Hydrothermal synthesis of ionic liquid-capped carbon quantum dots with high thermal stability and anion responsiveness
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Ionic liquid (1-aminopropyl-3-methyl-imidazolium bromide, [APMIm][Br])-capped carbon quantum dots (CQDs) were obtained by a hydrothermal method. Characterization results demonstrated that the CQDs possessed an average particle size of 2.9 nm, poor crystallinity, and [APMIm][Br] shell linked by amide bond. In addition, the CQD surfaces were also decorated by some oxygen-containing groups. These surface groups made CQDs have an excellent dispersibility in water. The optical property measurements indicated that CQDs aqueous suspension emitted strongest blue fluorescence at 443 nm under 375 nm excitation with a fluorescence quantum yield of 20.3 %. The luminescence property of CQDs in water exhibited excitation wavelength-, concentration-, and pH-dependences, high photostability, and outstanding salt resistance. More importantly, the [APMIm][Br] shell endowed CQDs with a high thermal stability (>300 °C) and an interesting anion responsiveness, i.e., CQDs spontaneously transferred from aqueous phase to ethyl acetate phase once the anion of N(CF3SO2) 2 − was introduced. These particular properties should provide more possibilities for the utility of CQDs in various fields.
KeywordsIonic Liquid High Thermal Stability Fluorescence Quantum Yield Quinine Sulfate Citric Acid Monohydrate
This work was financially supported by the Young Scholars Development Fund of Southwest Petroleum University (No. 201499010109) and National Natural Science Foundation of China (No. 51302273, No. 21403173).
- 28.Li XM, Zhang SL, Kulinich SA, Liu YL, Zeng HB (2014) Engineering surface states of carbon dots to achieve controllable luminescence for solid-luminescent composites and sensitive Be2+ detection. Sci Rep 4:4976Google Scholar
- 36.Liu S, Tian J, Wang L, Zhang Y, Qin X, Luo Y, Asiri AM, Al-Youbi AO, Sun XP (2012) Hydrothermal treatment of grass: a low-cost, green route to nitrogen-doped, carbon-rich, photoluminescent polymer nanodots as an effective fluorescent sensing platform for label-free detection of Cu(II) ions. Adv Mater 24:2037–2041CrossRefGoogle Scholar