Improving the Conductivity and Stability of Silver Nanowires Through Spontaneous Ligand Exchange for Joule Heating

Silver nanowires (AgNWs) are promising materials for optoelectronic devices, owing to their high transparency and conductivity. However, their performance is limited by polyvinylpyrrolidone (PVP) as an insulating capping agent that is essential for the synthesis of AgNWs but increases their intrinsic resistance. Herein, we introduce a facile spin-coating ligand exchange strategy that considers the physicochemical properties of ligands, including PVP solubility, viscosity, volatility, and hydrogen-bonding ability, to achieve a stable adsorption and efficient exchange. Among the tested ligands, ethylene glycol (EG) ligand effectively reduces the intrinsic resistance and enhances the optoelectronic properties of AgNWs by spontaneously replacing PVP and forming a stable EG⋯PVP hydrogen-bonded complex, as confirmed by multiple analysis methods. The ligand exchanged AgNWs electrode (AgNWs-EG) improves both in-plane and out-of-plane carrier transport properties as well as stability. Leveraging these properties, AgNWs-EG exhibits a 35% increase in Joule heating performance compared to the pristine AgNWs electrode and remarkable stability at elevated temperatures around 120 °C. Moreover, the performance of AgNWs-EG can be further enhanced through their combination with MXene.