title: Synthesis and formation mechanistic investigation of nitrogen-doped carbon dots with high quantum yields and yellowish-green fluorescence.
abstract: Heteroatom doped carbon dots (CDs) have received increasing attention due to their unique properties and related applications. However, previously reported CDs generally show strong emission only in the blue-light region, thus restricting their further applications. And the fundamental investigation on the preparation process is always neglected. Herein, we have developed a simple and solvent-free synthetic strategy to fabricate nitrogen-doped CDs (N-CDs) from citric acid and dicyandiamide. The as-prepared N-CDs exhibited a uniform size distribution, strong yellowish-green fluorescence emission and a high quantum yield of 73.2%. The products obtained at different formation stages were detailedly characterized by transmission electron microscopy, X-ray diffraction spectrometer, X-ray photoelectron spectroscopy and UV absorbance spectroscopy. A possible formation mechanism has thus been proposed including dehydration, polymerization and carbonization. Furthermore, the N-CDs could serve as a facile and label-free probe for the detection of iron and fluorine ions with detection limits of 50 nmol L(-1) and 75 nmol L(-1), respectively.
authors.affiliation: College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, PR China. dinglan@ jlu.edu.cn.
authors.forename: Juan
authors.initials: J
authors.lastname: Hou
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Tianyu
authors.initials: T
authors.lastname: Zhou
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.forename: Huiyu
authors.initials: H
authors.lastname: Li
authors.forename: Lan
authors.initials: L
authors.lastname: Ding