Polymer-Passivated\nSilver Nanowire Transparent Electrodes\nin Flexible PEDOT:PSS-Based Electrochromic Devices

Abstract

Silver nanowire networks are a promising replacement\nto indium\ntin oxide as transparent electrodes, which are necessary components\nof electrochromic devices. However, silver nanowires suffer from a\nshort lifetime due to silver corrosion. Unlike many nanowire electrode\npassivation materials studied in the literature, the current work\nfocuses on an inexpensive nonconductive passivation layer, allowing\nthe utilization of transparent polymers. Herein, a coating of a thin\nlayer of polyurethane (PU) was used to prevent corrosion and to limit\nthe electrode sheet resistance to an increase of only 1.8× after\n6 months. PU is cheap and easy to deposit, 96% transparent across\nthe visible and NIR regions (Atkinson, J. “Silver Nanowire\nNetworks in Electrochromic Devices”, Thesis, University of\nWaterloo, Waterloo, 2023), increases the mechanical flexibility of\nnanowire electrodes, improves nanowire adhesion, and decreases surface\nroughness by an average of 15 nm. The PU-passivated nanowire electrodes\nare integrated into mechanically flexible symmetric PEDOT:PSS-based\nelectrochromic displays. Compared to similar devices based on ITO\nelectrodes, the PU-passivated nanowire-based devices show higher color\nmodulation, shorter switching times, a larger change in reflectance\nin the visible properties, and a longer lifetime. Most noteworthy\nare their far superior mechanical properties. After 50 bending cycles,\nthe nanowire-based devices had little change in performance, whereas\nITO-based devices no longer worked.