Liquid-liquid extraction and visual detection of Hg2+ in aqueous solution by luminescent CsPbBr3 perovskite nanocrystals

All-inorganic cesium lead halide perovskite nanocrystals (PNCs) have not widely been applied for analytical detection due to their insufficient stability in moisture or polar solvents. Herein, we report the first application of luminescent CsPbBr3 PNCs for detecting Hg2+ in water based on liquid/liquid (CCl4/H2O) extraction. In this strategy, the CsPbBr3 PNCs are dissolved in the CCl4 phase and the target Hg2+ are dissolved in the water phase. After the liquid/liquid extraction of Hg2+ from H2O to CCl4, the luminescence of CsPbBr3 PNCs in CCl4 could be quenched by the Hg2+ ions. The CsPbBr3 PNCs can be used as a luminescence probe to realize a rapid, simple, and visual analysis of Hg2+. The Hg2+ concentration in the range from 50.0 nM to 10.0 mu M can be linearly measured with a limit of detection (LOD) of 35.65 nM. The method proposed here has the potential to establish a new method to visualization Hg pollution in water and also could promote the application of PNCs in the detection of important targets in water environments.