The water-soluble red CsPbI3 perovskite quantum dot "on-off-on" fluorescence sensor for the detection of Cu2+ and D-penicillamine.

In this study, a water-soluble perovskite quantum dot (PQDs) based on CsPbI3 "on-off-on" fluorescent probe was successfully constructed. The probe exhibits red fluorescence emission at 660 nm under 465 nm excitation, and the response mechanism of Cu2+-induced fluorescence quenching (OFF) and D-penicillamine (D-PA) triggered fluorescence recovery (ON) is realized. In addition, the dual target detection platform of both copper ions (Cu2+) and D-PA was established. Quantitative analysis showed that the detection linearity range was 0.5-15 μM (LOD = 0.21 μM) for Cu2+ and 0.4-60 μM (LOD = 16.7 nM) for D-PA. Meanwhile, D-PA can be semi-quantitatively measured based on the change in solution color. The fluorescent probe provides a fast response time, high sensitivity, and convenient solution for real-time detection of Cu2+ and D-PA. And it was applied in the determination of D-PA in serum samples with satisfactory results. It is particularly noteworthy that the synthesized perovskite quantum dots exhibit excellent stability in the aqueous environment, which provides a new strategy for expanding the application of perovskite materials in the field of biomedical analysis.