Passivator-Free Microwave–Hydrothermal Synthesis of High Quantum Yield Carbon Dots for All-Carbon Fluorescent Nanocomposite Films

• Published in: Nanomaterials (Basel, Switzerland) Switzerland), 2022-07, Vol.12 (15), p.2624
• Main Authors: Wu, Jiayin, Lu, Qilin, Wang, Hanchen, Huang, Biao
• Format: Article
• Language: English
• Subjects: Aldehydes; Amino groups; Biosensors; Carbon; Carbon dots; Cellulose; Chitosan; fluorescent composite film; Fluorescent indicators; Fourier transforms; Imines; Iron; iron ion detection; Mechanical properties; nanocellulose; Nanocomposites; Nanoparticles; Optical properties; Photocatalysis; Quantum dots; R&D; Research & development; Selectivity; Spectrum analysis; Synthesis
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano12152624

Based on the self-passivation function of chitosan, an efficient, and green synthesis strategy was applied to prepare chitosan carbon dots (CDs). The quantum yield of carbon dots reached 35% under the conditions of hydrothermal temperature of 200 °C, hydrothermal time of 5 h, and chitosan concentration of 2%. Moreover, the obtained carbon dots had high selectivity and sensitivity to Fe3+. Based on the Schiff base reaction between the aldehyde groups of dialdehyde cellulose nanofibrils (DNF) and the amino groups of CDs, a chemically cross-linked, novel, fluorescent composite film, with high transparency and high strength, was created using one-pot processing. Knowing that the fluorescence effect of the composite film on Fe3+ had a linear relationship in the concentration range of 0–100 μM, a fluorescent probe can be developed for quantitative analysis and detection of Fe3+. Owing to their excellent fluorescent and mechanical properties, the fluorescent nanocomposite films have potential applications in the fields of Fe3+ detection, fluorescent labeling, and biosensing.