The synthesis of low-cost and high-efficiency multicolour emitting graphene quantum dots (GQDs) is of utmost importance for their prospective applications. Lignin, a renewable biomass, contains aromatic compounds that are well-suited for the preparation of polycyclic aromatic GQDs. In this study, we successfully synthesized red, yellow, green, and blue light-emitting single-layered GQDs with high crystallization using hydrothermal methods, thereby covering the full spectrum of visible light. High-resolution transmission electron microscopy (HRTEM) images revealed the presence of a two-dimensio...
