Large-Scale and Galvanic Replacement Free Synthesis of Cu@Ag Core-Shell Nanowires for Flexible Electronics

Copper nanowires (CuNWs) are considered a promising alternative to indium tin oxide due to their cost-effectiveness as well as high conductivity and transparency. However, the practical applications of copper-based conductors are greatly limited due to their rapid oxidation in atmosphere. Herein, a facile adsorption and decomposition process is developed for galvanic replacement free and large-scale synthesis of highly stable Cu@Ag core-shell nanowires. First, Ag-amine complex ([Ag(NH₂R)₂]⁺) as silver source adsorbs on CuNWs surface, and Cu@Ag-amine complex core-shell structure is formed. After that, Ag-amine complex is easily decomposed to pure Ag shell through a simple thermal annealing under air. By adjusting the concentration of Ag-aminein CuNWs solution, Cu@Ag core-shell nanowires with different thickness of silver shell can be easily obtained. The obtained core-shell nanowires exhibit high stability for at least 500 h at high temperature (140 °C) and high humidity (85 °C, 85% RH) due to the protection of Ag shell. More importantly, the conductivity and transparency of Cu@Ag nanowires-based conductors is similar to that of pure CuNWs. The large-scale and facile synthesis of Cu@Ag core-shell nanowires provides a new method to prepare stable metallic core-shell nanowires.