Electrochemical control and the use of electrodeposition in the design of dynamic plasmonics have attracted much attention in recent years.¹ Development of dynamic plasmonic metamaterials is attractive for many applications such as molecular sensing and analysis, environmental monitoring, photo-catalysis, colour changing displays and electrochromic devices such as 'smart' windows. Electrodeposition is one of the most attractive ways to create and reversibly transform nanostructures' shape, size and chemical composition.^2,3

Plasmonics is related to the localised surface excitations of electrons in metal nanostructures due to strong interactions with light. The resulted electric field enhancement due to the surface plasmons can be used to manipulate light–matter. Nanostructured Ag and Au are classic plasmonic materials. While silver is a metal that exhibits many advantages over gold, such as higher extinction coefficients in the blue and UV region of the EM spectrum, sharper extinction bands and extremely high field enhancements, its employment is hindered by low chemical stability. The most recent theoretical analysis suggests that Au-Ag derived nanostructures with controlled geometry, composition, and distribution can create new interesting optical phenomena.⁴ By developing Au-Ag based nanostructures, we can then benefit from combining optical properties of Au and Ag and, at the same time, improve the chemical stability of silver.

We investigated the electrodeposition of Au and Ag-based arrays of ordered and random nano-particles on indium tin oxide substrates from different solutions and studied their optical properties. We demonstrated that varying the electrodeposition parameters led to changes in both the resonance wavelength and the strength of resonance linked to the structural characteristics (size and shape) and the chemical composition of the deposited particles. Exploration of the dynamic reversible changes via electrodeposition will be presented.

References:

1. Y. Jin, L. Zhou, J. Liang, and J. Zhu, Adv. Photon., 3(4), 044002 (2021).
2. G. Wang, X. Chen, S. Liu, C. Wong, S. Chu, ACS Nano, 10 (2), 1788–1794, (2016)
3. C. J. Barile, D. J. Slotcavage, J. Hou, M. T. Strand, T. S. Hernandez, M. D. McGehee, Joule 1 (1), 133-145 (2017)
4. G. Guisbiers, R. Mendoza-Cruz, L. Bazan-Diaz, J. J. Velazquez-Salazar, R. Mendoza-Perez, J. A. Robledo-Torres, J. L. Rodriguez-Lopez, J. M. Montejano-Carrizales, R. L. Whetten, Jose-Yacaman, M. ACS Nano, 10(1), 188-198, (2016)