The refractive index of silver nanowire networks: a heuristic approach to the foundations of the optical constants, from experiment to theory

This study employs Mie's scattering theory and van de Hulst's mixing model to predict the refractive indices (n, k) of silver nanowire (AgNW) networks in the visible and near-infrared wavelengths, allowing the comparison to the experimentally determined k spectra. Transmittance spectra calculated via the numerical resolution of Fresnel's equations are compared to experimental data, showing excellent agreement, particularly for nanowires with larger diameters and at shorter wavelengths. These findings, both theoretical and empirical, pave the way for accurate optical simulations of metallic nanowire networks, supporting their integration into complex multilayer systems and devices such as displays or smart windows. Notably, our work proposes the first demonstration of the dominance of the metallic character of AgNW networks over their dielectric behavior in terms of optical response.