Highly Flexible and Transparent Ag Nanowire Electrode Encapsulated with Ultra-Thin Al(2)O(3): Thermal, Ambient, and Mechanical Stabilities

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 Al(2)O(3) film (around 5.3 nm) via low-temperature (100 °C) atomic layer deposition. The Al(2)O(3)-encapsulated Ag nanowire (Al(2)O(3)/Ag) electrodes are stable even after annealing at 380 °C for 100 min and maintain their electrical and optical properties. The Al(2)O(3) encapsulation layer also effectively blocks the permeation of H(2)O 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 Al(2)O(3)/Ag nanowire electrode has a superior mechanical reliability to that of the conventional indium tin oxide film electrode. Moreover, the Al(2)O(3) encapsulation significantly improves the mechanical durability of the Ag nanowire electrode, as confirmed by performing wiping tests using isopropyl alcohol.