Lasing of carbon dots: Chemical design, mechanisms, and bright future

Carbon dots (CDs) are a new solution-processable laser material. They offer advantages of non-toxicity, low cost, and high stability, making them attractive for the sustainable development of miniaturized lasers. Research into CD lasing is currently flourishing. However, the mechanisms of CD lasing have been poorly studied. Consequently, there are no strategies for guiding the design and synthesis of CD laser material with a low threshold. This review summarizes the methods of preparing high-gain and high-stability CDs and the reported laser devices. It explores the laser mechanisms and proposes approaches to decrease the factors influencing lasing. Then, it prospects the potential applications of CD lasers. Finally, the challenges of developing CD-based continuous-wave lasers and electrically pumped lasers are discussed, along with strategies for optimizing the materials and devices. Overall, this work is expected to provide systematic research ideas for the development of CD gain materials and laser devices and their wide applications.