Optical and structural characterization of carbon nanodots synthesized by direct carbonization of biomass extracts

Abstract

Carbon nanodots (CNDs) are nanoscale structures with optical and electronic properties of interest for their implementation in the development of sustainable technologies. They can be easily obtained with a reduced environmental impact by direct carbonization of biomass in the presence of oxygen. However, due to the few studies on CNDs synthesized by this method, their optical, electronic and structural properties are not yet fully understood. Therefore, in order to contribute to the understanding of these properties of the synthesized CNDs, this work presents the synthesis of CNDs by direct carbonization of different biomass sources such as lemon, orange, melon, turmeric, carrot, potato, tomato, chili and plum extracts. The CND samples were characterized using scanning electron microscopy (SEM), absorbance (Ab) and photoluminescence (PL) spectroscopy techniques. SEM measurements show CNDs sizes around 30 nm to 60 nm in diameter, on the other hand, Ab spectra showed three common bands at 230 nm, 300 nm and 380 nm. These were attributed to π-π* transitions of C=C bonds, n-π* transiti7ons of C=O bonds and N and Si doping, respectively. Intense PL was observed in the range from 425 nm to 750 nm, making them good candidates for white light emisión applications, among others.