Novel nano-plasmonic sensing platform based on vertical conductive bridge

Abstract

A novel nano-plasmonic sensing platform based on vertical conductive bridge was suggested as an alternative geometry for taking full advantages of unique properties of conductive junction while substantially alleviating burdens in lithographic process. The effects of various geometrical parameters on the plasmonic properties were systematically investigated. Theoretical simulation on this structure demonstrates that the presence of vertical conductive bridge with smaller diameter sandwiched between two adjacent thin nanodiscs excites a bridged mode very similar to the charge transfer plasmon and exhibits a remarkable enhancement in the extinction efficiency and the sensitivity when the electric field of incident light is parallel to the conductive bridge. Furthermore, for the electric field perpendicular to the bridge, another interesting feature is observed that two magnetic resonance modes are excited symmetrically through open-gaps on both sides of the bridge together with strongly enhanced electric field intensity, which provides a very favorable environment as a surface enhanced Raman scattering substrate for fluid analysis. These results verify a great potential and versatility of our approach for use as a nanoplasmonic sensing platform. In addition, we demonstrated the feasibility of fabrication process of vertical conductive bridge and high tunability in controlling the bridge width.

Plasmonic Nanostructures-Decorated ZIF-8-Derived Nanoporous Carbon for Surface-Enhanced Raman Scattering

“…Noble metal nanomaterials have been employed in a variety of biomedical applications, including imaging, drug delivery, and sensing. − Many of these applications rely heavily on their unique optical properties resulting from localized surface plasmon resonance (LSPR). − , Phenomenal progress in the synthesis of size- and shape-controlled plasmonic nanostructures with tunable LSPR wavelength in the visible range to parts of the near-infrared range has led to these nanostructures as powerful nanomaterials for analytical platforms. ,, The strong electric field on the surface of plasmonic nanostructures, as well as the hotspots formed between the nanostructures, suggests that the plasmonic nanostructures are ideal for SERS-based sensing applications. , Metal–organic frameworks (MOFs), consisting of metal ions or clusters linked by organic ligands, are a relatively new class of hybrid organic–inorganic supramolecular materials and have attracted great research attention due to their tunable porosity and large surface area. − These attractive properties, owing to their porous nature, render novel MOF materials for catalysts, gas storage, drug delivery, and chemical sensing. − Recently, porous carbon nanostructures have been demonstrated as an effective substrate for highly sensitive and biocompatible SERS sensing . The large chemical enhancement due to the strong broadband charge-transfer resonance and reproducible fabrication process makes porous carbon nanostructures promising SERS substrates.…”

“… 13 − 15 , 17 Phenomenal progress in the synthesis of size- and shape-controlled plasmonic nanostructures with tunable LSPR wavelength in the visible range to parts of the near-infrared range has led to these nanostructures as powerful nanomaterials for analytical platforms. 17 , 19 , 20 The strong electric field on the surface of plasmonic nanostructures, as well as the hotspots formed between the nanostructures, suggests that the plasmonic nanostructures are ideal for SERS-based sensing applications. 21 , 22 Metal–organic frameworks (MOFs), consisting of metal ions or clusters linked by organic ligands, are a relatively new class of hybrid organic–inorganic supramolecular materials and have attracted great research attention due to their tunable porosity and large surface area.…”