title: Interaction of Graphene Quantum Dots with 4-Acetamido-2,2,6,6-Tetramethylpiperidine-Oxyl Free Radicals: A Spectroscopic and Fluorimetric Study.
abstract: We report on the interaction of graphene quantum dots (GQDs) with 4-acetamido-2,2,6,6-tetramethylpiperidine-oxyl (4-acetamido-TEMPO) free radicals. The GQDs were N and S, N doped. The fluorescence quantum yields were higher for the doped GQDs compared to the undoped. The interaction is assessed by spectrofluorimetric, steady state/time resolved fluorescence and electron paramagnetic resonance (EPR) techniques. Fluorescence quenching was observed upon the addition of 4-acetamido-TEMPO to the GQDs. Photo-induced electron transfer (PET) mechanism was suggested as the plausible mechanism involved in the fluorescence quenching in which 4-acetamido-TEMPO acted as the electron acceptor.
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown, 6140, South Africa.
authors.forename: Ojodomo J
authors.initials: OJ
authors.lastname: Achadu
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown, 6140, South Africa. t.nyokong@ru.ac.za.
authors.forename: Tebello
authors.initials: T
authors.lastname: Nyokong
keywords: Fluorescence quenching; Free radicals; Graphene quantum dots; Stern-volmer quenching constant