Unveiling multimodal hot carrier excitation in plasmonic bimetallic Au@Ag nanostars for photochemistry and SERS sensing

Plasmonic nanostructures stand at the forefront of nanophotonics research,particularly in sensing and energy conversion applications.Their unique ability to confine light energy at the nanoscale makes them indispensable for a wide array of technological advancements.The study of these structures often makes use of different materials and,even more extensively,explores new shapes and configurations to extend our common repertoire of useful nanophotonics tools.Exploring the creation of bimetallic plasmonic nanostructures combines these two dimensions determining the space of possible plasmonic resonators and opens the possibility of tailoring systems with behavior unavailable to single-metal plasmonic structures.In this paper,we delve into the exploration of bimetallic systems employing plasmonic nanostars.These structures have demonstrated remarkable capabilities for surface-enhanced Raman scattering(SERS)spectroscopy and photochemistry,due to the strong plasmonic response of their peaks,whose disposition following a spherical symmetry makes them largely polarization-and orientationinsensitive.Herein,we report the colloidal synthesis of two different water-stable Au@Ag nanostars,explore their performance as photocatalysts and SERS substrates,and provide an in-depth account of their non-trivial physical response.

The versatility of Fe(Ⅱ) in the synthesis of uniform citrate-stabilized plasmonic nanoparticles with tunable size at room temperature

A highly versatile seed-mediated approach for the synthesis of citrate-stabilized gold,silver and palladium nanoparticles(NPs)with size control is reported.The use of iron(Ⅱ)as a reducing agent enables the fabrication of monodisperse NPs in a wide range of sizes(from 15 nm to at least 120 nm(90 nm for Pd))at room temperature.The citrate as capping ligand on the NPs surface facilitates its further surface modification with proteins and thiolated molecules.