Abstract
Pulsed laser-induced dewetting (PLiD) of Ag0.5Ni0.5 thin films results in phase-separated bimetallic nanoparticles with size distributions that depend on the initial thin film thickness. Co-sputtering of Ag and Ni is used to generate the as-deposited (AD) nanogranular supersaturated thin films. The magnetic and optical properties of the AD thin films and PLiD nanoparticles are characterized using a vibrating sample magnetometer, optical absorption spectroscopy, and electron energy loss spectroscopy (EELS). Magnetic measurements demonstrate that Ag0.5Ni0.5 nanoparticles are ferromagnetic at room temperature when the nanoparticle diameters are >20 nm and superparamagnetic <20 nm. Optical measurements show that all nanoparticle size distributions possess a local surface plasmon resonance (LSPR) peak that red-shifts with increasing diameter. Following PLiD, a Janus nanoparticle morphology is observed in scanning transmission electron microscopy, and low-loss EELS reveals size-dependent Ag and Ni LSPR dipole modes, while higher order modes appear only in the Ag hemisphere. PLiD of Ag-Ni thin films is shown to be a viable technique to generate bimetallic nanoparticles with both magnetic and plasmonic functionality.
| Original language | English |
|---|---|
| Pages (from-to) | 19285-19292 |
| Number of pages | 8 |
| Journal | ACS Omega |
| Volume | 5 |
| Issue number | 30 |
| DOIs | |
| State | Published - Aug 4 2020 |
Funding
P.D.R. and D.A.G. acknowledge support from the National Science Foundation (CBET-1603780). I.N.V and J.D.F. acknowledge support from the US Department of Energy (DOE) under grant number KC 0403040 ERKCZ01. G.P. acknowledges the National Science Foundation (NSF DMR 1709275). D.A.G. (Gilbert) and N.T. acknowledge support from the DOE Early Career Program and National Science Foundation (NSF 2028542). All the authors acknowledge that the absorption and EELS measurements was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.