Citrus aurantium as an economical and massive source of carbon in CQDs synthesis for bandgap tunning in optoelectronic applications

Abstract

Abstract As a promising quantum material, carbon quantum dots (CQDs) have been widely applied in almost every optoelectronics device and application but the conventional synthesis methods were not eco-friendly due to the use of toxic and heavy metals. We explored an entirely novel approach, utilizing citrus aurantium (bitter orange) as the carbon source and produced CQDs with 4–6 nanometers in diameter and blue, green, and orange emissions. For the purpose of bandgap tuning, we were able to increase the bandgap energy of CQDs by adding a certain amount of urea and polyethylene glycol to the precursor solution in the synthesis procedure. The bandgap energy of CQDs increased from 2.5 to roughly 3.8 eV. Our approach is thoroughly new which brings about a facile, eco-friendly, and low-cost synthesis method.