine 6G at a concentration as low as 10-15 M. These attractive advantages should be enough for any SERS researcher to reflect on the possibility of adopting NIMAs as a sensing platform in the future.
Dr Lee Barrett is a guest web writer for the Nanoscale blog. Lee is currently a postdoctoral researcher in the Centre for Molecular Nanometrology at the University of Strathclyde. His research is currently focused on the development of nanoparticle-based sensors and surface enhanced Raman scattering (SERS).
