Surface Plasmon Coupling on Linked Au–Pt Nanorods

This work demonstrates that surface plasmon coupling in linked Au–Pt NRs (NRs) can be controlled by adjusting the relative ratio of material segment lengths. The NRs were synthesized through an anodic aluminum oxide template assisted sequential electrochemical deposition route. Optical spectra of the NRs in solution were acquired in the UV–vis–NIR region to examine surface plasmon coupling. Analysis of the spectra indicated that effective surface plasmon coupling could occur in Au-dominated NRs but not in Pt-dominated ones. The optical properties of Au–Pt–Au three-segment NRs were also examined, and the results provided further clarification regarding the conditions that yield effective coupling of NR segments in these structures. Electrodynamics calculations on two- and three-segment NRs were performed and found to be in good agreement with experiment. These findings regarding surface plasmon coupling of linked, hybrid NRs extend the fundamental knowledge of surface plasmon coupling from single component to hybrid systems and are useful for a variety of applications that necessitate fine controllability of the plasmonic properties.