Electrochemistry on Inverse Copper Nanoantennas: Active Plasmonic Devices with Extraordinarily Large Resonance Shift

Arrays of metallic nanoparticles can be used for plasmonic color printing. However, the development of dynamic plasmonic color displays capable of controllable and reversible switching of individual pixels is still in its infancy. Here, an active plasmonic device that operates at the border between the visible and the near-infrared spectral region using inverse copper nanoantennas is introduced. This is a suitable choice, as copper can easily and reversibly be oxidized and reduced with the method of cyclic voltammetry. The inverse sample setup allows for the easy application of an electrical contact. With this configuration, a centroid wavelength shift of up to 210 nm (Delta lambda/lambda approximate to 25%) within less than 3 min can be achieved, which is extraordinarily large. The resonance shift can be reversed, and the response increases with every voltage cycle, which is attributed to structural changes on the copper surface, leading to an increased surface area.