Flexible and stretchable transparent conductive graphene-based electrodes for emerging wearable electronics

With the emergence and rapid development of smart wearable electronics, urgent demands for flexible and stretchable transparent conductive electrodes (TCEs) have attracted tremendous attentions to replace the conventional bulky and brittle indium tin oxide. As a novel two-dimensional carbon material with single atomically layer thickness, graphene is considered as an ideal candidate for elastic TCEs due to its distinct properties, such as excellent electrical conductivity, high light transparency, outstanding mechanical flexibility, as well as remarkable chemical/thermal stability. Graphene-based elastic TCEs exhibit promising prospects in wearable electronics such as foldable touch screens, epidermal sensors, soft light-emitting diodes, bendable solar cells, as well as deformable energy conversion/storage devices. This review comprehensively summarizes the state-of-the-art advancements on graphene-based elastic TCEs, including graphene synthesis, electrode fabrication, optoelectronic property, modifications, flexible and stretchable structure design, and smart wearable applications. We focus on advanced graphene-based elastic TCEs which could exhibit excellent electrical conductivity and high light transparency simultaneously while under large mechanical deformations, and discuss the strategies and mechanisms that suitable for fabricating TCEs with high mechanical flexibility and stretchability. Finally, critical consideration on the opportunities and challenges of graphene-based flexible and stretchable TCEs towards practical wearable applications are also presented.