Localized surface plasmon resonance of truncated Au nanotriangle dimers with bowtie arrangement

Abstract

Localized surface plasmon resonance (LSPR) is a unique optical property of metallic nanoparticles which is important for various application. There are many factors affecting LSPR, including geometry, composition, assembly, and surrounding environment. In this work, we studied the LSPR of Au nanotriangles with sharp and truncated tips using MNPBEM simulation. We also studied the effect of truncation in nanotriangle dimers with bowtie arrangement. The simulation results show a linear correlation between extinction peak wavelength and the nanotriangle edge length. Larger nanotriangles display more than one extinction peaks in the visible and near-infrared range. Bowtie arrangement of two sharp nanotriangles results in a red shift of the first extinction peak compared to that of the monomer. Truncating the tips of nanotriangles causes blue shift of extinction peak wavelength. However, at low truncation, the peak wavelength of nanotriangle dimers is red shifted. In addition, the extinction peak wavelength decreases as the gap distance in between two nanotriangles increases. This study demonstrated the manipulation of nanotriangle LSPR by modifying the tips of the nanotriangle, in addition to modifying the dimension and arrangement between two nanotriangles.