Aggregation-induced emission of lead halide perovskites modulated by dispersed/aggregated gold nanoparticles for application in the detection of dopamine

A new kind of lead halide perovskites (LHPs) with aggregation induced emission (AIE) feature is developed. These LHPs are nonemissive when they disperse in good solvent (DMF), but show high brightness when they aggregate in water. The morphology of LHPs changes from nanometer-sized irregular shape to micrometer-sized needle-like, and then to stick-like with increasing water fraction. However, their AIE is quenched by only a few pM of dispersed gold nanoparticles (AuNPs). Dopamine (DA) induces aggregation of AuNPs, resulting in AIE recovery of LHPs. A good linear range of DA is obtained from 0.5 to 50 μM with the limit of detection (LOD) 0.12 μM. In the catalysis of tyrosinase (TYR), DA is oxidized to dopaquinone, resulting in the fluorescence quenching of LHPs again. Therefore, this system is further used for monitoring TYR activity and evaluating inhibitor of TYR. Finally, this method is successfully applied to detecting DA in urine samples.