White-emissive boron and nitrogen co-doped carbon dots for detection of water in organic solvents and Fe3+ ions

In this paper, boron and nitrogen co-doped carbon dots (BN-CDs) were prepared by a simple one-step solvothermal method. The synthesis involved citric acid as the carbon source, boric acid as the boron source, urea, and ammonia as the nitrogen sources, with N, N-Dimethylformamide (DMF) serving as the solvent. The BN-CDs exhibited dual emission peaks at 440   nm and 570   nm under 310   nm excitation wavelength, and white-light emission with chromatographic coordinates of (0.31, 0.33) was achieved. In addition, fluorescence probes based on BN-CDs were carried out in sensing water content in solvent and metal ion. Notably, BN-CDs exhibited a special solvation effect, with the limit of detection (LOD) of 0.075-1.5% as fluorescence probes on water content in dimethyl sulfoxide (DMSO), ethyl alcohol (EtOH), isopropanol (IPA), N-methyl pyrrolidone (NMP) and DMF. Furthermore, both emissions quenched linearly by Fe 3+ ions, proposing a sensitive method for selective ion detection with promising detection limits of 4.5 uM. These findings underscore the multifunctional potential of BN-CDs as versatile fluorescent probes for various sensing applications.