Direct Writing of Metal Nanoparticles by Localized Plasma Electrochemical Reduction of Metal Cations in Polymer Films

Abstract

A non-lithographic, dry approach to patterning metal nanoparticles is presented. Solutions of metal salt and polymer are spin-coated onto a substrate, dried, and exposed to a rastered microscale plasma operated at atmospheric pressure and room temperature. Interaction of the electrons in the plasma with the fi lm results in electrochemical reduction of the metal cations to crystalline metal nanoparticles. The process is highly localized, making it possible to obtain microscale patterns of metal nanoparticles with line widths as small as ∼ 30 μ m. We have applied this technique to a wide range of metals such as Ag, Au, Pt, Ir, and Ru, in various polymeric systems such as polyvinyl alcohol (PVA) and poly(methyl methacrylate) (PMMA). Overall, the approach allows the fabrication of transparent, fl exible, patterned fi lms of metal nanoparticles at low cost and high throughput for applications ranging from plasmonics to catalysis.

Transparent, conductive gold nanowire networks assembled from soluble Au thiocyanate

“…Previous studies have reported reduction of Au ions following application of plasma treatment. 13 SEM data presented in Fig. S3, ESI, † indicate that the plasma reduction process gave rise to pronounced morphological changes within the nanowire surface, which are consistent with the spectroscopic results in Fig.…”

Porous Gold Nanotubes for Enhanced Methanol Oxidation Catalysis

“…Echoing the XPS data in Figure A, air plasma treatment transformed all gold into the crystalline metallic organization ( Figure B,ii ). Previous studies have similarly shown that plasma treatment can efficiently reduce metal cations …”

Patterning of metal oxide thin films using a H 2 /He atmospheric pressure plasma jet

“…16 We have shown that helium plasma at atmospheric pressure in the absence of hydrogen was effective at reducing copper oxide films, suggesting that electrons alone are, in the case of copper, sufficient for the reduction process. 17 This view is supported by Lee et al 18 and Sui et al 19 who loaded metal ions in a polymer matrix and showed using an APPJ that the reduction of the metal ions was indeed driven by plasma (or secondary) electrons.…”