Journal of Fluorescence

, Volume 26, Issue 1, pp 283–295 | Cite as

Interaction of Graphene Quantum Dots with 4-Acetamido-2,2,6,6-Tetramethylpiperidine-Oxyl Free Radicals: A Spectroscopic and Fluorimetric Study

  • Ojodomo J. Achadu
  • Tebello Nyokong


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.


Graphene quantum dots Free radicals Fluorescence quenching Stern-volmer quenching constant 



This work was supported by the Department of Science and Technology (DST) and National Research Foundation (NRF), South Africa, through DST/NRF South African Research Chairs Initiative for Professor of Medicinal Chemistry and Nanotechnology (UID 62620) as well as Rhodes University/DST Centre for Nanotechnology Innovation, Rhodes University, South Africa.

Compliance with Ethical Standards

Conflicts of Interest

There are no potential conflicts of interest with regard to this manuscript.


The funders have agreed to publication.

Human and Animal Studies

The research does not involve human participants and/or Animals.

Supplementary material

10895_2015_1712_MOESM1_ESM.docx (83 kb)
Fig. S1 (DOCX 82 kb)


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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  1. 1.Department of ChemistryRhodes UniversityGrahamstownSouth Africa

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