Influence of Inert and Oxidizing Atmospheres on the Physical and Optical Properties of Luminescent Carbon Dots Prepared through Pyrolysis of a Model Molecule

• Published in: Chemistry : a European journal 2016-03, Vol.22 (13), p.4556-4563
• Main Authors: Machado, Cláudia Emanuele, Tartuci, Letícia Gazola, de Fátima Gorgulho, Honória, de Oliveira, Luiz Fernando Cappa, Bettini, Jefferson, Pereira dos Santos, Daniela, Ferrari, Jefferson Luis, Schiavon, Marco Antônio
• Format: Article
• Language: English
• Subjects: Atmosphere; Atmospheres; Atomic beam spectroscopy; Carbon; Carbon dots; Chemistry; Inert; luminescence; Nanoparticles; Optical properties; Organic solvents; Oxidation; Oxidizing atmospheres; Physical properties; Potentiometric titration; Pyrolysis; Raman spectroscopy; Solvents; Spectroscopy; Tartaric acid; Titration; X-ray diffraction
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201504234

This work used l‐tartaric acid as a model molecule to evaluate how the use of inert and oxidizing atmospheres during pyrolysis affected the physical and optical properties of the resulting carbon dots (CDs). Pyrolysis revealed to be a simple procedure that afforded CDs in a single step, dismissed the addition of organic solvents, and involved only one extraction stage that employed water. By X‐ray diffraction a dependency between the structure of the CDs and the atmosphere (oxidizing or inert) used during the pyrolysis was found. Potentiometric titration demonstrated that the CDs were largely soluble in water; it also aided characterization of the various groups that contained sp3‐hybridized carbon atoms on the surface of the dots. Raman spectroscopy suggested that different amounts of sp2‐ and sp3‐hybridized carbon atoms emerged on the CDs depending on the pyrolysis atmosphere. In conclusion, the pyrolysis atmosphere influenced the physical properties, such as the composition and the final structure. Properties of C‐dots: The physical and optical properties of carbon dots are closely related to the synthesis conditions and the employed precursor. The choice of the pyrolysis atmosphere for the carbonization of l‐tartaric acid influences the final properties. The adjustments of their properties provide new nanomaterials suitable for future applications (see figure).