Lignin-derived High-quality Graphene Quantum Dots: Synthesis, Mechanistic Insights, and Emerging Applications

Lignin-based graphene quantum dots (L-GQDs), serving as a bridge between renewable biomass resources and functional carbon materials. This review begins with the molecular structure of lignin, exploring various synthesis methods for L-GQDs. The precise elucidation of precursor-structure-property relationships could optimize their performance through the quantitative regulation of lignin unit properties and enable controllable synthesis. We elaborate on the photoluminescence mechanisms and fluorescence modulation strategies of L-GQDs, covering aspects such as structural design, synthesis pathways, and photophysical property optimization. Additionally, the review discusses the application prospects of L-GQDs in biology, energy conversion, and optoelectronics, and highlights the importance of synergistically aligning synthesis strategies with practical on-demands application. We also prospected research paradigm should focus on in-situ unveiling of nucleation kinetics during L-GQDs formation, photoluminescence mechanism decoding, toxicity regulation to enable green, sustainable and multidisciplinary cutting-edge applications.