Highly Transparent and Stable Flexible Electrodes Based on MgO/AgNW Nanocomposites for Transparent Heating Applications

Abstract

Transparent electrodes (TE) based on silver nanowire (AgNW) exhibit good physical properties and constitute a promising alternative to transparent conductive oxides due to their low cost, flexibility, and low toxicity. Nevertheless, they suffer from stability issues over harsh conditions, and encapsulation allows to overcome these limitations. Herein, the low‐cost, scalable fabrication and study of transparent electrodes based on sprayed AgNW networks coated with MgO thin films deposited by atmospheric pressure spatial atomic layer deposition (AP‐SALD) at mild deposition temperature (≤220 °C) is reported. Fabrication of MgO thin films by AP‐SALD is reported here for the first time, and their deposition on different substrates is optimized. MgO exhibits a pure phase and conformal growth with a preferential (220) crystalline orientation and a higher growth rate as compared to conventional atomic layer deposition (ALD). Furthermore, thanks to the conformal coating of MgO on AgNW, the obtained nanocomposites exhibit great optical transparency of ≈85% and flexibility while maintaining high stability under thermal and electrical stress. Indeed, this study shows a clear enhancement of the stability of AgNW networks for thin MgO coatings of only a few nanometers thick. Finally, a proof‐of‐concept transparent heater is fabricated to melt a piece of cheese.

Heat-induced morphological changes in silver nanowires deposited on a patterned silicon substrate

“…However, further temperature increases may cause NWs to split into shorter fragments -a process often attributed to Rayleigh instability and energy minimization via spheroidization [28,31]. It has been demonstrated that various coatings can effectively protect metallic NWs by suppressing surface diffusion [32][33][34].…”