Enhanced Durability and Antireflective Performance of Ag-Based Transparent Conductors Achieved via Controlled N-Doping

Abstract

Ag-based transparent conductors (TCs) are often proposed as an alternative to ITO coatings. However, while their performance has been widely demonstrated, their environmental durability is frequently overlooked or addressed with the use of highly specific encapsulating layers. In this work, the durability and antireflective performance of Ag-based TCs are simultaneously enhanced. To do so, a transfer matrix modeling approach is used to determine the general requirements for high performance antireflective properties as a function of Ag thickness and dielectric refractive indices, offering more widely applicable insight into stack optimization. Coating durability is investigated as a function of the Ag microstructure, which is modified by altering the N 2 concentration used for doping of the Ag layer and the selection of the seed layer. Increasing N 2 concentration during Ag deposition was found to decrease grain size and durability of Ag coatings deposited on Si 3 N 4 whereas all coatings on ZnO (Al) showed higher stability. Significantly higher durability is found when specifically combining intermediate N 2 concentrations in the sputtering gas mixture (Ag (N) :5%, compared to 0% and 50%) and a ZnO (Al) seed layer, and a mechanism accounting for this increased durability is proposed. The addition of NiCrN x protective coatings increases the system durability without altering these trends. These findings are combined to fabricate a highly performant Ag-based TC (T V = 89.2%, R V FS = 0.23%, 21.4 Ω), which shows minimal property changes following corrosion testing by immersion in a heated and highly concentrated aqueous NaCl solution (200 g/L, 50 °C).