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

Abstract

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.

Quantum description of the optical response of charged monolayer–thick metallic patch nanoantennas

“…The induced electron density ∆n DP (r) = n(r, t * ) − n(r, t = 0) is obtained from the time-dependent electron density n(r, t) by exposing the system to the linearly z-polarized electromagnetic wave with frequency Importantly, when Q electrons are added to the system, the change of the absorption spectra predicted by the classical theory, is not confirmed by the TDDFT calculations even qualitatively. Indeed, for the 2D-systems it is commonly assumed that the extra charge is homogeneously distributed over the nanoobject [26][27][28][47][48][49][50][51] , so that the plasmon frequency changes as ∆w p /w p = 0.5Q/N e . Thus, within this assumption, in the classical calculations the plasmon modes experience a blue-shift with increasing Q as shown in Fig.…”

“…In this context, understanding of the quantum/classical correspondences in individual and coupled plasmonic systems when they are subjected to external perturbations allows to develop efficient strategies of the active control. Indeed, active control of the plasmonic modes by applied dc fields [42][43][44][45][46] or charging [47][48][49][50] has been reported in the literature. In particular, if possible for metallic nanostructures 51,52 , the plasmon frequency change via electron doping as known in the THz range for semiconductor quantum wells or graphene [26][27][28][29][53][54][55] would allow active ultracompact devices in the visible range.…”

Plasmon-induced artificial photosynthesis

“…Thus, the electron density in Au-NIs was considered to affect the peak wavelength of rsfs.royalsocietypublishing.org Interface Focus 5: 20140082 the plasmon resonance spectrum. The localized surface plasmon resonance wavelength (l) is defined according to the following equation [30,31]:…”

Shifts in plasmon resonance due to charging of a nanodisk array in argon plasma

“…LSPRs of metal nanostructures depend on properties such as the size, 10,11 shape, [12][13][14] metal material, 15 surrounding dielectric material, [16][17][18][19][20][21][22] and the charge of the metal. [23][24][25][26][27][28][29][30] Active plasmonic devices can be realized by externally tuning the LSPR of nanostructures. Previously, chemical/electrochemical charging was used to actively tune the LSPR of arrays of both silver 24,25,30 and gold 23,26,27,29 nanostructures; however, this process is relatively slow.…”

“…[23][24][25][26][27][28][29][30] Active plasmonic devices can be realized by externally tuning the LSPR of nanostructures. Previously, chemical/electrochemical charging was used to actively tune the LSPR of arrays of both silver 24,25,30 and gold 23,26,27,29 nanostructures; however, this process is relatively slow. In this study, a rapid shift in the LSPR of an array of gold nanodisks was induced by surrounding the particles with a low-temperature argon plasma.…”