Silver Nanowire Networks Coated with a Few Nanometer Thick Aluminum Nitride Films for Ultra-Transparent and Robust Heating Applications

Transparent electrodes based on emerging nanomaterials like silver nanowire (AgNW) networks have been extensively investigated in the past few years. Thanks to their superior flexibility and versatility in terms of fabrication and device integration, they present an excellent alternative to indium tin oxide. However, the lack of thermal, electrical, and chemical stability requires the encapsulation of the AgNW. This has been performed using thin metal oxide films, graphene, or organic protective coatings. Despite the very promising properties of such nanocomposite approaches and the performance enhancement, more investigation is needed to minimize the loss of optical transmittance upon coating and achieve superior electrical, thermal, and mechanical stability. In the present work, the encapsulation of AgNW networks with aluminum nitride (AlN) coatings is reported for the first time, and it is compared to AgNW/Al2O3 nanocomposites. Thanks to the low thicknesses (<20 nm) and the wide band gap of AlN, the optical transparency is not impacted. Furthermore, the nanocomposite networks demonstrate no failure under electrical and thermal stress conditions (up to 21 V and 400 °C respectively), in contrast to the AgNW/Al2O3 nanocomposites, which fail after 15 V and 350 °C. In addition, microscratch tests reveal the remarkable mechanical robustness of the nanocomposites, and the electrical stability is further confirmed under accelerated environmental tests, coupled with ex situ characterization by SEM and XPS. The results reported in the present work show that AgNW/AlN electrodes are outstanding candidates for high-performance transparent electrodes.