Efficient water‐soluble blue/red‐emissive carbon dots matching plant absorption spectra: Synthesis, tunable control, and their applications in promoting plant growth

Abstract Amid growing food demand and the need for resilient agroecosystems, improving crop photosynthetic efficiency is crucial for sustainable agriculture. Carbon dots (CDs), an emerging class of carbon‐based nanomaterials, show strong potential for enhancing plant light‐use efficiency owing to their tunable photoluminescence, high water solubility, adjustable quasi‐core‐shell structure, and excellent biocompatibility. Focusing on the selective spectral response of plant photosynthetic systems, this review systematically summarizes the design principles and recent advances of water‐soluble, high‐efficiency blue‐emissive CDs (400–480 nm, photoluminescence quantum yield (PLQY) ≥ 60%) and red‐emissive CDs (600–700 nm, PLQY ≥ 15%; water solubility ≥10 mg mL −1 ) for spectral matching. First, from the perspective of synthetic modulation, we outline key strategies—including the selection of high‐quantum‐yield precursors, optimization of reaction conditions, and heteroatom doping—in constructing emissive centers and tailoring emission wavelengths. Subsequently, we highlight the multifunctional roles of CDs in plant systems. On the one hand, CDs enable spectral conversion by transforming ultraviolet light into photosynthetically active radiation, thereby facilitating efficient light‐energy redistribution. On the other hand, through coupling with the photosynthetic electron transport chain, CDs can modulate electron transfer processes and enhance downstream assimilatory metabolism. Building upon these mechanistic insights, we further evaluate the feasibility of synergistic blue‐red dual‐emission regulation strategies, as well as the scalability of CD synthesis for practical applications. Finally, we identify the key challenges that must be addressed for translating spectrally matched CDs from laboratory research to field deployment, and provide an outlook on their future development in enabling green and high‐efficiency agriculture.