Nontrivial, Unconventional Electrochromic Behaviors of Plasmonic Nanocubes

Abstract

Plasmonic electrochromism, a change in the localized surface plasmon resonance (LSPR) with an applied electric potential, has been attracting increasing attention for the development of spectroscopic tools or optoelectronic systems. There is a consensus on the mechanism of plasmonic electrochromism based on the classical capacitor and the Drude model. However, the electrochromic behaviors of metallic nanoparticles in narrow optical windows have been demonstrated only with small monotonic LSPR shifts, which limits the use of the electrochromism. Here, we observed three distinct electrochromic behaviors of gold nanocubes with a wide potential range through in situ dark-field electrospectroscopy. Interestingly, the nanocubes show a faster frequency shift under the highly negative potential, and this opens the possibility of largely tunable electrochromic LSPR shifts. The reversibility of the electrochemical switching with these cubes are also shown. We attribute this unexpected change beyond classical understandings to the material-specific quantum mechanical electronic structures of the plasmonic materials.

Plasmon Energy Transfer Driven by Electrochemical Tuning of Methylene Blue on Single Gold Nanorods

“…Single-particle electrochemistry allowed the manipulation of the AuNR Fermi level and control of the MB redox chemistry by adding or removing electrons through the ITO electrode at negative or positive bias, respectively. Figure b shows how the electrochemical processes proceed using an equivalent circuit model following the flow of charge throughout the system . The ITO and AuNRs are in Ohmic contact (R interlayer ), and the interface between AuNRs and the electrolyte is capacitive (C AuNRs ) and makes a connection serially.…”

“…Figure 1b shows how the electrochemical processes proceed using an equivalent circuit model following the flow of charge throughout the system. 37 The ITO and AuNRs are in Ohmic contact (R interlayer ), and the interface between AuNRs and the electrolyte is capacitive (C AuNRs ) and makes a connection serially. Additional processes, including Faradaic reactions, mainly the redox reaction of MB (represented by R AuNRs ), form a parallel connection to C AuNRs .…”

Nanoscale Manipulation of Exciton–Trion Interconversion in a MoSe2 Monolayer via Tip-Enhanced Cavity-Spectroscopy

“…61,62 Further, we observe three stronger TECS PL spots, such as both edges and the center of the AuNW, due to the strong Coulomb interaction. Electrons of the Au tip form strong dipole with the positive surface charges of the AuNW, 63 at both edges and the center. At these three spots, we can also observe the expanded area of enhanced PL along the perpendicular direction with respect to the NW axis because the TECS configuration can also be formed when the Au tip is located on the side of the AuNW.…”

Nanoscale manipulating plasmonic silver adatoms for dynamic light modulation

“…Through electrochemical control from the application of voltage stimuli, dynamic color displays, generated by noble metal nanoparticles (e.g., Ag, Au), have been realized in a variety of platforms. [9][10][11][12] This class of electrochromic devices not only can switch between multiple colors but also retains their colored states without the need for external electrical power. 13 Recently, Ag nanoparticles, having tunable nanostructures, along with their localized surface plasmon resonance (LSPR), have been investigated for multicolor electrochromic films.…”