Tunable Electrochemical Switch of the Optical Properties of Metallic Nanoparticles

Abstract

Control of the optical properties of oblate metallic nanoparticles (NP) is realized using an electrochemical switch consisting of a thin layer of conducting polymer (CP). Reversible modulation, moderate damping, and almost total quenching of the localized surface plasmon (LSP) resonance is achieved as a function of the thickness of the CP layer and the potential applied to the electrochemical systems, that is, the charge carrier density injected into the CP layer. These experimental results can be qualitatively reproduced using the single-particle model in the electrostatic approximation. We believe that combining an electroactive conducting polymer and NP will prove to be a general strategy for controlling the properties of various types of NP (fluorescent, magnetic, semiconducting) in many fields.

Tunable Plasmon Resonance of Gold Nanoparticles Functionalized by Electroactive Bisthienylbenzene Oligomers or Polythiophene

“…25,27,29 As for these other conducting polymers, this blue-shift can be qualitatively explained by the Drude free-electron model. 46− 48 We can assume that the dielectric function (ε) of polythiophene in its reduced state is real, whereas in its oxidized state it is complex (ε = ε Re + iε Im ).…”

“…50 and 100 nm, respectively. 27 In the case of PEDOT, a giant blue-shift of 192 nm was even measured for a film thickness of about 150 nm. 29 Similar active plasmonic devices were obtained by Baba et al 30 In such studies, the electroactive layers were weakly bonded to the NP, and the interfaces between the NP and the electroactive layers were not controlled.…”

Conducting polymer–gold co-patterned surfaces via nanosphere lithography

“…Moreover, overlapping absorption spectra was observed by UV-Vis absorption spectroscopy, a potential alternate transduction and/or absorption switching method. As compared to previously reported conducting polymer/Au matrices [11][12][13], the proposed protocol incorporates complementary patterns of both components instead of random co-deposition. Spatially arranging these materials presents more control for plasmonic and absorption properties as a function of periodicity and amount of material deposited.…”

“…Among its characteristics, its capability to electrochemically switch from an oxidized to a reduced state (or conductive state to an insulating state) is arguably the most vital since a complete change in properties can be observed. Recently, reports have investigated synergistic properties of hybrid polyaniline-Au materials and demonstrated modulation and damping of the LSPR peak as controlled by the potential-dependent doping state of the conducting polymer [11][12][13]. With these properties, nanostructured arrays comprising of Au and conducting polymers have great potential as materials for active plasmonic devices and electrochemical sensors [14].…”

Electrochemical Modulation of the Optical Property of Polythiophene-Gold Nanorod Composite Films

“…LSPR frequency depends mainly on size, shape, electron density, and aggregated condition of nanoparticles, and furthermore on the index of surrounding medium. Modulating of LSPR frequency over a few tenths of nanometers was achieved by controlling the electron density [1] or by changing the index of electrochromic materials [2,3].…”