Optical properties of nanoalloys

Abstract

The optical properties of multi-component metal nanostructures (or nanoalloys) are the subject of an intense and rapidly growing experimental and theoretical activity. In this perspective article, we first provide a survey of the most recent developments in the field, concerning both theoretical methods, especially at the first-principles level, and novel results, distinguishing for the convenience of presentation the sub-field of monolayer-protected multi-component metal clusters from the other alloy nanosystems. We then discuss a few general concepts which can be drawn from this survey, and offer a few suggestions on the most promising directions for future research. We hope that making the point in this fast developing field will provide a framework and a perspective useful to trigger future studies and advancements.

Intense fluorescence of Au20

“…Since all previous studies were either performed on ligand-protected or protein-encapsulated Au clusters, [12][13][14][15][16] it has remained unclear whether the fluorescence is intrinsic to the Au cluster or emerging from its interaction with ligands, and the considerable theoretical effort dedicated to the simulation of absorption spectra [17][18][19][20][21] and fluorescence 22 has not answered this question. For bare Au clusters, experiments were limited to cluster sizes below the relevant one.…”

Design of a fluorescent and clickable Ag38(SRN3)24 nanocluster platform: synthesis, modeling and self-assembling

“…The single-cluster structure generated from step (i) has also been used (iii) to predict the optical response of these systems, to be compared with experimental absorption spectra in solution as customary. 71 These three steps then correspond to different simulation methods. We employed Monte Carlo Global Optimization (GO) techniques to unravel the atomic arrangement of the Ag 38 S 24 fragment; using Time-Dependent Density-Functional Theory (TDDFT) simulated optical properties; and nally we resorted to classical molecular dynamics for studying, by annealing techniques, the organization of interacting Ag 38 (SRN 3 ) 24 clusters in the solid state.…”

Structure-conserving spontaneous transformations between nanoparticles

“…Atomically precise nanoparticles of noble metals12345678910, often called nanoclusters, which constitute an exploding discipline in nanomaterials, are promising candidates to explore such transformations because of their well-defined structures and drastic changes in their properties, in comparison to their bulk form, arising due to electronic confinement. Most intensely explored of these properties are optical absorption and emission1112131415; near infrared emission of some of the clusters and their large quantum yields have resulted in new applications1617181920. Nanoparticles are generally considered stable and are expected to preserve their structural integrity in solution.…”