Interface engineering of solution-grown silver nanofiber networks designed as flexible transparent electrodes

Abstract

Metal nanonetworks fabricated by chemical plating of metals on electrospun polymer nanofiber network templates have come into the spotlight for use as flexible transparent electrodes. However, depositing continuous and smooth metal films on hydrophobic polymer nanofiber templates is difficult because of the Volmer–Weber growth of metals. This work reports a simple argon plasma treatment approach to increase the surface energy of the templates and achieve the formation of dense silver layers. Furthermore, instead of using external treatment methods that either require high energy injection or are incompatible with plastic substrates, a low-temperature Joule heat-assisted self-welding method is used to improve the conductivity of the solution-grown Ag nanofibers. Instantaneous Joule heat generated by a direct current can target the high-resistance interfaces formed between the Ag nanoparticles and at the grain boundaries, thus lowering the junction resistance and decreasing the interface scattering. The resulting Ag nanofiber networks exhibit high visible light transmittance of ∼91%, low sheet resistance of ∼5.4 Ω □⁻¹, and good stretchability. These results offer valuable insight into the abilities of plasma treatment and Joule heating to modulate the metal film formation mode on polymer nanofiber surfaces. These interface engineering methods can be extended to the development of polycrystalline metal nanonetwork-based electronics.