Laser-induced direct graphene patterning: from formation mechanism to flexible applications

Laser-induced graphene (LIG), which is directly fabricated by laser carbonization of polymers, has gained much attention in recent years since its first discovery in 2014. Specifically, featuring native porosity, good mechanical properties, and excellent electrical/electrochemical properties, it is considered a promising material for flexible electronic devices. Meantime, LIG can be processed in the atmosphere within a few seconds, thereby significantly reducing the fabrication cost of graphene. Facilitated by these features, this methodology has received great development with worldwide efforts in the following years, including the formation mechanism of LIG, the diversity of laser sources (from infrared laser to ultraviolet laser), the diversity of carbon sources (thermoset polymers, thermoplastic polymers, and natural polymers), and property modulation of LIG (porosity, electrical property, hydrophilic/hydrophobic property, electrochemical property), along with the broad applications of LIG in various flexible electronic devices. Here, the recent advances in the mechanism studies and preparation methods of LIG are comprehensively summarized. The various technologies for the modification of LIG are reviewed. A thorough overview of typical LIG-based flexible electronic devices is presented. Finally, the current challenges and future directions are discussed