Triangular metal nanoprisms of Ag, Au, and Cu: Modeling the influence of size, composition, and excitation wavelength on the optical properties

Abstract

We describe herein a systematic investigation on the optical properties of Ag, Au, and Cu triangular nanoprisms as a function of size and excitation wavelength using the discrete dipole approximation. Specifically, the edge length was varied from 40 to 100nm while the thickness was kept at 10nm. In the far field, our results suggest that the in-plane localized surface plasmon resonance (LSPR) peaks red-shifted as the edge length increased. In the near field, the magnitude of the electric fields generated close to the surface of the nanoprisms were calculated considering 514, 633, and 785nm as the excitation wavelengths. The variation on the magnitude of the electric fields can be understood based on the matching between the excitation wavelength and the position of the in-plane dipole and quadrupole LSPR modes. We believe that these results can have important implications in the design of metal nanoprisms for plasmonic applications.