Rapid and Facile Synthesis of High-Performance Silver Nanowires by A Halide-Mediated, Modified Polyol Method for Transparent Conductive Films

Continuous flow synthesis of metal nanowires: protocols, engineering aspects of scale-up and applications

This review comprehensively covers the translation from batch to continuous flow synthesis of metal nanowires (i.e., silver, copper, gold, and platinum nanowires) and their diverse applications across various sectors. Metal nanowires have attracted significant attention owing to their versatility and feasibility for large-scale synthesis. The efficacy of flow chemistry in nanomaterial synthesis has been extensively demonstrated over the past few decades. Continuous flow synthesis offers scalability, high throughput screening, and robust and reproducible synthesis procedures, making it a promising technology. Silver nanowires, widely used in flexible electronics, transparent conductive films, and sensors, have benefited from advancements in continuous flow synthesis aimed at achieving high aspect ratios and uniform diameters, though challenges in preventing agglomeration during large-scale production remain. Copper nanowires, considered as a cost-effective alternative to silver nanowires for conductive materials, have benefited from continuous flow synthesis methods that minimize oxidation and enhance stability, yet scaling up these processes requires precise control of reducing environments and copper ion concentration. A critical evaluation of various metal nanowire ink formulations is conducted, aiming to identify formulations that exhibit superior properties with lower metal solid content. This study delves into the intricacies of continuous flow synthesis methods for metal nanowires, emphasizing the exploration of engineering considerations essential for the design of continuous flow reactors. Furthermore, challenges associated with large-scale synthesis are addressed, highlighting the process-related issues.

Preparation of silver nanowires with controlled parameters for conductive transparent electrodes

Silver nanowires (AgNWs) have excellent flexibility, unique optical transmittance and high conductivity. The polyol process is appropriate for preparing AgNWs due to its simplicity, effectiveness, low cost, and high yield. This work aims to investigate the effect of preparation parameters of the polyol process on the silver nanowires properties. The parameters include the controlling agent, molecular weight of the polyvinylpyrrolidone (PVP), the temperature, and the reducing agent. The amount of silver nanoparticles formed during preparation was used to determine the optimum preparation conditions. The transmission electron microscope (TEM) images showed minimal amount of Ag nanoparticles when using mixed molecular weight of PVP-40K, and PVP-1.3M at 150 °C with the assistance of copper chloride as a controlling agent. The prepared AgNWs had an average length of 3.7 µm and aspect ratio of 15.3. The fabricated electrodes were characterized using a scanning electron microscope (SEM) and four probe resistivity measurements. The electrical measurement of the AgNWs electrodes indicated that the surfactant thickness is a critical parameter in having low sheet resistance electrodes. Also, the optical transmission was affected by the amount of nanoparticles. The prepared electrode with high concentration of AgNWs and a minimal amount of nanoparticles exhibited 80% optical transmission.

Fabrication of composite transparent conductive electrodes based on silver nanowires

Composite transparent conductive electrodes (C-TCEs) have recently been produced using low-cost techniques to keep up with the boom in the fabrication and development of optoelectronic devices. In this article, silver nanowires (AgNWs) were successfully synthesized by a simple hydrothermal method using different molecular weights MWs of poly (N-vinylpyrrolidone) (PVP). Graphene oxide (GO) was prepared using the modified Hummers' method and a reduction step was held on GO films to produce reduced GO (rGO). C-TCEs were fabricated by over-coating the AgNWs electrodes with rGO, or poly(3,4-ethylenedioxythiophene) polystyrene sulfonate to improve the roughness, surface energy, and sheet resistance. The influence of using lower and higher MWs of PVP on the yield, shape, and size of AgNWs was investigated. The results showed that using lower MW of PVP had a great effect on the yield, morphology, and aspect ratio of AgNWs with diameter of 46 nm and average length 12 µm. The optical, morphological, topographical, and electrical properties of TCEs were studied. AgNWs/rGO composite electrode provided the lowest surface roughness and surface energy of 250 nm and 47.95 mN/m, respectively, with a relatively high transparency of 78.2% at 550 nm light wavelength, and a low sheet resistance of 27 Ω/□.

Graphene-Based Composites with Silver Nanowires for Electronic Applications

Graphene/metal nanocomposites have shown a strong potential for use in electronic applications. In particular, the combination of silver nanowires (AgNWs) with graphene derivatives leads to the formation of an efficient conductive network, thus improving the electrical properties of a composite. This work focused on developing highly conductive hydrophilic hybrids of simultaneously functionalized and reduced graphene oxide (f-rGO) and AgNWs in different weight ratios by following two different synthetic routes: (a) the physical mixture of f-rGO and AgNWs, and (b) the in situ reduction of GO in the presence of AgNWs. In addition, the role of AgNWs in improving the electrical properties of graphene derivatives was further examined by mixing AgNWs with a hybrid of few-layered graphene with functionalized multiwalled carbon nanotubes (FLG/MWNT-f-OH). The studied materials showed a remarkable improvement in the overall electrical conductivity due to the synergistic effect of their components, which was proportional to the percentage of Ag and dependent on the procedure of the hybrid formation. One of the f-rGO/AgNWs composites was also selected for the preparation of gravure printing inks that were tested to determine their rheological and printing properties. All of the f-rGO/AgNWs composites were shown to be very promising materials for use as conductive inks for flexible electronics.