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 FL spectra of the PNCs probes can be adjusted by controlling the concentration of KI in anion exchange to improve the detection selectivity of AA. The high sensitivity and selectivity make CsPb(Br/I)3 PNCs an ideal material for AA sensing. The concentration of AA can be linearly measured in the range from 0.01 to 50 mu M, with a detection limit of 4.2 nM. The reason for the enhanced FL of CsPb(Br/I)3 PNCs was studied, and it is considered that AA causes the aggregation of CsPb(Br/I)3 PNCs. This strategy of improving the selectivity of the probe to the substrate by adjusting the spectrum will significantly expand the application of PNCs in the field of analysis and detection.