Chiral Graphene Quantum Dots and Carbon Dots: From Chirality Induction to Spin-Selective Effects and Advanced Applications

Chiral graphene quantum dots (GQDs) and carbon dots (CDs) represent a groundbreaking fusion of carbon nanotechnology and chirality science. These nanomaterials transcend their achiral counterparts by integrating exceptional biocompatibility and tunable photoluminescence with sophisticated chiroptical properties and the chirality-induced spin selectivity (CISS) effect. This review provides a comprehensive and critical analysis of the rapid evolution of this dynamic field. We first elucidate the fundamental origins of chirality—from chiral surface functionalization and intrinsic lattice distortion to supramolecular assembly—and detail the advanced spectroscopic techniques for its quantification. A systematic evaluation of synthetic methodologies, spanning one-step, two-step, and chiral composite strategies, is presented, highlighting the critical trade-offs between structural control and chiroptical strength. The discussion of core properties delves beyond conventional photoluminescence to explore the mechanisms and tunability of circularly polarized luminescence, room-temperature phosphorescence, and the transformative CISS effect. We subsequently explore how these properties enable state-of-the-art applications in enantioselective biosensing, targeted bioimaging and drug delivery, asymmetric catalysis, and next-generation spin-optoelectronics. The review concludes with a forward-looking perspective, outlining the key scientific challenges in synthesis, stability, and fundamental understanding that must be overcome to transition these promising materials from laboratory demonstrations to practical technologies.