Simple Fabrication of Two-Dimensional Self-Assemblies Consisting of Gold and Silver Nanoparticles at an Air/Toluene Interface and Their Surface-Enhanced Raman Scattering Activity

摘要

A methodology for fabricating two-dimensional assemblies consisting of octadecylamine-stabilized gold, silver, and mixed gold and silver nanoparticles at an air/toluene droplet interface is reported. After evaporation of the toluene solvent, the structure and optical properties of the resulting high-density nanoparticle assemblies were evaluated by transmission absorption spectroscopy and scanning electron microscopy (SEM). In addition, an investigation of the surface-enhanced Raman scattering (SERS) activity of para-mercaptoaniline molecules adsorbed on these assemblies revealed that by increasing the mixing ratio of silver nanopartictes to gold nanoparticles, SERS signals were significantly enhanced due to an adjustment in the excitation wavelength of surface plasmon resonance and an enhancement of the local electromagnetic field.