One-pot synthesis of highly stable CsPbBr₃@C6H7NO3S composite and its application in nitrite fluorescent sensing.

Herein, we introduced anhydrous 4-aminobenzene sulfonic acid (C6H7NO3S) to passivate the ligands on the surface of CsPbBr3 quantum dots, thereby synthesising a perovskite composite with excellent dispersion and stability in water via a one-pot process, namely CsPbBr3@C6H7NO3S composite. The fluorescence attenuation of CsPbBr3@C6H7NO3S composite was only 2.20 % after 5-day immersion in water, and the CsPbBr3@C6H7NO3S composite maintained excellent luminescence performance in long-term storage (4 months). The CsPbBr3@C6H7NO3S composite was then adopted to construct the fluorescent sensing for the detection of nitrite. Results showed that the fluorescence intensity had a linear relationship with the nitrite concentration in the range of 0.01-50.00 μM, with a detection limit of 3.30 nM. Meanwhile, the detection mechanism was discussed in detail. This work not only provides a sensitive sensing method for the detection of nitrite, but also provides a simple and effective strategy for the synthesis of perovskite.