Carbon dots (CDs) are a novel class of 0-dimensional nanoparticles that belongs to the carbon-based family materials, characterized by a graphene-like core surrounded by amorphous-functionalized carbon, with dimensions under 20 nm, that have been reported for the first time in 2004 ^[1].

In recent years they have gained considerable attention due to their advantageous features, including easy bottom-up synthesis from a wide variety and low-cost starting materials, biocompatibility, low cytotoxicity, tunable photoluminescence, and photo-induced electron transfer capabilities. These properties make them highly versatile in fields such as sensing, bio-imaging, catalysis, photodynamic therapy and opto-electronic devices ^[2]. Their useful properties and applications arouse interest in the comprehension of these new materials that are eligible as the new organic counterpart of the metal-based quantum dots. However, understanding the correlation between their optical properties and nanoparticle structure remains challenging for most carbon dots.

In this contribute the photophysical properties of CDs obtained as described in literature from Citric Acid, Formic Acid and Urea were studied in two different solvents, water and DMSO and under nitrogen and oxygen atmosphere. The results indicate a possible doping effect of Oxygen which significantly impacts the optical proprieties.

[1] Xu X. et al., Journal of the American Chemical Society, (2004), 12736-12737, 126(40).

[2] Cui L. et al., Nanomaterials, (2021), 3419, 11(12).