Drastic Surface Plasmon Mode Shifts in Gold Nanorods Due to Electron Charging

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.

[1]  N. Nakashima,et al.  UV–visible transmission–absorption spectral study of Au nanoparticles on a modified ITO electrode at constant potentials and under potential modulation , 2004 .

[2]  Feldmann,et al.  Drastic reduction of plasmon damping in gold nanorods. , 2002, Physical review letters.

[3]  E. Palik.  Handbook of Optical Constants of Solids , 1997 .

[4]  Paul Mulvaney,et al.  Surface Plasmon Spectroscopy of Nanosized Metal Particles , 1996 .

[5]  B. Nikoobakht,et al.  種結晶を媒介とした成長法を用いた金ナノロッド(NR)の調製と成長メカニズム , 2003 .

[6]  A. Henglein,et al.  Chemistry of Agn aggregates in aqueous solution: non-metallic oligomeric clusters and metallic particles , 1991 .

[7]  A. Henglein,et al.  Radiolytic Control of the Size of Colloidal Gold Nanoparticles , 1998 .

[8]  Paul Mulvaney,et al.  Drastic reduction of plasmon damping in gold nanorods. , 2002 .

[9]  Paul Mulvaney,et al.  Electric‐Field‐Directed Growth of Gold Nanorods in Aqueous Surfactant Solutions , 2004 .

[10]  Zhong Lin Wang,et al.  Surface Reconstruction of the Unstable {110} Surface in Gold Nanorods , 2000 .

[11]  Zhong Lin Wang,et al.  Crystallographic facets and shapes of gold nanorods of different aspect ratios , 1999 .

[12]  P. Mulvaney,et al.  Electro-optical shifts in silver nanoparticle films , 2001 .

[13]  Mostafa A. El-Sayed,et al.  Preparation and Growth Mechanism of Gold Nanorods (NRs) Using Seed-Mediated Growth Method , 2003 .

[14]  Paul Mulvaney,et al.  Spectroelectrochemistry of colloidal silver , 1997 .