Recent advances in flexible/stretchable sensors using laser-induced three-dimensional porous graphene: From precursor to manufacturing

Graphene is an ideal material for flexible sensors with outstanding stretchability and extensibility, but its further development is being severely hindered by the existing multi-step routes. Laser-induced graphene (LIG) is a recently emerging technology that enables industrial scale preparation with mask-free, fast-scanning speed, and high spatial resolution. In this review, the latest advances on three-dimensional porous LIG from the perspective of precursor selections to manufacturing methods are presented. First, the commonly precursors such as graphene oxide, polymers, and natural materials for photothermal/chemical transformation was classified in combined with auxiliary processing equipment. Then, three all-purpose fabrication strategies, including castingand-peeling transfer, topology architecture and Kirigami design, are summarized for the LIG-based sensors. Next, the representative progress of flexible/stretchable LIG-based pressure, strain, liquid, and gas sensors were categorized based on sensing principles, with the aim of improving the sensing performance in practical applications. Finally, the newest developments, major challenges, and outlook in LIG-manufacturing and integrated flexible sensors are discussed, showing huge potential in future wearable electronics.