Kinetically Stable Nonequilibrium Gold‐Cobalt Alloy Nanoparticles with Magnetic and Plasmonic Properties Obtained by Laser Ablation in Liquid. Issue 7 (19th March 2021)

• Record Type: Journal Article
• Authors: Guadagnini, Andrea; Agnoli, Stefano; Badocco, Denis; Pastore, Paolo; Pilot, Roberto; Ravelle‐Chapuis, Régis; van Raap, Marcela B. Fernández; Amendola, Vincenzo
• Is Part Of: Chemphyschem. Volume 22:Issue 7(2021)
• Page Start: 657
• Page End: 664
• Publication Date: 2021-03-19
• Subjects: alloy nanoparticles -- gold nanoparticles -- cobalt nanoparticles -- laser ablation in liquid -- nonequilibrium alloy; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.202100021
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: Nonequilibrium nanoalloys are metastable solids obtained at the nanoscale under nonequilibrium conditions that allow the study of kinetically frozen atoms and the discovery of new physical and chemical properties. However, the stabilization of metastable phases in the nanometric size regime is challenging and the synthetic route should be easy and sustainable, for the nonequilibrium nanoalloys to be practically available. Here we report on the one‐step laser ablation synthesis in solution (LASiS) of nonequilibrium Au−Co alloy nanoparticles (NPs) and their characterization on ensembles and at the single nanoparticle level. The NPs are obtained as a polycrystalline solid solution stable in air and water, although surface cobalt atoms undergo oxidation to Co(II). Since gold is a renowned plasmonic material and metallic cobalt is ferromagnetic at room temperature, these properties are both found in the NPs. Besides, surface conjugation with thiolated molecules is possible and it was exploited to obtain colloidally stable solutions in water. Taking advantage of these features, an array of magnetic‐plasmonic dots was obtained and used for surface‐enhanced Raman scattering experiments. Overall, this study confirms that LASiS is an effective method for the formation of kinetically stable nonequilibrium nanoalloys and shows that Au−Co alloy NPs are appealing magnetically responsive plasmonic building blocks for several nanotechnological applications. Abstract : Appealing nonequilibrium nanoalloys : Nonequilibrium gold‐cobalt alloy nanoparticles were obtained in one‐step by laser ablation in liquid synthesis. The NPs are stable in air and water and exhibit appealing magnetic and plasmonic properties.