Bending fatigue behavior of silver nanowire networks with different densities

This study examines the deformation behavior of silver nanowire networks with different densities under bending fatigue testing conditions. Up to 400,000 bending cycles are applied to the various silver nanowire networks while monitoring the resistance in situ. The least dense silver nanowire network shows a moderate decrease in resistance during the early bending cycles due to mechanical welding, followed by a rapid increase as the bending test progresses. As the nanowire density increases, however, this initial decrease in the resistance becomes smaller, and the resistance of the densest silver nanowire network increases sharply from the very start of the cyclic bending. A microstructural analysis reveals that the junction formation by mechanical welding in the early stages of bending is pronounced for the less dense silver nanowire networks, while the densest network showed severe deformation, including broken or disintegrated nanowires due to their confined geometry, which cannot easily accommodate the bending strain by stretching the network. Our findings underscore that different criteria should be considered to evaluate the mechanical reliability of various flexible electronic devices using silver nanowire electrodes with different densities.