Fluorescent graphene quantum dots: Properties regulation, sensing applications, and future prospects

Graphene quantum dots (GQDs), as an emerging class of nascent carbon-based materials, demonstrate remarkable promise in fluorescence sensing applications. Those potentials stem from several factors, including their favorable photoluminescence (PL) characteristics, feasibility of surface functionalization, excellent biocompatibility, and low cytotoxicity. This review concentrates on the fundamental optical properties of GQDs, with specific reference to the manipulation of intrinsic characteristics both by heteroatom doping and surface/edge functionalization. These modifications permit the alteration of optical properties, thereby rendering GQDs more versatile for an array of applications. Subsequently, we then delve into the recent applications of GQDs in fluorescence sensing, encompassing both turn-off and turn-on mechanisms. Finally, it presents a systematic assessment of the current state of research on GQDs, along with discussions on challenges and prospects for expanding and improving their applications. • This review focuses on the fundamental optical properties of GQDs, with particular emphasis on the manipulation of intrinsic characteristics through heteroatom doping and surface/edge functionalization. • Heteroatom doping introduces new energy levels that perturb the local electronic environment and change the bandgap of GQDs, while surface/edge functionalization attaches other polymeric substances to GQDs to alter their optical behavior. • This review evaluates recent research on GQDs in fluorescence sensing, examining various detection mechanisms and discussing the challenges and prospects for expanding and enhancing the application of GQDs in this field.