Role of functionalization in the fluorescence quantum yield of graphene quantum dots

As graphene is sculptured into quantum dots, confinement and edge effects induce a finite energy gap trigger exotic photoluminescent behavior. However, synthesis of dots (GQDs) with high fluorescence yield designated emission color remains challenging, due to lack knowledge in the exact influences various structural chemical factors. Herein, we explore optical absorption GQDs surface functionalization, heteroatom doping, or modification. Their spectra are systematically compared by time-dependent density functional theory calculations. It shows that sp 3 -type functionalization O, OH, F groups can effectively increase intensity five orders magnitude regard pristine GQDs, ascribed localization excited carriers enlarges transition dipole moment for radiative decay. The also play key role fluorescent sensing toxic metal species selectivity sensitivity.