Unraveling the solvent induced welding of silver nanowires for high performance flexible transparent electrodes

Abstract

A solution processed metal nanowire network is a promising flexible transparent electrode to replace brittle metal oxides for printable optoelectronics applications, but suffers from the issue of pseudo contact between nanowires. Herein, using volatile solvent mists as a powerful "zipper", we demonstrate a simple and rapid method to effectively weld silver nanowires, which dramatically improves the conductivity and robustness of the silver nanowire network based flexible transparent electrodes. We reveal that for a stacked network structure, the unique wedge-shaped nanogaps between the long nanowires and substrate provide a strong capillary force during solvent evaporation, which is much larger than that between zero-dimensional nanoparticles and gives a decisive contribution for nanowire junction welding, and this nanowire-substrate interplay force is positively related to the wettability of the substrate. At the same time, the dissolution-reprecipitation of the capping agent on the silver nanowire surface as the natural adhesive can fix the network on the substrate tightly, which enhances the robustness of the network. Our approach solves two key issues in solution-processed transparent electrodes in one simple step, and is compatible with various mild solution-processed optoelectronic devices, especially those containing heat-sensitive or chemical-sensitive materials. Moreover, a new type of invisible infrared encryption display is demonstrated based on this approach.

Ultrastretchable Hybrid Electrodes of Silver Nanowires and Multiwalled Carbon Nanotubes Realized by Capillary‐Force‐Induced Welding

“…It is believed that the cold welding of AgNWs relies on the capillary force induced by the water droplets filling in the NW–NW gaps. During water evaporation, the capillary force drives the separate AgNWs to contact and fuse . To clarify if the capillary force could induce the welding of AgNWs and CNTs, we estimated and compared the values of capillary force between the building blocks.…”

“…−1 after moisture treatment for seconds . This simple, low‐cost, rapid, and room‐temperature pathway is highly suitable for the fabrication of SCMs 9c,10,11. On the other hand, carbon nanotubes (CNTs), also a typical 1D nanomaterial, have been recently composited with AgNW electrodes to enhance the overall performance, mainly the stretchability, as SCMs .…”

Silver nanowire/nickel hydroxide nanosheet composite for a transparent electrode and all-solid-state supercapacitor

“…a small amount of solution (20 mL) is used for each coating. During the water evaporation process, the capillary-force, as a pull force, can bridge the separated NWs 19. Thus both mechanical nanopressing from the Ni(OH) 2 NSs and the coldwelding during water evaporation should be responsible for the strengthened NW contacts and enhanced conductivity.…”

Desolvation‐Triggered Versatile Transfer‐Printing of Pure BN Films with Thermal–Optical Dual Functionality

“…During the desolvation process, capillary force and van der Waals interaction between the substrate and the BN layer drive the BN layer from the membrane onto the substrate. [ 39 ] Because DIAS is based on van der Waals interactions, transfer‐printing of BN is possible even onto chemically inert surfaces such as gold (Figure 1d).…”