Carbon dots: from fundamentals to frontier applications

Carbon dots (CDs), as emerging zero-dimensional carbon-based nanomaterials, demonstrate immense potential across optical displays, bioimaging, chemical sensing, information anti-counterfeiting, and optoelectronic devices. This promise stems from their exceptional tunable photoluminescence, low toxicity, biocompatibility, and abundant raw material sources. Since their discovery, research has centered on resolving controversies regarding classification, formation mechanism, microstructure, and luminescence principles while achieving controllable optoelectronic properties. Applications have evolved from basic fluorescent labeling to advanced domains including multimodal theranostics, high-sensitivity (bio/chemical) sensing, stable optoelectronic devices, intelligent anti-counterfeiting systems, and environmental/energy catalysis. Future challenges demand breakthroughs in structural homogeneity/scalable eco-fabrication, universal structure-opto/electronic-property models, stability/efficiency in complex environments, and multifunctional synergy (e.g., photo-electro-catalysis). This comprehensive review systematically examines milestone advances in CDs research over the past decade—spanning synthesis methodologies, photo/electronic property modulation mechanisms, and innovative applications—while dissecting key challenges and envisioning future pathways as versatile intelligent nanoplatforms.