Title of Paper:Chemically Tailoring Coal to Fluorescent Carbon Dots with Tuned Size and Their Capacity for Cu(II) Detection

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Date of Publication:2014-12-10

Journal:SMALL

Included Journals:SCIE、EI、PubMed、Scopus

Volume:10

Issue:23

Page Number:4926-4933

ISSN No.:1613-6810

Key Words:carbon dots,coal,fluorescence,nanoparticles

Abstract:The desired control of size, structure, and optical properties of fluorescent carbon dots (CDs) is critical for understanding the fluorescence mechanism and exploring their potential application. Herein, a top-down strategy to chemically tailor the inexpensive coal to fluorescent CDs by a combined method of carbonization and acidic oxidation etching is reported. The size and optical properties of the as-made CDs are tuned by controlling the structures of graphitic crystallites in the starting precursor. The coal-derived CDs exhibit two different distinctive emission modes, where the intensity of the short-wavelength emission is significantly enhanced by partial reduction treatment. The evolution of the electronic structure and the surface states analysis show that two different types of fluorescence centers, nano-sized sp(2) carbon domains and surface defects, are responsible for the observed emission characteristics. The reduced CDs are demonstrated as an effective fluorescent sensing material for label-free and selective detection of Cu(II) ions with a detection limit as low as 2.0 nM, showing a great promise for real-world sensor applications.