Three-dimensional plasmonic materials for chemical sensor application

In this work, we perform a numerical and experimental comparison of 2D and 3D systems of plasmonic nanostructures in order to explore several key parameters for sensitivity enhancement of traditional LSPR biosensors. The optical properties and the sensing capabilities of planar and three-dimensional distributions of metal nanostructures have been theoretically and experimentally investigated. We developed a numerical model for calculating the absorption spectra and the sensitivity towards increasing refractive indexes of periodic array of plasmonic nanostructures. Our numerical results have been verified performing a sensitivity comparison of 2D and 3D nanostructured systems composed by the same kind of metal nanoparticles. As proof of concept, our experiment were conducted on a planar distribution of gold nano-spheres and an hybrid 3D plasmonic material composed by a disordered system of silica nanowires decorated with spherical gold nanoparticles.