Green‐Mediated Synthesis of Facile Nitrogen‐Doped Carbon Quantum Dots from <i>Dioscorea alata</i> as an Effective Metal Sensing Platform

Abstract New nitrogen‐doped carbon quantum dots (NCQDs) made from Dioscorea alata (DA) extract as the carbon and nitrogen source using the hydrothermal method provide a straightforward approach for extremely sensitive and selective quantification of Cu (II) ions. In this method, aqueous extract of DA served as the carbon source and aqueous ammonia was used as the nitrogen dopant. To characterize NCQDs, a variety of analytical approaches have been utilized. The average size of NCQDs was analyzed using Transmission electron microscopy (TEM) and it was found to be 6.54 nm. Using X‐ray diffraction pattern and Raman spectroscopy, the graphitic nature of the green synthesized NCQDs was investigated. Strong green fluorescence was generated under 365 nm excitation of NCQDs, with an emission wavelength of around 460 nm. Fourier transform infrared analysis confirms the presence of various functional groups in the synthesized NCQDs. The NCQDs have the potential to serve as an extremely sensitive and selective fluorescent probe for Cu (II) ion detection, with a correlation coefficient ( R 2 ) of −0.9927 and a limit of detection of 4.2 nm. The NCQDs were then employed as probes to detect Cu (II) ions in river water and tap water.