Mixed polyvinyl pyrrolidone hydrogel-mediated synthesis of high-quality Ag nanowires for high-performance transparent conductors†
Silver nanowires (Ag NWs) are promising building blocks for next-generation flexible transparent conductors (TCs). However, the current industrial synthesis method for Ag NWs, i.e., the polyol reduction method, readily produces abundant byproducts of Ag nanoparticles and leaves an insulating polyvinylpyrrolidone (PVP) layer wrapped around the Ag NWs, thereby deteriorating the optical and carrier transport properties of the resultant Ag NW films, respectively. Herein, we report a novel mixed PVP (m-PVP) hydrogel-mediated polyol reduction method for the synthesis of high-quality Ag NWs with negligible Ag NPs produced, high aspect ratio (exceeding 1200), and a thin (∼1 nm) capping layer. Consequently, the resultant Ag NWs can be directly processed into high-performance TCs, without the need for sophisticated separation and post-treatment processes. Moreover, as a result of the thin capping layer that furnishes only limited resistance to deteriorate the carrier transport properties less, the electron-only device constructed from the m-PVP-wrapped Ag NW film delivers a current collection efficiency 7.7 times that of the device constructed from the conventional PVP-wrapped Ag NW film. The as-developed synthesis method is expected to greatly reduce the fabrication cost and time of Ag NW TCs in a continuous production line.