Near‐Infrared Nano‐Photofertilizer with Red Emission and Micronutrient Release Co‐Enhanced Crop Growth

Conventional fertilizers often exhibit low nutrient‐use efficiency and cause significant environmental issues owing to leaching and volatilization. To address these challenges, a multifunctional nanophotonic fertilizer (L@MgMn) is developed that integrates light conversion, nutrient delivery, and plant monitoring. The system is based on sulfur‐sensitized, lanthanide‐doped nanoparticles (NaGdF 4 :Yb, Er, S@NaGdF 4 :Yb) that emit ultrabright Er 3+ red upconversion (UC) light under near‐infrared (NIR, 980 nm) laser excitation, while suppressing green emission that is not efficiently absorbed by plants. Additionally, the secondary near‐infrared (NIR‐II) fluorescence of the nanoparticles makes it possible to track their movement inside plant tissues. The Mg 2+ /Mn 2+ co‐doped silica shell not only narrows the bandgap, thereby improving the generation of photoinduced electron‐hole pairs, but also facilitates the pH‐responsive release of metal ions in plant cells. Application of L@MgMn at 100 µg mL −1 significantly improves photosynthetic performance in Nicotiana benthamiana , increasing chlorophyll a and b levels by 24.4% and 31.7%, and enhancing biomass by up to 79.6%. The material also demonstrates good antioxidant activity and leaf adherence, thereby improving nutrient uptake efficiency. This study introduces a nanoplatform that simultaneously enhances light utilization, nutrient availability, and plant stress tolerance, thereby offering a new strategy for sustainable and precise agriculture.