Optical Property of a Colloidal Solution of Platinum and Palladium Nanorods: Localized Surface Plasmon Resonance

The optical properties of Pt and Pd nanorods as a function of aspect ratio were investigaed and systematically compared with Au nanorods of similar physical dimensions. The overall optical properties of Pt and Pd nanorods were tailored by controlling aspect ratio and could be tuned from 400 nm up to near-IR spectral window. Their longitudinal mode red shifts as the length increases, whereas the transverse mode blue shifts very slightly. The comparison of observed LSPR modes in Pt and Pd NRs with Au NRs as a function of aspect ratio exhibited that Pd NRs are most sensitive to variations in rod length. The magnitude of longitudinal mode shift per unit change of NR length could be obtained from the slope of a linear fit of each plot. Pd NRs show the largest dependence with a value ca. 6.72 (Delta lambda/Delta L). For Pt and Au NRs, the slope is ca. 4.23 and 3.11, respectively.