Nature Inspired Plasmonic Structures: Influence of Structural Characteristics on Sensing Capability

Abstract

Surface enhanced Raman scattering (SERS) is a powerful analytical technique that allows the enhancement of a Raman signal in a molecule or molecular assemblies placed in the proximity of nanostructured metallic surfaces, due to plasmonic effects. However, laboratory methods to obtain of these prototypes are time-consuming, expensive and they do not always lead to the desired result. In this work, we analyse structures existing in nature that show, on a nanoscale, characteristic conformations of photonic crystals. We demonstrate that these structures, if covered with gold, change into plasmonic nanostructures and are able to sustain the SERS effect. We study three different structures with this property: opal, a hydrated amorphous form of silica (SiO 2 •nH 2 O); diatoms, a kind of unicellular alga; and peacock tail feather. Rhodamine 6G (down to 10 −12 M) is used to evaluate their capability to increase the Raman signal. These results allow us to define an alternative way to obtain a high sensitivity in Raman spectroscopy, currently achieved by a long and expensive technique, and to fabricate inexpensive nanoplasmonic structures which could be integrated into optical sensors.

Optics and Spectroscopy for Fluid Characterization

“…Finally, liquid-solid interactions can also be used in a chemical sensing, in particular using surface-enhanced Raman scattering (SERS) spectroscopy, where the plasmonic enhancement of an electromagnetic field in the presence of nanostructured metal surfaces is utilized. Perozziello and co-workers [19] demonstrate that the development of new and efficient SERS substrates can be inspired by nature. They use natural nanomaterials with suitable structures and cover them with a thin gold layer.…”

Tuning SERS Signal via Substrate Structuring: Valves of Different Diatom Species with Ultrathin Gold Coating

“…Each of the thousands of species discovered so far has a unique morphology, valve geometry, and pore pattern [ 12 ]. Other examples of biomaterials used in fabrication of hybrid SERS substrates include peacock feathers and opal [ 19 ], as well as butterfly wings [ 20 ].…”