A Fluorescence Probe for Metal Ions Based on Black Phosphorus Quantum Dots

Fluorescence method for detecting metal ions has advantages of fast detection speed, simple operation, and low price over the conventional methods. Black phosphorus quantum dots (BP QDs) have high photoluminescence quantum yield and modifiable surface, which have great potential in the field of fluorescent probes. In this study, high quality BP QDs are prepared by pyrolysis method and are first time used as trace metal ion probes in both organic solutions and aqueous solutions. The detection limits of Hg2+ and Cu2+ in the aqueous solution are 5.3 x 10(-9) m and 1.6 x 10(-6) m, respectively. In addition, the detection limits of Cu2+ in the organic solution are 16 x 10(-6) m. The fluorescence quenching mechanism based on the calculation of the electronic structure and adsorption energy of BP QDs after adsorption of metal ions is further explained. The results provide a new promising fluorescence probe for trace metal ions without the help of organic molecules.