New Paper on the Study of the Localized Multipolar Surface Plasmon Resonances of Silver Nanoparticles Published in Langmuir.

Silver nanoparticles absorb and scatter light with extraordinary efficiency due to the collective oscillations of the conduction electrons of the metal surface when they are excited by light of an specific wavelengths. These oscillations, known as a localized surface plasmon resonances (LSPRs) are determined by the size, shape and local environment in which the nanoparticle is embedded. In this work, we have spectroscopically investigated the effect of the size and surface coating on the sensitivity of localized multipolar surface plasmon resonances in high-quality silver colloidal solutions with precisely controlled sizes from 10 to 220 nm and well-defined surface chemistry, identifying the size-dependence of dipolar, quadrupolar and octapolar modes. Besides, we studied how these multipolar resonances are affected by modifications of the NP’ surface coating, in particular the dependences on the length and the anchor group of the molecule attached at its surface, revealing the higher sensitivity of larger sizes, dipolar than higher-order modes, thiol than amine groups, and long than short molecules. We also extend this study to gold nanoparticles, aiming to compare the sensitivity of both materials, quantifying the higher sensitivity of silver. The work has now been published in Langmuir under the title “Quantifying the Sensitivity of Multipolar (Dipolar, Quadrupolar and Octapolar) Surface Plasmon Resonances in Silver Nanoparticles: The Effect of Size, Composition and Surface Coating.”