Simulating Plasmon Resonances of Gold Nanoparticles with Bipyramidal Shapes by Boundary Element Methods

TL;DR

This paper models the localized surface plasmon resonance of gold nanobipyramids using boundary element methods, highlighting the importance of geometry and size in accurate simulations for applications in bioimaging and nanophotonics.

Contribution

It introduces a detailed simulation approach for GNBs, emphasizing the role of geometrical averaging and size considerations in modeling LSPR properties.

Findings

Spherical tip models best match experimental spectra

Geometry averaging improves model accuracy

Quasi-static approximation applicability depends on nanoparticle size

Abstract

Computational modeling and accurate simulations of localized surface plasmon resonance (LSPR) absorption properties are reported for gold nanobipyramids (GNBs), a class of metal nanoparticle that features highly tunable, geometrydependent optical properties. GNB bicone models with spherical tips performed best in reproducing experimental LSPR spectra while the comparison with other geometrical models provided a fundamental understanding of base shapes and tip effects on the optical properties of GNBs. Our results demonstrated the importance of averaging all geometrical parameters determined from transmission electron microscopy images to build representative models of GNBs. By assessing the performances of LSPR absorption spectra simulations based on a quasi-static approximation, we provided an applicability range of this approach as a function of the nanoparticle size, paving the way to the theoretical study of the coupling between molecular electron densities and metal nanoparticles in GNB-based nanohybrid systems, with potential applications in the design of nanomaterials for bioimaging, optics and photocatalysis.