title: Strong dependence of surface plasmon resonance and surface enhanced Raman scattering on the composition of Au-Fe nanoalloys.
abstract: Nanoalloys of noble metals with transition metals are crucial components for the integration of plasmonics with magnetic and catalytic properties, as well as for the production of low-cost photonic devices. However, due to synthetic challenges in the realization of nanoscale solid solutions of noble metals and transition metals, very little is known about the composition dependence of plasmonic response in nanoalloys. Here we demonstrate for the first time that the elemental composition of Au-Fe nanoalloys obtained by laser ablation in liquid solution can be tuned by varying the liquid environment. Due to surface passivation and reaction with thiolated ligands, the nanoalloys obtained by our synthetic protocol are structurally and colloidally stable. Hence, we studied the dependence of the surface plasmon resonance (SPR) on the iron fraction and, for the first time, we observed surface enhanced Raman scattering (SERS) in Au-Fe nanoalloys. SPR and SERS performances are strongly affected by the iron content and are investigated using analytical and numerical models. By demonstrating the strong modification of plasmonic properties on the composition, our results provide important insights into the exploitation of Au-Fe nanoalloys in photonics, nanomedicine, magneto-plasmonic and plasmon-enhanced catalysis. Moreover, our findings show that several other plasmonic materials exist beyond gold and silver nanostructures.
authors: Department of Chemical Sciences, University of Padova, via Marzolo 1, I-35131 Padova, Italy. vincenzo.amendola@unipd.it.
authors: Vincenzo
authors: V
authors: Amendola
authors: Stefano
authors: S
authors: Scaramuzza
authors: Stefano
authors: S
authors: Agnoli
authors: Stefano
authors: S
authors: Polizzi
authors: Moreno
authors: M
authors: Meneghetti
mesh_terms: D000497:Alloys; D003102:Colloids / Q000737:chemistry; D020342:Finite Element Analysis; D006046:Gold / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007834:Lasers; D008024:Ligands; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D008962:Models, Theoretical; D055095:Optics and Photonics; D012031:Refractometry; D012997:Solvents; D013059:Spectrum Analysis, Raman; D013438:Sulfhydryl Compounds / Q000737:chemistry; D020349:Surface Plasmon Resonance; D013499:Surface Properties
chemical_list: D000497:Alloys; D003102:Colloids; D008024:Ligands; D012997:Solvents; D013438:Sulfhydryl Compounds; D006046:Gold; D007501:Iron