writer：Wenyuan Xie, Xing Yu, Weiming Wu, Yushan Liu, Chenguang Jiang, Ming Yin, Tian Tian, Shubin Wang
keywords：Carbon nanodots Nitrogen-doped, Structural composition, Fluorescence properties, Defect state effect.
source：期刊
specific source：ACS Applied Polymer Materials
Issue time：2022年

ACS Applied Polymer Materials, 2022, 4(7), 4784-4795. 

For applications in the fields of biological imaging and chemical sensing, fluorescent carbon nanodots (CNDs) have excellent possibilities because of their unique structure and performance. In this work, we synthesized a series of nitrogen-doped CNDs (N-CNDs) with different fluorescent emission, ranging from blue to yellow, via one-pot solvothermal strategy. Citric acid and urea were employed as the precursors. And formamide, ethanol and N, N-dimethylformamide were used as the solvent respectively. The excitation-dependent emission and the optimal emission were measured with the ultraviolet-visible and photoluminescence spectra. The morphology and chemical structure of the prepared N-CNDs were characterized via high-resolution transmission electron microscope (HRTEM), atomic force microscope (AFM), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, carbon nuclear magnetic resonance (13C NMR) spectroscopy, etc. The influence of reaction time, temperature and type of solvent on the structure of N-CNDs were systematically investigated. The photoluminescence mechanism was discussed based on the chemical structure, the crystallinity and the sp2/sp3 carbon ratio of the prepared N-CNDs. In addition, a biocompatible amphiphilic copolymer mPEG-b-PLLA was synthesized and self-assembled in an aqueous system. The prepared N-CNDs were introduced into the polymer self-assemblies as a fluorescent probe by an in-situ grafting method. The fluorescence imaging performance of N-CNDs in the polymer self-assemblies was investigated by comparing with organic fluorescent dye coumarin-6.

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https://pubs.acs.org/doi/10.1021/acsapm.2c00385