Holey gold nanowires formed by photoconversion of dissipative nanostructures emerged at the aqueous-organic interface

Gold nanowires with nanocavities were produced by photochemical reduction of Au(OH)₄-/tetra-alkyl ammonium ion pairs that are preorganized specifically under far-from-equilibrium conditions. Aqueous solution containing Au(OH)₄-ion was layered on a chloroform solution of tetrabutylammonium hexafluorophosphate (TBAPF6). UV light was then vertically illuminated to the interface without stirring, so that Au(III) ions self-assembled at the interface are reduced under the far-from equilibrium condition. 1mL of acetonitrile was added to the dark aqueous phase, and the mixture was centrifuged at 15000 rpm. The X-ray photoelectron spectroscopy (XPS) revealed sharp peaks at binding energies of 84.0 eV and 87.9 eV, which are assigned to emissions from electrons of Au. The osmotic pressure revealed by tetra-alkylammonium ions in the organic phase drives their vectorial transport across the interface, which flux assists the self-organization of ion pairs into dissipative nanostructures.