Green Synthesis of Multi-Functional Carbon Dots and their Applications

Abstract: Carbon Quantum Dots (CQDs) are a promising class of nanomaterials with unique optical properties, making them highly suitable for applications in bioimaging, drug delivery, and sensors. However, traditional synthesis methods often rely on toxic precursors and harsh conditions, raising concerns about environmental sustainability and safety. To address these issues, green synthesis methods have garnered attention as eco-friendly alternatives, utilizing renewable resources such as plant extracts, biomass, and waste materials. These sustainable approaches not only minimize environmental impact but also enhance the functional properties of CQDs, making them more suitable for biomedical and technological applications. The green synthesis of CQDs typically involves hydrothermal or solvothermal processes, where renewable precursors are converted into CQDs under mild conditions. This results in CQDs with excellent photoluminescence, stability, and biocompatibility, which are essential for their integration into practical applications. Moreover, the use of natural compounds during synthesis can impart bioactive properties to CQDs, expanding their potential for cancer therapy, environmental monitoring, and photocatalysis. Despite the progress in green synthesis, challenges remain in optimizing the synthesis parameters and scaling up production for industrial use. Future research should focus on refining these methods to improve yield, enhance the functional properties of CQDs, and reduce the environmental impact associated with their production. This review underscores the significance of green synthesis approaches in the development of CQDs, highlighting key techniques such as hydrothermal and solvothermal methods and exploring their potential applications in various fields. The promising advances in green synthesis position CQDs as a sustainable solution for numerous technological and biomedical applications.