Luminescent monodispersed carbon quantum dots by a microwave solvothermal method toward bioimaging applications

We report the synthesis of yellow luminescent carbon quantum dots (CDQs; size: 2-9 nm) whose surface was functionalized with polyethylene glycol (PEG-6000) using a novel low-pressure microwave solvothermal method (MWS) that yielded highly emitting CQDs with quantum yields up to 61.1 % at lambda em =580 nm. The resulting quantum dots were characterized by 500-MHz 1H- and 13C-NMR, by FT-IR, UV-vis and photoluminescence spectroscopies, by XRD and XPS, by TEM microscopy, and by dynamic light scattering (DLS) techniques. A comparison between the MWS method and the conventional autoclave solvothermal (CAS) method demonstrated significant advantages of the novel MWS methodology, which can find further applications in studies of state-ofthe-art syntheses of CQDs, in particular, and potentially other quantum dots, in general.

Automated summary

A novel low-pressure microwave solvothermal method was reported for the synthesis of yellow luminescent carbon quantum dots, showing significant advantages compared to the conventional autoclave solvothermal method. The highly emitting CQDs synthesized using this method can find further applications in state-of-the-art studies of CQDs and potentially other quantum dots.