Colloidal phase behavior as a toolbox for reconfigurable plasmonics

Nanoparticles (NPs) made from noble metals such as gold and silver exhibit unique optical properties arising from the localized surface plasmon resonance, i.e. the collective oscillation of free electrons driven by light. This effect leads to the confinement of intense electromagnetic fields at the NP interface, making plasmonic nanostructures ideal building blocks for nanoscale optical devices.

A key feature of these systems is the possibility to tune their optical response by controlling NP size, shape, and organization. As a result, the collective optical properties of NP assemblies are not intrinsic, but emerge from their spatial arrangement. This makes NPs particularly suitable for a bottom-up design approach, in which optical functionalities can be engineered by introducing programmable interactions among NPs to guide their assembly.

In this seminar, I will show how concepts from soft matter physics can be leveraged to control the assembly of plasmonic NPs and thereby tailor their collective optical response by dynamically tuning interparticle interactions and phase behavior. I will present different strategies to direct NP organization by exploiting their integration with other functional colloidal specie, including proteins and thermoresponsive polymeric microgels. These systems enable control over interparticle distances and spatial correlations via reversible and stimuli-responsive interactions, providing access to reconfigurable optical responses.