Laser-induced graphene for micro- and nano-manufacturing: fundamentals, processing approaches, and emerging applications

Laser-induced graphene (LIG) has emerged as a promising manufacturing strategy for flexible and multifunctional electronics because it enables direct, lithography-free conversion of carbon-rich precursors into porous conductive graphene under ambient conditions. Compared with conventional graphene synthesis methods, which often require high temperatures, vacuum systems, multistep processing, or hazardous chemicals, LIG offers a simpler and potentially more sustainable route compatible with diverse substrates, including polyimide, lignin-containing biomass, textiles, and other unconventional materials. This review summarizes recent advances in LIG with emphasis on formation mechanisms, precursor selection, laser processing strategies, and representative applications. We discuss the key processes governing LIG formation, including sp³-to-sp² carbon rearrangement, gas-release-driven pore formation, and the effects of precursor chemistry and laser parameters on structural quality. We further compare representative substrate classes and highlight process strategies such as defocus control, ion-gel-assisted irradiation, double-sided patterning, and repeated irradiation for tuning morphology and device performance. Recent applications in biosensors, physical and chemical sensors, energy storage, and hybrid multifunctional systems are also reviewed. Finally, current challenges in reproducibility, interfacial robustness, standardization, and scale-up are discussed together with future opportunities for defect engineering, multimaterial integration, and AI-assisted process optimization.