Molecules detection in gaseous solutions is of great importance for controlled substances monitoring, food safety control and detection of highly toxic molecules. As general rule fast and efficient detection is request it, therefore the highest possible sensitivity is required. Raman signal is rich in information related with the structure and chemical composition but low in intensity. However, noble metal NPs are excellent candidates as plasmonic building blocks due to their ability of supporting localized surface plasmon resonances (LSPRs) when excited by visible light photons. To increase the Raman signal intensity, the interaction between the analyte and a metallic NP is exploited, where high intensity electric field regions are generated when their LSPR is excited by visible light. These regions amplify the Raman intensity generated and the resulting signal is called SERS (Surface Enhanced Raman Scattering). Moreover, if the metal nanoparticles (NPs) are very close to themselves, the electric field redistribution (LSPR coupling) yields local regions with intensity increments called hotspots which increase more the SERS signal intensity, lowering the detection limits. The main challenge for detection of molecules in gaseous solutions is to promote the interactions between the analyte and the probe surface. Therefore, a material which allows an efficient and high flow of gaseous solution at the surroundings of the plasmonic NPs is required. In this work, we proposed the inclusion of Au nanoparticles into low density materials as candidates to detect analytes from gaseous solutions. Three morphologies: spheres, rods and concave cubes are explored due to its different plasmonic response. The Au NPs concentration is also explored to modify their proximity with each other in the final material looking for the generation of hotspots.

Inclusion of plasmonic nanoparticles into low density materials

2019 Fall National Meeting

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