title: Effect of the dielectric constant of the surrounding medium and the substrate on the surface plasmon resonance spectrum and sensitivity factors of highly symmetric systems: silver nanocubes.
abstract: Silver nanocubes (AgNCs), 60 nm, have four extinction surface plasmon resonance (SPR) peaks. The finite difference time domain (FDTD) simulation method is used to assign the absorption and scattering peaks and also to calculate the plasmon field intensity for AgNCs. Because AgNCs have a highly symmetric cubic shape, there is a uniform distribution of the plasmon field around them, and they are thus sensitive to asymmetric dielectric perturbations. When the dielectric medium around a nanoparticle is changed anisotropically, either by placing the particle on a substrate or by coating it asymmetrically with a solvent, the plasmon field is distorted, and the plasmonic absorption and scattering spectra could shift differently. For the 60 nm AgNC, we found that the scattering resonance peak shifted more than the absorption peak. This changes the extinction bandwidth of these overlapping absorption and scattering bands, and consequently the figure of merit of the nanoparticle, as a localized SPR sensor, no longer has a constant value.
authors.affiliation: Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.
authors.forename: Mahmoud A
authors.initials: MA
authors.lastname: Mahmoud
authors.forename: Maysamreza
authors.initials: M
authors.lastname: Chamanzar
authors.forename: Ali
authors.initials: A
authors.lastname: Adibi
authors.forename: Mostafa A
authors.initials: MA
authors.lastname: El-Sayed
mesh_terms: D000042:Absorption; D004563:Electrochemistry / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry; D008855:Microscopy, Electron, Scanning / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D012542:Scattering, Radiation; D012834:Silver / Q000737:chemistry*; D020349:Surface Plasmon Resonance; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D012834:Silver