Facile synthesis of spinous-like Au nanostructures for unique localized surface plasmon resonance and surface-enhanced Raman scattering

Abstract

By changing the ratios of two cationic surfactants, cetyltrimethylammonium bromide (CTAB) and cetyltrimethylammonium chloride (CTAC), irregular quasi-spherical AuNPs, popcorn-shaped AuNPs, ricepaper pith shaped AuNPs and the spinous-like Au nanostructures were synthesized via a convenient seed-mediated method. The composition of the as-prepared uniform Au nanostructure was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The differences in shape and kinetics mechanism were well explained by morphological changes arising from using different ratios of the two surfactants. Systematical analysis revealed that the generation of Au nanostructures with different shapes, including different degrees of curvature of the tips and the differences in shape strongly depended on controlling the ratios of the two surfactants which further affect their localized surface plasmon resonance (LSPR) properties in both visible and near-infrared regions. Moreover, the spinous-like Au nanostructures showed obvious surface-enhanced Raman scattering activity for crystal violet (CV) dye, which implied that the irregular quasi-spherical AuNPs, popcorn-shaped AuNPs, rice paper pith shaped AuNPs and the spinous-like Au nanostructures could be used in applications such as electronics, catalysis, and imaging.