Plasma Cleaning and Self-Limited Welding of Silver Nanowire Films for Flexible Transparent Conductors

Silver nanowire (Ag NW) films are the promising next-generation flexible, transparent conductors, but their transport properties are greatly deteriorated by the insulating polyvinylpyrrolidone (PVP) layer wrapping on the Ag NWs. Herein, we report a plasma treatment strategy to completely remove the PVP layer and meanwhile limitedly weld the Ag NW film at the NW/NW junctions to improve the film's carrier transport properties while not affecting its transparency. Particularly, we found that the dual functions of the removal of the PVP layer and self-limited welding can be achieved for a series of commonly used plasmas, e.g., O-2 plasma, H-2-Ar plasma (1:9 in volume), and N-2 plasma. Theoretical simulations reveal that the self-limited welding is caused by the focusing of light (emitted during plasma generation) at the NW/NW junctions, which thermally activates silver atoms and drives recrystallization therein. With a cleaned surface and welded nature, the plasma-treated Ag NW film shows largely improved conductivity and high flexibility, greatly facilitating its application as a high-performance flexible transparent heater (cycling stability, >40 cycles of heating/cooling; temperature rising rate, 112 degrees C within 30 s at 8 V). Moreover, the plasma-treated Ag NW can also serve as a basic electrode for a stacked electron-only device of Ag NW film/8-hydroxyquinoline/Ag electrode, improving its current collection efficiency by 5.47 times. These results suggest that plasma treatment can greatly benefit the applications of Ag NW film.

Automated summary

Plasma treatment has been shown to be an effective strategy for removing the insulating PVP layer from silver nanowire films and self-limited welding the NW/NW junctions, resulting in improved carrier transport properties without affecting transparency. The plasma-treated Ag NW film exhibited significantly enhanced conductivity and flexibility, making it suitable for applications such as high-performance flexible transparent heaters. Additionally, the plasma-treated Ag NW also demonstrated potential as a basic electrode in electron-only devices, significantly improving current collection efficiency.