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.