Solvent Welding-Based Methods Gently and Effectively Enhance the Conductivity of a Silver Nanowire Network

Abstract

To enhance the conductivity of a silver nanowire (Ag NW) network, a facile solvent welding method was developed. Soaking a Ag NW network in ethylene glycol (EG) or alcohol for less than 15 min decreased the resistance about 70%. Further combined solvent processing via a plasmonic welding approach decreased the resistance about 85%. This was achieved by simply exposing the EG-soaked Ag NW network to a low-power blue light (60 mW/cm2). Research results suggest that poly(vinylpyrrolidone) (PVP) dissolution by solvent brings nanowires into closer contact, and this reduced gap distance between nanowires enhances the plasmonic welding effect, hence further decreasing resistance. Aside from this dual combination of methods, a triple combination with Joule heating welding induced by applying a current to the Ag NW network decreased the resistance about 96%. Although conductivity was significantly enhanced, our results showed that the melting at Ag NW junctions was relatively negligible, which indicates that the enhancement in conductivity could be attributed to the removal of PVP layers. Moreover, the approaches were quite gentle so any potential damage to Ag NWs or polymer substrates by overheating (e.g., excessive Joule heating) was avoided entirely, making the approaches suitable for application in devices using heat-sensitive materials.

Introductory Overview of Layer Formation Techniques of Ag Nanowires on Flexible Polymeric Substrates

“…Spray coating is a versatile and cost-effective method for depositing Ag nanowires on both rigid and flexible substrates [14,[36][37][38]. This technique is simple and able to cover large areas uniformly.…”

“…Researchers are exploring novel approaches to optimize the spray parameters, such as the solvent composition and nozzle design, to enhance the homogeneity of the resultant films. In a notable example of these achievements, Zhu et al developed a solvent-welding technique employing Ag nanowire spray coating (Figure 2) [36]. Ag nanowire networks combined with poly(vinylpyrrolidone) (PVP) and camphorquinone were spray coated onto a substrate containing ethylene glycol.…”

“…The versatility of spray-coating in terms of material selection and scalability makes it a valuable solution for wide-ranging applications, from small-scale laboratory research to large-scale industrial manufacturing. The ability to generate uniform and transparent conductive films through spray coating is particularly promising for the advancement of technologies such as flexible displays, touchscreens, and solar cells [14,[36][37][38]. Furthermore, this method is cost-effective for the production of transparent conductive films.…”