Continuous flow synthesis and applications of carbon dots: a mini-review

Carbon dots (CDs) are gaining growing interest within the scientific community thanks to their unique properties in high value applications. Currently, major issues are their scale-up synthesis, and the control of the reaction conditions both for their production and their application. Continuous flow (CF) chemistry and technologies can be valuable solutions to overcome these problems allowing precise control over critical synthetic parameters in a reproducible and more productive way. CF synthesis can lead to nanoparticles with more easily tunable and controllable properties (i.e. narrower size distribution and higher quantum yield) compared to common batch methodologies. In addition, the small environmental impact and high efficiency of CF can pave the way to large scale production and application of the carbon nanomaterials. For instance, supercritical water is a promising reaction medium to carry out the CF synthesis of CDs in very short time. This review showcases CF procedures for the preparation of CDs, their applications in CF photocatalysis and other niche uses, and gives some ideas on future perspectives in the field.