Mechanisms of photoluminescence in the molecular state of carbon dots prepared from o-phenylenediamine

Sun's group from Beijing University of Technology, China, prepared red-emission CDs in high yield by a solvent-free method based on o-phenylenediamine and analyzed the origin of the red emission and the formation of CDs. 5,14-Dihydroquinoxalino[2,3- b ]phenazine (DHQP) was successfully isolated from the system and identified as the fluorophore of the CDs. These findings provide insight into the PL mechanism of this type of CDs and may guide the further development of CDs that can be tuned to obtain tailored properties.