Dramatic Fluorescence Enhancement of Bare Carbon Dots through Facile Reduction Chemistry

doi:10.1002/cphc.201200018

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	Dramatic Fluorescence Enhancement of Bare Carbon Dots through Facile Reduction Chemistry
	Shen, Ran 1; Song, Kai 1; Liu, Huarong 1; Li, Yuesheng 2; Liu, Hewen 1
刊名	CHEMPHYSCHEM
	2012-10-22
卷号	13 期号:15 页码:3549-3555
关键词	Carbon Dots Fluorescence Enhancement Reduction Semiconductors Surface Chemistry
ISSN号	1439-4235
DOI	10.1002/cphc.201200018
英文摘要	Reduction of bare carbon dots (CDs) in aqueous NaBH4 solution is a facile and effective approach to enhance their fluorescence without any surface coverage. CDs are treated with dilute aqueous NaBH4 solutions, enhancing their quantum yields (QYs) successfully from 1.6?% to 16?% which is comparable to semiconductive QDs in aqueous environments. If pristine CDs are treated hydrothermally prior to reduction by NaBH4, QYs reach 40.5?%. This value is among the highest QYs reported for bare CDs in the literature. The approach to enhance fluorescence through chemical reduction is generally applicable to other kinds of CDs synthesized by various methods. Alteration of the chemical structure of the CDs by NaBH4-reduction is analyzed by 13C NMR, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, which demonstrate that the carbonyl group content is decreased after NaBH4-reduction, whereas the number of sp3-type carbon defects is increased. The valence-band maxima (VBM) near the surface related to the surface energy bands of the CDs are estimated by XPS. VBM data show a semiconducting layer on the surface of the CDs, and the VBM of the CDs decrease with increasing NaBH4-reduction time. The layered graphite structures in the cores of the CDs are clearly observed by transmission electron microscopy (TEM). CDs could perhaps be regarded as semiconductive surface defect layers formed by chemical erosion over conductive graphite cores. Chemical reduction by NaBH4 changes the surface-energy bands of the CDs, thus, enhances their fluorescence. The fluorescence properties of aqueous NaBH4-reduced CDs are also studied for possible biological applications.
语种	英语
出版者	WILEY-V C H VERLAG GMBH
WOS记录号	WOS:000309887300019
内容类型	期刊论文
源URL	[http://ir.iccas.ac.cn/handle/121111/48667]
专题	中国科学院化学研究所
通讯作者	Liu, Hewen
作者单位	1.Univ Sci & Technol China, Dept Polymer Sci & Engn, CAS Key Lab Soft Matter Chem, Hefei 230026, Anhui, Peoples R China 2.State Key Lab Polymer Phys & Chem, Changchun, Peoples R China
推荐引用方式 GB/T 7714	Shen, Ran,Song, Kai,Liu, Huarong,et al. Dramatic Fluorescence Enhancement of Bare Carbon Dots through Facile Reduction Chemistry[J]. CHEMPHYSCHEM,2012,13(15):3549-3555.
APA	Shen, Ran,Song, Kai,Liu, Huarong,Li, Yuesheng,&Liu, Hewen.(2012).Dramatic Fluorescence Enhancement of Bare Carbon Dots through Facile Reduction Chemistry.CHEMPHYSCHEM,13(15),3549-3555.
MLA	Shen, Ran,et al."Dramatic Fluorescence Enhancement of Bare Carbon Dots through Facile Reduction Chemistry".CHEMPHYSCHEM 13.15(2012):3549-3555.