Highly Electrochemiluminescent Cs₄PbBr₆@CsPbBr₃ Perovskite Nanoacanthospheres and Their Application for Sensing Bisphenol A

Perovskite quantum dots (PQDs) as recently emerging electrochemiluminescence (ECL) luminophores have been paid much attention due to their good ECL activity, narrow ECL spectra, and easy preparation. However, the PQDs used for ECL sensing were mainly inherited from those PQDs prepared as strong fluorescence (FL) luminophores, which would limit the finding of highly ECL PQDs for sensing due to the very different mechanisms in generating excited-state luminophores between ECL and FL. In order to obtain highly electrochemiluminescent PQDs, for the first time we proposed to synthesize PQDs for ECL sensing rather than for FL-based analysis by optimizing the synthesis conditions. It was revealed that the volume of the precursor solution, the concentrations of CsBr and PbBr2, the amount of capping reagents, and the synthesis reaction temperature all significantly affect the ECL activity of PQDs. On the basis of the optimization of the synthesis conditions, we obtained a new type of PQDs with high ECL activity. The new PQDs were characterized by several technologies, such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and energy dispersive X-ray spectrum, to be the hybrids of 3D PQDs (CsPbBr3) and 0D PQDs (Cs4PbBr6) with unique morphologies, i.e., Cs4PbBr6@CsPbBr3 PQD nanoacanthospheres (PNAs), in which Cs4PbBr6 was as the core and CsPbBr3 served as the shell. The obtained Cs4PbBr6@CsPbBr3 PNAs had much higher (>4 times) ECL activity than the prevailing 3D (CsPbBr3) PQDs. Finally, the novel Cs4PbBr6@CsPbBr3 PNAs have been applied for the ECL sensing of bisphenol A (BPA), showing a promising application of the highly electrochemiluminescent PQDs in analytical chemistry