Light trapping systems for biosensor application Forest of silica nanowires decorated with plasmonic nanoparticles

In this work we present a theoretical and experimental analysis of a new and cheaper plasmonic material, very attractive for its potential biosensing applications. We investigate the optical properties and the sensing capabilities of a highly disordered system of silica nanowires decorated with spherical gold nanoparticles. These systems present unique light trapping properties due to the combination of the highly diffusivity of transparent silica nanowires, with the selective absorption resonances given by Au nanoparticles deposited along the wires. The enhanced absorption at the LSPR resonances makes our materials excellent candidates to build plasmonic biosensors. The optical properties of these systems have been theoretically investigated by developing appropriate 2D finite element simulations. As proof of concept we have successfully tested the ability of the NP/NW forests to act as refractive index sensors and to detect biomolecular binding of the Protein BSA - AntiBSA bonding.