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

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 degrees 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 approximate to 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. MgO thin films are deposited for the first time using Spatial Atomic Layer Deposition at low-temperature. Transparent electrodes made of Silver nanowire (AgNW) networks coated with MgO thin films several nm thick show enhanced stability even after bending. The composites are tested as transparent heaters.image

Automated summary

This study reports a low-cost and scalable fabrication method for transparent electrodes based on sprayed AgNW networks coated with MgO thin films deposited by AP-SALD at mild deposition temperature (<= 220 degrees C). The study also presents the first reported method for fabricating MgO thin films by AP-SALD and optimization of their deposition on different substrates. The resulting nanocomposites exhibit high stability under thermal and electrical stress while maintaining approximately 85% optical transparency, thanks to the conformal coating of MgO on AgNW.