Carbon quantum dots (CDs) are a class of carbon nanomaterials discovered in the beginning of the 21st century. They have been widely studied due to their excellent photoluminescence properties, ease of surface modification, and low toxicity. Because of CDs’ favorable properties they have been applied in fields such as bioimaging, drug delivery, photocatalysis, and 3D-printing. Despite the large interest in CDs’ biomedical applications, they remain limited due to commonly possessing short wavelength emission of blue and green light which can be reabsorbed by biological tissue or concealed by autofluorescence. CDs’ photoluminescence wavelengths have been increased in recent years, but there are few reports containing CDs with emission of red light and there appears to be none which have the desired emission in aqueous solutions. In this talk the preparation of CDs utilizing a solvent of different acids will be presented. The products were characterized by their optical, morphological, and surface properties. Fractions of the crude mixture of CDs possess emission across the visible spectrum of light, culminating with emission approximately at 700 nm. Important factors in the preparation appears to be the acidic and oxidative properties of the solvent used. The red emission of these CDs occurs mainly in alcohol-based solutions; therefore, strategies must be sought after which can transfer this long wavelength photoluminescence from organic solvents to water. This will be a necessity in order to utilize these CDs in biomedical applications.

Additional author(s): Roger M. Leblanc