Highly Flexible and Transparent Ag Nanowire Electrode Encapsulated with Ultra-Thin Al₂O₃: Thermal, Ambient, and...

There is an increasing demand in the flexible electronics industry for highly robust flexible/transparent conductors that can withstand high temperatures and corrosive environments. In this work, outstanding thermal and ambient stability is demonstrated for a highly transparent Ag nanowire electrode with a low electrical resistivity, by encapsulating it with an ultra-thin Al₂O₃ film (around 5.3 nm) via low-temperature (100 °C) atomic layer deposition. The Al₂O₃-encapsulated Ag nanowire (Al₂O₃/Ag) electrodes are stable even after annealing at 380 °C for 100 min and maintain their electrical and optical properties. The Al₂O₃ encapsulation layer also effectively blocks the permeation of H₂O molecules and thereby enhances the ambient stability to greater than 1,080 h in an atmosphere with a relative humidity of 85% at 85 °C. Results from the cyclic bending test of up to 500,000 cycles (under an effective strain of 2.5%) confirm that the Al₂O₃/Ag nanowire electrode has a superior mechanical reliability to that of the conventional indium tin oxide film electrode. Moreover, the Al₂O₃ encapsulation significantly improves the mechanical durability of the Ag nanowire electrode, as confirmed by performing wiping tests using isopropyl alcohol.