Single Step Green Synthesis of Carbon Dots from Murraya koenigii leaves; A Unique Turn-off Fluorescent contrivance for Selective Sensing of Cd (II) ion

Cadmium ion is the most toxic metal ion among all the hazardous metals; so, its detection is a crucial area for research and diagnosis. In this article, we have synthesized carbon dots (CDs) from natural source [Murraya koenigii (Curry leaves) leaves] by the hydrothermal method for selective and sensitive detection of Cd2+ ions. The fluorescence quenching of CDs was due to ligand-metal charge transfer (LMCT). The synthesized CDs can donate electrons pair to the excited state vacant d-orbitals of the Cd2+ ions and form a chelate and diminishes the fluorescence intensity of the CDs. The synthesized CDs were characterized by Photoluminescence, UV-visible spectra, zeta potential, XRD, FTIR, HR-TEM, XPS, DLS, and life-time decay analysis. The CDs was highly selective towards Cd2+ ions sensing with broad linear range (0.01-8 mu M) and limit of detection 0.29 nM. More importantly, this synthesized CDs successfully detect the Cd2+ ions in real water samples, and also shows high selectivity to Cd2+ ions even in the occurrence of other interfering metal ions.