Synergism of Cl− and Br− on the controllable synthesis of flexible silver nanowires

• Published in: Inorganic chemistry communications Vol. 158; p. 111451
• Main Authors: Li, Jiayi, Zhang, Hengtong, Yang, Hongcai, Lin, Shudong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2023
• Subjects: Controllable synthesis; FeCl3; Flexible silver nanowires; Growth mechanism; KBr; FeCl3; KBr; Flexible silver nanowires; Controllable synthesis; Growth mechanism
• ISSN: 1387-7003
• DOI: 10.1016/j.inoche.2023.111451

Based on the simple one-pot method and the principle of alcohol thermal reduction, we have innovatively developed a method for the synthesis of highly pure flexible AgNWs with an average diameter of 25–35 nm and length of 35–45 μm. The effects of different proportions of Cl− and Br− on the morphology of AgNWs were systematically studied, the growth mechanisms of flexible AgNWs were explored, and the formation mechanism of flexible AgNWs was analyzed. Herein, it was found that the formation of flexible AgNWs may be due to the electrostatic repulsion and external forces between the particles during the formation of AgNWs, which formed the binding sites of AgCl-PVP-NO3− and AgBr-PVP-NO3−, thereby promoting the crystal nucleus to continuously generate flexible AgNWs. In the process of synthesizing silver nanowires, the additives FeCl3 and KBr can play a synergistic role in regulating the morphology of silver nanowires. This method can prepare high-quality flexible AgNWs, which provides theoretical and technical support for its application in areas such as catalysis and optoelectronic devices. [Display omitted] •High-purity and flexible silver nanowires were controllable synthesized by simultaneously adding FeCl3 and KBr.•The morphology of silver nanowires regulated through the synergistic effect of Cl− and Br− was fully discussed.•The strong polarization effect caused by Br− in the reaction makes the grain growth subject to the dual effects of electrostatic repulsion and external forces, resulting in the formation of flexible and soft silver nanowires. Silver nanowires (AgNWs) exhibit excellent electrical conductivity and hold significant potential for usage in flexible electronics. AgNs can possess a suitable aspect ratio, uniformity, and flexibility that are essential for achieving high-performance flexible transparent conductive films. However, the synthesis of AgNWs presents a challenge in controlling its morphology, often resulting in varying lengths and aspect ratios that are difficult to regulate. Thus, the controlled preparation of AgNWs holds great significance. Herein, AgNWs were synthesized via a polyol method with FeCl3 and KBr composite metal salt as control agents, silver nitrate as a silver source, ethylene glycol as a reducing agent and solvent, and polyvinylpyrrolidone (PVP) as a growth director. By adjusting the ratio and dosage of FeCl3 and KBr, the morphology controllability of AgNWs was realized, and the obtained AgNWs can be straight or bendable. The surface morphology and microstructure of the AgNWs were analyzed by scanning electron microscopy (SEM). Due to the synergistic effect of FeCl3 and KBr, flexible AgNWs with an average diameter of 25–35 nm, an average length of 35–45 um, and an aspect ratio of over 1000 can be obtained. Mechanism studies have shown that through electrostatic interactions, AgCl, AgBr, NO3−, and PVP in the reaction mixture can form binding sites for AgCl-PVP-NO3− and AgBr-PVP-NO3−, thus causing the silver nanowires to become flexible. Meanwhile, the strong polarization effect caused by Br− in the reaction causes the chain growth to become subject to the dual effects of electrostatic repulsion and external forces, resulting in the formation of flexible and soft silver nanowires.