10.1021/ja300901e.s001 Mahmoud A. Mahmoud Mahmoud A. Mahmoud Maysamreza Chamanzar Maysamreza Chamanzar Ali Adibi Ali Adibi Mostafa A. El-Sayed Mostafa A. El-Sayed 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 American Chemical Society 2012 nanoparticle extinction surface plasmon resonance Silver NanocubesSilver nanocubes absorption SPR plasmon field Surface Plasmon Resonance Spectrum difference time domain plasmon field intensity dielectric 60 nm AgNC FDTD 2012-04-11 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/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/2531893 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.