Physical Mechanism of Fluorescence and Chirality of Functionalized Graphene Quantum Dots

In this paper, we theoretically investigate fluorescence and chirality of graphene quantum dots (GQDs) and functionalized GQDs (F-GQDs) in one- and two-photon absorption, stimulated by a recent experimental report (Nanoscale2020, 12, 15823). Our results not only reveal physical mechanism of fluorescence of F-GQDs but also interpret the nature of chirality of F-GQDs, due to the twist geometry by the functionalized edge modification. The transition electric/magnetic dipole moment density reflects the generalized chiral response of F-GQDs, and the structure-activity relationship between the F-GQDs and the chiral properties can be deeply explored from the electronic structure level. Our work not only promotes a deeper understanding of the physical mechanism on fluorescence and chirality of F-GQDs but also opens the possibility for potential applications of F-GQDs.