Composites of Shellac and Silver Nanowires as Flexible, Biobased, and Corrosion-Resistant Transparent Conductive Electrodes

Abstract

Silver nanowires (AgNWs) are a promising material to replace indium tin oxide as transparent conductive electrodes (TCEs) in next-generation flexible optoelectronics. AgNWs are more environmental friendly than indium tin oxide, and offer solution processability, high conductivity, and high optical transparency. Embedding AgNWs at the surface of a polymer matrix creates a planar, conductive surface that is ideal for use in thin-film devices. However, a barrier to practical use is corrosionin the ambient environment, which damages the AgNW network and reduces the workable life span. This study presents the use of shellac, an eco-friendly natural biopolymer, as a planarizing and protective matrix for AgNWs. Shellac has a long history as a coating due to its excellent film-forming ability and barrier properties, yet it has been largely unexplored in electronics. Here, the first shellac-based TCE comprising a AgNW network embedded at the surface of a shellac matrix is reported. Shellac-AgNW TCEs provide high conductivity and optical transparency, as well as mechanical stability under tensile strain. They also effectively function as TCEs in light-emitting devices. Furthermore, the barrier properties of shellac protect AgNWs from corrosion in humid air and corrosive acid vapors. These results position shellac as a sustainable alternative to persistent synthetic polymers, in flexible electronics.