title: Synthesis of highly fluorescent nitrogen-doped graphene quantum dots for sensitive, label-free detection of Fe (III) in aqueous media.
abstract: Heteroatom doping can drastically alter the electronic characteristics of graphene quantum dots (GQDs), thus resulting in unusual properties and related applications. Herein, we develop a simple and low-cost synthetic strategy to prepare nitrogen-doped GQDs (N-GQDs) through hydrothermal treatment of GQDs with hydrazine. The obtained N-GQDs with oxygen-rich functional groups exhibit a strong blue emission with 23.3% quantum yield (QY). Compared to GQDs, the N-GQDs exhibit enhanced fluorescence with blue-shifted energy. Due to the selective coordination to Fe(3+), the N-GQDs can be used as a green and facile sensing platform for label-free sensitive and selective detection of Fe (III) ions in aqueous solution and real water samples. The N-GQDs fluorescence probe shows a sensitive response to Fe(3+) in a wide concentration range of 1-1945μM with a detection limit of 90nM (s/N=3). Interestingly, it is also found that both dynamic and static quenching processes occur for the detection of Fe(3+) by N-GQDs, while the quenching effect of Fe(3+) on the fluorescence of GQDs is achieved by affecting the surface states of GQDs.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Ju
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China. Electronic address: weichen@ciac.ac.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D007501:Iron / Q000032:analysis*; D008832:Microchemistry / Q000295:instrumentation; D009584:Nitrogen / Q000737:chemistry*; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D006108:Graphite; D007501:Iron; D009584:Nitrogen
keywords: Chemical sensor; Fluorescence; Graphene; Iron ions; Quantum dots