Hydrophobic carbon dots with blue dispersed emission and red aggregation-induced emission

By Haiyao Yang, Yingliang Liu, Zhouyi Guo, B. Lei, J. Zhuang, Xuejie Zhang, Zhiming Liu, Chaofan Hu. Nature Communications, 2019

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Carbon dots (CDs) have been studied for years as one of the most promising fluorescent nanomaterials. However, CDs with red or solid-state fluorescence are rarely reported. Herein, through a one-pot solvothermal treatment, hydrophobic CDs (H-CDs) with blue dispersed emission and red aggregation-induced emission are obtained. When water is introduced, the hydrophobic interaction leads to aggregation of the H-CDs. The formation of H-CD clusters induces the turning off of the blue emission, as the carbonized cores suffer from π-π stacking interactions, and the turning on of the red fluorescence, due to restriction of the surfaces’ intramolecular rotation around disulfide bonds, which conforms to the aggregation-induced-emission phenomenon. This on-off fluorescence of the H-CDs is reversible when the H-CD powder is completely dissolved. Moreover, the H-CD solution dispersed in filter paper is nearly colorless. Finally, we develop a reversible two switch-mode luminescence ink for advanced anti-counterfeiting and dual-encryption. Carbon dots that display long-wavelength and multicolor emission are desirable for biological and anti-counterfeiting applications. Here, the authors design hydrophobic carbon dots with reversible two-mode fluorescence, which exhibit blue emission when dissolved in solution, and red solid-state fluorescence when aggregated.

Subfields: Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/163c06fe14ebdc26640bd909c58a3b03343c25c1