Selective detection of ascorbic acid by tuning the composition and fluorescence of the cesium lead halide perovskite nanocrystals.

Lead halide perovskite nanocrystals (PNCs) have attracted intense attention due to their excellent optoelectronic properties. In this work, a series of water-stable CsPb(Br/I)3 PNCs fluorescent probes were prepared using an anion exchange method. It was found that the PNCs probes could be used to detect ascorbic acid (AA) in water, and interestingly, the selectivity for AA detection could be improved by adjusting the FL spectra of the PNCs probes by controlling the concentration of KI in anion exchange. The high sensitivity and selectivity characteristics make CsPb(Br/I)3 PNCs ideal materials for AA sensing. The concentration of AA in the range from 0.01 to 50 µM can be linearly measured with a limit of detection of 4.2 nM The reason for the enhanced FL of CsPb(Br/I)3 PNCs was studied and concluded to be the aggregation of CsPb(Br/I)3 PNCs caused by AA. This strategy of improving the selectivity of the probe to the substrate by adjusting the spectrum will greatly expand the application of PNCs in the field of analysis and detection.