Carbon dots-based sensing for smart agriculture

High-quality agricultural development is closely related to people's lives. As smart agriculture evolves, advanced sensing technologies have become indispensable for precision monitoring. While traditional nanomaterials—such as metal-based quantum dots—offer excellent optical properties, their application is often hindered by poor water solubility, high cytotoxicity, and limited biocompatibility. Carbon dots (CDs) have emerged as a superior alternative, offering exceptional fluorescence, low toxicity, and ease of surface functionalization. This review develops a mechanism–application–translation framework for CD-based sensing in smart agriculture. It first connects synthesis, surface chemistry, and photophysical processes with target recognition and optical signal output. Representative applications are then organized into five agricultural domains: environmental monitoring, plant physiological sensing, pathogen detection, agricultural-product quality monitoring, and aquaculture sensing. Cross-cutting barriers, including matrix interference, signal instability, biosafety, synthesis reproducibility, device integration, and field validation, are critically evaluated to identify priorities for translating laboratory probes into deployable agricultural sensors.