▎ 摘　　要

Herein, a facile bottom-up approach for producing nitrogen doped graphene quantum dots (N-GQDs) was carried out by the carbonization of citric acid through hydrothermal treatment in the presence of ammonia and a fluorescent sensor for determination of Fe3+ ions has been demonstrated. These synthesized N-GQDs consist mostly of 1-3 layers having a uniform size of about 3.5 nm, and the nitrogen atoms were successfully introduced into the lattice of graphene quantum dots (GQDs). Due to the introduction of nitrogen atoms, N-GQDs exhibit a bright green luminescence with a higher quantum yield of 30.7%, whereas GQDs show a blue luminescence with a quantum yield of 4.5%. Furthermore, a novel sensor application of N-GQDs was performed for a fluorescent sensing platform for the detection of Fe3+ ions with high sensitivity and selectivity. These N-GQDs are promising for applications for biosensors, biological imaging and optoelectronic devices. (C) 2014 Elsevier B.V. All rights reserved.