R. Buiculescu, M. Fouskaki, N.A. Chaniotakis
University of Crete, Greece
pp. 129 - 132
Keywords: carbon dots, nanodots, selective recognition, pH, cation, fluorescence
In the present work, custom designed and synthesized carbon nanodots (C-dots) with cation selective functional organic ligands (carboxyl or amino) are used for the optical detection of cations. The ligands on the surface are able to provide the capping for the C-dots, while at the same time interact selectively with positively charged ions. Controlled experiments with carboxylated and aminated C-dots suggest that their fluorescence is highly dependent on the electrical field generated on their surface from the selective interaction of the charge ions with the functional sites of the C-dots. This charge can be developed selectively using different functionalities with different binding constants to monovalent and divalent metal ions. This allows for the selective optical detection using functionalized C-dots. While the fluorescence of the aminated C-dots is dependent on the pH of the solution, they do not respond to monovalent cations and have different response to divalent cations. On the other hand, the fluorescence of the carboxylated C-dots is influenced by certain divalent oxophilic metal ions. These observations set the grounds for the development of highly selective fluorescent nanoindicators based on C-dots, and their further deployment in the development of novel chemical and bio-sensing biocompatible systems.