Abstract

During the last decade, the photothermal properties of nanostructures have attracted an increasing interest for both fundamental and applied aspects, with potential impact on cancer therapy and solar devices [1]. In particular, metal nanoparticles have been widely exploited to absorb and concentrate light energy at the nanoscale, via plasmonic resonances. Most efforts in the field have dealt with the engineering of the individual nanoparticle configuration, from nanospheres to nanorods, nanoshells, nanocages, etc. (see e.g. Ref. 2 for an overview). Another route of research explored novel materials for plasmonics, including heavily doped semiconductors, and even all-dielectric materials with peculiar permittivity enabling quasi-static resonances without free carriers (see e.g. ref. 3 and references therein). However, the available degrees of freedom turned out to be relatively limited. A fresh new turn in the field is represented by plasmonic nanocrystal assemblies, i.e. so-called supraparticles or supracrystals of about 100 nm, consisting of few nm-sized metallic nanocrystals embedded in a matrix of organic ligands [4]. Thanks to their hybrid composition and their internal structure, these novel nanomaterials offer unprecedented possibilities for the engineering of both linear and nonlinear plasmonic phenomena.

© 2019 IEEE