Electrotunable nanoplasmonic liquid mirror

Abstract

Recently, there has been a drive to design and develop fully tunable metamaterials for applications ranging from new classes of sensors to superlenses among others. Although advances have been made, tuning and modulating the optical properties in real time remains a challenge. We report on the first realization of a reversible electrotunable liquid mirror based on voltage-controlled self-assembly/disassembly of 16 nm plasmonic nanoparticles at the interface between two immiscible electrolyte solutions. We show that optical properties such as reflectivity and spectral position of the absorption band can be varied in situ within ±0.5 V. This observed effect is in excellent agreement with theoretical calculations corresponding to the change in average interparticle spacing. This electrochemical fully tunable nanoplasmonic platform can be switched from a highly reflective 'mirror' to a transmissive 'window' and back again. This study opens a route towards realization of such platforms in future micro/nanoscale electrochemical cells, enabling the creation of tunable plasmonic metamaterials.

Air‐Liquid Interfacial Self‐Assembly of Two‐Dimensional Periodic Nanostructured Arrays

“…Another typical way is by introducing an electronic field across the interface, which allows the dynamical assembly and/or disassembly of the charged NPs at the interface. For instance, Kornyshev's group demonstrated a voltage‐controlled self‐assembly/disassembly method (dynamic assembly) to form a reversible electro‐tunable liquid mirror of negative‐charged AuNPs at the liquid‐liquid interface . As the system was placed in an electrochemical cell, it allowed to dynamically control the assembly (adsorption) and disassembly (desorption) of NPs at the liquid‐liquid interface by changing the polarity of the applied electronic field across the interface, as shown in Figure C.…”

“…[78] In contrast, dynamic self-assembly is a process which requires continuous energy input to grow and sustain. [78] A serial of external energy stimuli, such as light, [79] electric, [80] and/or magnetic field, [78] have been applied to dynamically control the assembly or disassembly of NPs at the interface. For example, Kanaras et al developed a light-induced evaporation method to organize AuNPs in a polymer matrix.…”

“…[80] Images reproduced with permission from Ref. [80] Copyright 2017 Springer Nature Publishing AG. (D) Schematic illustration of the dynamic selfassembly of the AuNPs at air-liquid interface by adding or removing the solvent from the liquid surface.…”

Self‐Assembly of Nanoparticles in 2D and 3D: Recent Advances and Future Trends

“…Montelongo et al [299] have reported the design of electrotunable liquid mirror consisting of plasmonic nanoparticles at the interface between two immiscible electrolyte solutions. The reversibility of the self-assembly/disassembly and the average interparticle spacing could be controlled through the variation of voltage and, therefore, can be switched in a reversible manner from a highly reflective "mirror" to a transmissive "window."…”

Self‐Assembled Gold Arrays That Allow Rectification by Nanoscale Selectivity

“…[29][30][31] However, these channels only produce ar ectification ratio (RR) when the channel reaches ac ertain thickness.G old nanoparticles (AuN Ps) can selfassemble into ordered nanoscale monolayer arrays. [32][33][34][35][36][37] Herein, we describe the generation of asymmetric ion transport with nanoscale selectivity by transferring ag old monolayer nanoarray onto an anodized aluminum oxide (AAO) surface to form ah eterostructured membrane.T he channel displayed asymmetric ion transport when the monolayer gold nanoarray was placed on the surface of ac ylindrical AAO substrate.T he ion selectivity was amplified by increasing the number of gold nanoarray layers,w hen the monolayer gold nanoarray was the structural unit (Supporting Information, Figure S1). Theion-selective mechanism at the nanoscale was uncovered.…”