Smart Incorporation of Fluorescent Carbon Dots With Photosynthesis‐Inhibiting Herbicide for Promotion of Sustainable Weed Management

The practical efficacy of herbicides in inhibiting the photosynthetic pathway of weeds is often compromised by the limited utilization of solar energy, making their performance highly susceptible to fluctuating light conditions in diverse agricultural environments. Here, by heating a mixture of citric acid (CA), urea (UA), and acifluorfen (ACI, a representative photosynthesis-inhibiting herbicide) under solvent-free conditions at atmospheric pressure, carbon dots-based fluorescent nano-assembly (ACI@CU CDs) was constructed through non-covalent interactions. The CU CDs in the nano-assembly functioned as a supplementary light source, in situ converting the ultraviolet portion of sunlight into visible wavelengths to provide protoporphyrin IX (PpIX) with additional excitation light. Under different light intensities, the results from both greenhouse and field experiments showed that the herbicidal activities of ACI@CU CDs against various weeds were significantly higher than those of ACI. The safety evaluation of ACI@CU CDs, conducted on soybean and Vicia faba, indicated negligible risk to non-target plants. In addition, the fluorescent nano-assembly could reduce the leaching potential of ACI in soils and exert minimal influence on soil enzyme activity as well as microbial diversity. Overall, these findings demonstrate a feasible and promising strategy for enhancing the weed control efficiency and mitigating the environmental impact of photosynthesis-inhibiting herbicides.