Chemical Engineering of Cu–Sn Disordered Network Metamaterials

Abstract

The design and fabrication of large-area metamaterials is an ongoing challenge. In the present work, we propose a scalable design route and low-footprint strategy for the production of large-area, frequency-selective Cu–Sn disordered network metamaterials with quasi-perfect absorption. The nanoscale networks combine the robustness of disordered systems with the broad-band optical response known from connected wire-mesh metamaterials. Using experiments and simulations, we show how frequency-selective absorption in the networks can be designed and controlled. We observe a linear dependence of the optical response as a function of Sn content ranging from the near-infrared to the visible region. The absorbing state exhibits strong sensitivity to both changes in the global network topology and the chemistry of the network. We probe the plasmonic response of these nanometric networks by electron energy loss spectroscopy (EELS), where we resolve extremely confined gap surface-plasmon (GSP) modes.

Targeted Additive Micromodulation of Grain Size in Nanocrystalline Copper Nanostructures by Electrohydrodynamic Redox 3D Printing

“…[39][40][41] Yet, the porosity and its length scales are not as uniform and wellcontrolled as for example in dealloyed nanoporous metals. [42] Thus, more detailed study of the evolution and manipulation of the porosity would be needed to exploit these microstructural features. Of primary interest to the present study are the origins of the transition from small to large grains upon an increase in printing voltage by just a few volts.…”

Strong Coupling in Two‐Phase Metamaterials Fabricated by Sequential Self‐Assembly

“…By selecting two specific self‐assembly reactions, namely phase separation and chemical dealloying, a two‐phase metamaterial consisting of a disordered Cu network metamaterial and Sn nanoparticles has been manufactured. Engineering of the size and shape of the nanoparticles and the network [ 43 ] is readily achieved by altering the deposition parameters. Thereby, the self‐organization during growth provides a versatile mechanism to modify the plasmonic response of the nanoparticle phase.…”

“…The spectra of plasmonic eigenmodes measured in different "hot-spots" of the network are quasi identical, suggesting that the network provides a means for energy equipartition. Previous experimental works [42,43] studying similar networks in the context of perfect absorbers, imply that a significant fraction of these plasmonic eigenmodes are accessible from the far field.…”

Strain‐Driven Thermal and Optical Instability in Silver/Amorphous‐Silicon Hyperbolic Metamaterials

“…[56] An interesting approach to overcome this limitation is to use natural hyperbolic materials, which derive their optical anisotropy from their crystal structure. [8,57] Other approaches to limit elastic strain driven degradation include geometrical designs beyond multilayers limiting the contact area with the surface [18,58,59] or substrate engineering aiming to reduce the CTE mismatch between the HMM and the substrate. [60]…”