title: Bifunctional Fe3O4/Ag nanoparticles obtained by two-step laser ablation in pure water.
abstract: OBJECTIVE
  Bimetallic nanoparticles made of iron oxide and Ag could be fabricated by pulsed laser ablation of iron and silver targets in pure water by a two-step route. These nanoparticles could exhibit both magnetic and plasmonic properties.
  
  
  METHODS
  Bimetallic nanoparticles were fabricated by using a focused Nd:YAG nanosecond laser source emitting a 1064nm wavelength radiation and characterized with ζ-potential, Dynamic Light Scattering (DLS), UV-vis absorption, Transmission Electron Microscopy (TEM), High Resolution TEM (HRTEM), Energy Dispersive X-ray Spectrometry (EDX), and Selected Area Electron Diffraction (SAED). The magnetic character of the nanoparticles was ascertained by observing attraction by a magnet and complete removing from the water environment, while their SERS (surface-enhanced Raman scattering) response was checked by decorating them with 2,2'-bipyridine as molecular reporter and performing Raman tests with green (514.5nm) and far-red (785nm) excitation wavelengths.
  
  
  RESULTS
  The observed magnetic attraction was due to magnetite (Fe3O4), the only ferromagnetic iron oxide form evidenced by the characterization tests in the aqueous colloidal system, where silver nanoparticles were also embedded. UV-vis and SERS spectra confirmed the presence of nanostructured silver as plasmonic constituent of the fabricated metal nanoparticles.
authors.affiliation: Department of Chemistry Ugo Schiff", University of Florence, Via Lastruccia 3, 50019 Sesto Fiorentino, Italy. Electronic address: maurizio.muniz@unifi.it.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Muniz-Miranda
authors.affiliation: Department of Chemistry Ugo Schiff", University of Florence, Via Lastruccia 3, 50019 Sesto Fiorentino, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Gellini
authors.affiliation: Institute of Complex Systems (ISC-CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy.
authors.forename: Emilia
authors.initials: E
authors.lastname: Giorgetti
authors.affiliation: Institute of Complex Systems (ISC-CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Margheri
keywords: Laser ablation; Magnetite; Nanoparticles; SERS; Silver