CDs microcapsules polyurethane film with improved light environment, self-healing and high strength for plant greenhouses to promote plant growth

Carbon dots (CDs) have photoconversion performance and have a wide range of applications in agriculture. However, the solution of CDs is susceptible to quench under evaporation of sunlight and is easy to run-off when influenced by the external environment. Here, PVA-coated CDs were used to overcome the solid-state quenching and to prepare CDs microcapsules-polyurethane Film for plant cultivation. In this work, CDs microcapsules which can convert ultraviolet light into blue light for plant growth, were prepared by the "water/oil/water" method, and light-converting CDs microcapsules polyurethane film (CMPF) was prepared by doping CDs microcapsules with polyurethane. The study showed that polyurethane film has good mechanical properties and self-healing ability, the CMPF was able to effectively promote the growth of lettuce, and the effect was most significant at the CDs microcapsules concentration of 4000 mg/L. Compared with the blank group, the fresh and dry weights were increased by 177% and 143.5%, respectively, and the content of chlorophyll a, chlorophyll b, carotenoids, and soluble protein were increased by 14.5%, 188.5%, 43.3%, and 17.9%, respectively. Application of CDs to modulate plant lighting growth regulators for efficient use of ultraviolet (UV) light.