title: Stoichiometry of alloy nanoparticles from laser ablation of PtIr in acetone and their electrophoretic deposition on PtIr electrodes.
abstract: Charged Pt-Ir alloy nanoparticles are generated through femtosecond laser ablation of a Pt₉Ir target in acetone without using chemical precursors or stabilizing agents. Preservation of the target's stoichiometry in the colloidal nanoparticles is confirmed by transmission electron microscopy (TEM)-energy-dispersive x-ray spectroscopy (EDX), high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM)-EDX elemental maps, high resolution TEM and selected area electron diffraction (SAED) measurements. Results are discussed with reference to thermophysical properties and the phase diagram. The nanoparticles show a lognormal size distribution with a mean Feret particle size of 26 nm. The zeta potential of -45 mV indicates high stability of the colloid with a hydrodynamic diameter of 63 nm. The charge of the particles enables electrophoretic deposition of nanoparticles, creating nanoscale roughness on three-dimensional PtIr neural electrodes within a minute. In contrast to coating with Pt or Ir oxides, this method allows modification of the surface roughness without changing the chemical composition of PtIr.
authors.affiliation: Materials and Processes Department, Laser Zentrum Hannover, Hollerithallee 8, 30419 Hannover, Germany.
authors.forename: Jurij
authors.initials: J
authors.lastname: Jakobi
authors.forename: Ana
authors.initials: A
authors.lastname: Menéndez-Manjón
authors.forename: Venkata Sai Kiran
authors.initials: VS
authors.lastname: Chakravadhanula
authors.forename: Lorenz
authors.initials: L
authors.lastname: Kienle
authors.forename: Philipp
authors.initials: P
authors.lastname: Wagener
authors.forename: Stephan
authors.initials: S
authors.lastname: Barcikowski
mesh_terms: D000096:Acetone / Q000737:chemistry*; D000497:Alloys / Q000737:chemistry; D003102:Colloids / Q000138:chemical synthesis / Q000737:chemistry; D003461:Crystallography; D004566:Electrodes; D004586:Electrophoresis; D007495:Iridium / Q000032:analysis / Q000737:chemistry*; D007834:Lasers; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D017348:Microscopy, Electron, Scanning Transmission; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D010984:Platinum / Q000032:analysis / Q000737:chemistry*; D012542:Scattering, Radiation; D013052:Spectrometry, X-Ray Emission; D055672:Static Electricity; D013499:Surface Properties; D013816:Thermodynamics; D014835:Volatilization
chemical_list: D000497:Alloys; D003102:Colloids; D000096:Acetone; C077763:platinum-iridium alloy; D007495:Iridium; D010984:Platinum