Sliding Interconnection for Flexible Electronics with a Solution‐Processed Diffusion Barrier against a Corrosive Liquid Metal

Abstract The epoch of flexible electronics demands new measures to interconnect electronic components and circuits under mechanical deformations such as bending, rolling, folding, and even stretching. Although liquid metal has been proposed as an alternative to solid‐state solder alloys and conductive adhesives, its corrosive nature rapidly deteriorates the electrical and structural integrity of metallic interconnects and has remained an arduous challenge. A facile solution‐processable method to construct a flexible and electrically conductive diffusion barrier on aluminum electrodes, which are vulnerable to liquid metal, is presented. The stacked layers of graphene oxide (GO) in conjunction with poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) effectively block the diffusion of liquid metal, where PEDOT:PSS serves as an electrically conducting medium to complement the non‐conductive trait of GO, and as an impeding factor together with GO against the diffusion of liquid metal. A fluidic interconnect using liquid metal and aluminum electrodes with the solution‐processed diffusion barrier of the PEDOT:PSS/GO composite exhibits a better electrical contact property than a conventional interconnect. Finally, a novel proof of concept of sliding interconnection is demonstrated by rolling a carbon nanofiber‐coated liquid metal ball on aluminum electrodes coated with the PEDOT:PSS/GO composite, offering a new opportunity beyond flexibility and stretchability.