Tailoring color emissions from N-doped graphene quantum dots for bioimaging applications
Unlike inorganic quantum dots, fluorescent graphene quantum dots (GQDs) display excitation-dependent multiple color emission. In this study, we report N-doped GQDs (N-GQDs) with tailored single color emission by tuning π -conjugation degree, which is comparable to the inorganic quantum dot. Starting from citric acid and diethylenetriamine, as prepared N-GQDs display blue, green, and yellow light emission by changing the reaction solvent from water, dimethylformamide (DMF), and solvent free. The X-ray photoelectron spectroscopy, ultraviolet-visible spectra results clearly show the N-GQDs with blue emission (N-GQDs-B) have relatively short effective conjugation length and more carboxyl group because H 2 O is a polar protic solvent, which tends to donate proton to the reagent to depress the H 2 O elimination reaction. On the other hand, the polar aprotic solvent (DMF) cannot donate hydrogen, the elimination of H 2 O is promoted and more nitrogen units enter GQD framework. With the increase of effective π -conjugation length and N content, the emission band of N-GQDS red-shifts to green and yellow. We also demonstrate that N-GQDs could be a potential great biomarker for fluorescent bioimaging.
危险品化学品经营许可证（带存储）