Abstract :
[en] Metallic nanowire networks have emerged as key building blocks for next-generation
functional materials, notably as flexible and transparent conductors and as
reconfigurable elements for neuromorphic devices. Among them, silver nanowire
(AgNW) networks combine high optical transparency, low electrical resistance,
mechanical flexibility, and solution-processable fabrication. Beyond their functional
advantages, however, the long-term stability of AgNW networks under electrical
operation remains a critical challenge, intrinsically linked to their nanometric
dimensions and high surface-to-volume ratio.
At these length scales, atomic migration cannot be treated as a negligible
perturbation as even modest atomic fluxes may induce substantial morphological
changes. Such migration processes may be driven by a variety of coupled physical
and chemical constraints, including temperature, concentration and mechanical
stress gradients, external fields, or changes in chemical state. In this context,
electrical stressing under ambient conditions activates a complex interplay of
degradation mechanisms. While macroscopic AgNW films are often described using
simplified models dominated by Joule heating, and single-nanowire studies typically
isolate a single failure pathway, the intermediate regime between these two limits
has remained largely unexplored.
In this work, we investigate the electrical failure of micrometer-sized AgNW networks
composed of a few to a few tens of nanowires, subjected to controlled pulsed
electrical stresses. This intermediate scale provides a minimal yet representative
model system that captures the onset of collective degradation phenomena while
remaining experimentally tractable. Because the entire network fits within a single
high-resolution microscopy field of view, every individual breakdown event can be
detected, spatially localized, and temporally ordered. This exhaustive mapping of
failure pathways removes ambiguities associated with statistical averaging in large
networks and enables a direct correlation between local topology, current
distribution, and degradation dynamics.
The reduced network size further allows a high-fidelity reconstruction of the
experimental topology at the individual segment level, paving the way for accurate
digital-twin simulations of electrically stressed nanowire networks. In addition, we
employ scanning laser microscopy to probe and visualize the percolation pathways
within AgNW networks. To the authors’ knowledge, this work constitutes the first
demonstration of this technique as a tool for mapping current-carrying pathways and
failure dynamics in metallic nanowire networks.
