Novel supra-molecular arrangements with plasmonic functionalities for fipronil pesticide detection

Plasmonic devices are of great interest for different applications including chemical sensing for food and water contaminants. Their properties to confine high electromagnetic fields strictly depend on the size, shape and, more in general, on the geometry of their basic constituents. In this work we fabricate and characterize two-dimensional periodic arrangements of novel plasmonic supra-molecular cells with different minimum intercell distance and in both nanopillars and nanocavities geometries. For patterns based on nanopillars we evaluate the bulk sensitivity associated to their localized surface plasmon resonance which results to have a value up to 408 nm/RIU while for the patterns based on nanocavities we found a SERS enhancement factor up to 2.1x106. We tested the sensing performance of these nanostructures analyzing different concentrations in water of fipronil pesticide using both LSPR and SERS tools. Our results suggest that these plasmonic patterns are promising to develop nanosensors for a dual-sensing detection of water contaminants with high sensitivity.