Three-Step, Seed-Mediated Synthesis of Ultrathin AgNWs in Aqueous Solution

Mass production of ultrathin Ag nanowires (AgNWs) via eco-friendly synthetic methods is crucial for current flexible electronic products. Herein, we reported a three-step, seed-mediated synthesis of ultrathin AgNWs with an average diameter of −17 nm and an aspect ratio of ∼1000 in aqueous solution. Using pentatwinned Au dodecahedrons as the primitive seeds for growing Ag nanorods (AgNRs), ultrathin AgNWs were obtained in the subsequent growth process with AgNRs as the secondary seeds under optimized conditions. Both Au seeds and AgNRs were directly used as seeds without any purifying treatment. High purity AgNWs could be harvested from a simple precipitation process taking advantage of the depletion-induced sediment method. It was found that the one-dimensional growth of AgNRs and AgNWs was mainly determined by the reduction rate in forming Ag0, which could be tuned by varying the molar ratio of AgNO3 to ascorbic acid, the concentrations of NH3·H2O and hexadecyltrimethylammonium bromide, as well as the pH value of the reaction solution. The developed method might be competitive with traditional polyol-based synthesis of ultrathin AgNWs as the reaction condition is much milder and free of a time-consuming purification process.