Core-shell super-spherical nanoparticles for LSPR-based sensing platforms

Boosted by the progresses in nano-optics, highly sensitive and label-free optical transducers for sensing applications have been proposed over the last years. Among them, plasmonic nanoparticle based transducers have had a great success because their resonant behavior is extremely sensitive to the changes of the local surrounding environment, being interesting candidates for real-time measurements and diagnoses. Here, we propose the employment of the core-shell super-spherical nanoparticle to design new sensing devices. We demonstrate that, thanks to this particular geometry, a sensor working in the visible spectrum may exhibit an higher sensitivity with respect to all the conventional solutions currently adopted in the field. The analysis is conducted by developing an analytical model for the polarizability of the core-shell super-spherical particle and verified through a proper set of numerical experiments. Finally, the sensing performances of the core-shell super-spherical nanoparticle are discussed and compared with the state-of-the-art optical sensors working in the same frequency range.