Large Scale Synthesis of Carbon Dots and Their Applications: A Review

Carbon dots (CDs), a versatile class of fluorescent carbon-based nanomaterials, have attracted widespread attention due to their exceptional optical properties, biocompatibility, and cost-effectiveness. Their applications span biomedicine, optoelectronics, and smart food packaging, yet large-scale synthesis remains a significant challenge. This review categorizes large-scale synthesis methods into liquid-phase (hydrothermal/solvothermal, microwave-assisted, magnetic hyperthermia, aldol condensation polymerization), gas-phase (plasma synthesis), solid-phase (pyrolysis, oxidation/carbonization, ball milling), and emerging techniques (microfluidic, ultrasonic, molten-salt). Notably, microwave-assisted and solid-state synthesis methods show promise for industrial production due to their scalability and efficiency. Despite these advances, challenges persist in optimizing synthesis reproducibility, reducing energy consumption, and developing purification methods and quality control strategies. Addressing these issues will be critical for transitioning CDs from laboratory research to real-world applications.