It is attractive and encouraging to develop new fluorescent carbon dots (CDs) with excellent optical properties and promising applications prospects. Herein, highly-efficient green emissive CDs (m-CDs) with a high quantum yield (QY) of 71.7% in water are prepared through a facile solvothermal method. Interestingly, the m-CDs exhibit excellent fluorescence stability in the pH range of 1-9. However, the fluorescence intensity of the m-CDs is almost completely quenched as the pH is increased from 9 to 10. The mechanism of the unique pH-responsive behavior is discussed in detail and a plausible mechanism is proposed. Owing to the unique pH-responsive behavior, the m-CDs are used as a on-off fluorescent probe for water quality identification. By combining the reversible pH-ultrasensitive optical properties of the m-CDs in the pH range of 9-10 with the glucose oxidase-mimicking (GOx-mimicking) ability of Au nanoparticles (AuNPs), glucose can be quantitatively detected. Finally, two environment-friendly starch-based solid-state fluorescence materials (powder and film) are developed through green preparation routes.
This work was supported by the National Natural Science Foundation of China (Nos. 21375123, 21675151, and 21721003) and the Ministry of Science and Technology of China (No. 2016YFA0203203).
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