A Tunable Nanoplasmonic Mirror at an Electrochemical Interface
By Ma, Ye; Zagar, Cristian; Klemme, Daniel J.; Sikdar, Debabrata; Velleman, Leonora; Montelongo, Yunuen; Oh, Sang-Hyun; Kucernak, Anthony R.; Edel, Joshua B.; Kornyshev, Alexei A.
Published in ACS Photonics
2018
Abstract
Designing tunable optical metamaterials is one of the great challenges in photonics. Strategies for reversible tuning of nanoengineered devices are currently being sought through electromagnetic or piezo effects. For example, bottom-up self-assembly of nanoparticles at solid | liquid or liquid | liquid interfaces can be used to tune optical responses by varying their structure either chemically or through applied voltage. Here, we report on a fully reversible tunable-color mirror based on a TiN-coated Ag substrate immersed in an aqueous solution of negatively charged Au-nanoparticles (NPs). Switching electrode potential can be used to fully control the assembly/disassembly of NPs at the electrode | electrolyte interface within a 0.6 V wide electrochemical window. The plasmon coupling between the electrode and the adsorbed NP array at high positive potentials produces a dip in the optical reflectance spectrum, creating the