Silver nanowires (Ag NWs) with a small diameter of 20 nm and an aspect ratio of 1000 were successfully synthesized using the polyol method in the presence of a magnetic ionic liquid (MIL). The MIL used was 1-butyl-3-methylimidazolium tetrachloroferrate (bmim[FeCl4]), which served as a soft template and ionic salt. Wire formation was highly dependent on the content of bmim[FeCl4], and the diameters of Ag NWs produced in this process can be effectively controlled by adjusting the concentration of 1-butyl-3-methylimidazolium bromide. Self-assembled local structures in MILs are likely to act as soft-templates for highly organized Ag nanostructures. Selective precipitation was used to purify the Ag NWs obtained. The transparent electrode films exhibited the highest optoelectronic performance, with a transmittance of 91%, low haze value of 1.5%, and low sheet resistance of 15 Ω sq−1. These results reveal that the produced Ag NWs performed better than conventional indium tin oxide film.
