Carbon dots from fuel-rich combustion: analysis of absorption and emission spectra of size-segregated components of blue-fluorescing species

Carbon dots (CDs) are a new class of luminescent carbon-based nanoparticles presenting significant advantages in terms of toxicity, biocompatibility and chemical stability in comparison to semiconductor quantum dots and organic dyes. Flame synthesis in fuel-rich conditions has shown to be a promising controllable method for the simultaneous production of blue- and green-fluorescent CDs. In this work the analytical high performance of size exclusion-chromatography equipped with absorbance and fluorescence detections was used to trace the optical properties of blue CDs produced in a fuel-rich laminar premixed flame as a function of the molecular weight (MW). UV-Visible and fluorescence spectra were analysed on line for each size/MW segregated fraction allowing the determination of its optical band gap and quantum yield important for evaluating CD performance.