Well-Controlled Synthesis of Au@Pt Nanostructures by Gold-Nanorod-Seeded Growth

Pt nanodots were formed oil Au nanorods (NRs) by using a simple seed-mediated growth. Their density and distribution on the Au NR can he finely tuned by varying the reaction parameters. At lower Pt/Au ratios, the Pt nanodots mainly appear at endcaps and side edges of the Au rod. At higher Pt/Au ratios, they distribute homogeneously over the whole Au rod. The obtained Pt nanostructure is a single crystal owing to the epitaxial growth of Pt on the Au rod. Due to the unique surface plasmon resonance (SPR) features of the AU NRs. the Au core/Pt shell (AU@Pt) nanostructures also exhibit well-defined and red-shifted longitudinal SPR hands in the visible and near-infrared region. The position and intensity can be regulated by the thickness and amount of the Pt shell. At a thinner Pt thickness, the Au@'Pt NRs show higher dielectric sensitivity than the corresponding Au NRs. It thus opens up the potential of Pt nanostructures for SPR-based sensing.