Highly Electrochemiluminescent CsPbBr@CsPbBr 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 PbBr, 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 (CsPbBr) and 0D PQDs (CsPbBr) with unique morphologies, i.e., CsPbBr@CsPbBr PQD nanoacanthospheres (PNAs), in which CsPbBr was as the core and CsPbBr served as the shell. The obtained CsPbBr@CsPbBr PNAs had much higher (>4 times) ECL activity than the prevailing 3D (CsPbBr) PQDs. Finally, the novel CsPbBr@CsPbBr PNAs have been applied for the ECL sensing of bisphenol A (BPA), showing a promising application of the highly electrochemiluminescent PQDs in analytical chemistry.