Exploiting reducing ability of DMF for assembled gold nanostructures

Abstract

We explore stable assembly of gold NPs in single step process by introducing a simple chemical synthesis in which pH changed gold precursor is added to dimethylformamide solution at RT. The redox chemistry of N, N-dimethylformamide (DMF) has been effectively utilized in the formation of surfactant free, small chain metal NPs networks (plasmonic oligomers) via molecular dipolar coupling. Kinetic absorption / TEM images illustrate gold nanocrystals formation, their inter-particle coupling as a function of pH as well as with DMF-Water ratio. Subnano gap inter-particle coupling b/w spherical/anisotropic Au NPs is seen through arising of new LSPR hump in NIR region. 1-D organized gold nanocrystals are formed when pH modified metal precursor is added to refluxed (80 0C) DMF: Water mixture. The inter-particle coupling provides unique strategy can promote complex sub-wavelength optical waveguides and nanophotonic devices.