Title : Study of Highly Fluorescent Carbon Quantum Dots derived from Swertia chirata
Abstract:
Nanotechnology have reached to every dimension of science and Quantum Dots. Green synthesis of carbon quantum dots (CQDs) help in attaining quantum mechanical properties in an affordable and optimizable way among synthetic routes of CQDs through chemical/biological carbon precursors. The CQDs have been applied to photo-sensing of organic molecules, metal ions, and biological materials like hemoglobin, RNA, cancerous cells etc, photo catalysis, photo degradation and Photodynamic studies. We have planned synthesis of CQDs through pyrolysis of pharmaceutically relevant Swertia chirata plant powder. The quantum confinement effect, 2.46 eV photo excitable band gap, and 27.8% fluorescence quantum yield of aqueous 6.25 mg L-1 CQDs were confirmed using absorption-emission spectroscopy. X-ray diffraction and FTIR studies reveal the multiphasic nature of pyrolytic products confirming the presence of nano graphite, graphene oxide, carbon nanotube and fullerene-like systems. Porous non-crystalline, fullerene-like CQDs were extracted from these pyrolytic products and its particle size was found to be 8.63 nm. Tauc and Williamson-Hall plots were stimulated using FORTRAN programming. Quantum mechanical Brus-Kayanuma equation confirms 34% of quantum confinement with effective e/h mass of 0.053m’e and correlates the synthesized CQDs with N, S-doped lower fullerenes. Semi qualitative sunlight-induced photo degradation studies were performed using CQDs against methylene blue dye revealing complete photo degradation within 1 hour at room temperature after 30 min dark phase of adsorption. Studies confirmed high application of CQDs exhibiting its wider scope in future.
