Green fabrication of fluorescent N-doped carbon quantum dots from Aegle marmelos leaves for highly selective detection of Fe³⁺ metal ions

This current study uses a simple, environmentally friendly, and economically advantageous Microwave method to create water-soluble carbon dots from Aegle marmelos leaves. Nitrogen-doped carbon dots (N-CQDs) that have been produced exhibit outstanding benefits such as water solubility, biocompatibility, and high stability. Essential characterization methods are used to examine it, including XRD, FTIR, HR-TEM, XPS, UV–vis, and fluorescence spectroscopy. It exhibits excitation-dependent emission behavior, blue emission under UV lamp illumination (wavelength 365 nm), and pH independence. Synthesized N-CQDs with a quantum yield of 14.21 % responded exceptionally well to Fe³⁺ ions, which causes fluorescence to quench. A single probe fluorescence-based system for detecting Fe³⁺ ions with high selectivity and sensitivity was designed. Under optimized fluorescence experimental conditions, the linear range of Fe³⁺ ions was 0–20 μM with a detection limit of 0.184 µM (R² = 0.99363). The produced N-CQDs respond exceptionally well to Fe³⁺ ions, which causes fluorescence to quench. This study demonstrates a single probe FL-based device for detecting Fe³⁺ ions with high sensitivity and selectivity.