Preparation and Optical Characterization of Colloidal Carbon Quantum Dots

This paper presents optical properties of colloidal carbon quantum dots C-QDs in distilled water produced by using a method of alkali-assisted surfactant-free oxidation of cellulose acetate. The formation of colloidal carbon nanocrystals with the size range of ~ 4-5 nm was confirmed by using high-resolution transmission electron microscopy. The photoluminescence PL properties of the colloid were investigated at different applied excitation wavelengths and we observed a wide range of tunable visible to near-infrared NIR emissions with good stability from the C-QD colloid. A detailed analysis of the results shows that the visible and NIR luminescent properties of the colloidal C-QDs can be attributed to the mechanisms of quantum confinement and surface effects, respectively.