Drastic surface plasmon mode shifts in gold nanorods due to electron charging
Paul Mulvaney, Jorge Perez-Juste, Michael Giersig, Luis M Liz-Marzan, Carlos Pecharroman
PLASMONICS | SPRINGER | Published : 2006
The color of small gold rods changes dramatically when electrons are injected by chemical reductants. The longitudinal and transverse plasmon modes are both found to blue-shift, and the shift is larger for rods with larger aspect ratios. The color changes are visible to the eye for rods with aspect ratios around 2-3. It is found that the surface plasmon band is damped when charging becomes high. The effects are in qualitative agreement with a model in which the gold plasma frequency increases due to an increase in electron density. © Springer Science+Business Media, Inc. 2006.