Core-Shell Super-Spherical Nanoparticles for LSPR-Based Sensing Platforms

Boosted by the progresses in nanooptics, 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 a 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.