Optical properties of Au-core Pt-shell nanorods studied using FDTD simulations

Abstract

Au-core/Pt-shell nanorods (Au@Pt NRs) have been prepared by a Au nanorod-mediated growth method, and they exhibit high electromagnetic field enhancements under coupling conditions. Boosted by a long-range effect of the high electromagnetic field generated by the Au core, the electromagnetic field enhancement can be controlled by changing the morphology of the nanostructures. In this study, we report the results on the simulations of the electromagnetic field enhancement using a finite difference time domain (FDTD) method, taking the real shapes of the Au@Pt NRs into account. Due to the “hot spot” effect, the electromagnetic field can be localized between the Pt nanodots. The electromagnetic field enhancement is found to be rather independent of the Pt content, whereas the local roughness and small sharp features might significantly modify the near-field. As the electromagnetic field enhancement can be tuned by the distribution of Pt nanodots over the Au-core, Au@Pt NRs can find potential applications in related areas.