APTES and CTAB Synergistic Induce a Heterozygous CsPbBr₃/Cs₄PbBr₆ Perovskite Composite and its Application on the Sensitive Fluorescent Detection of Iodide ions

Recently, all-inorganic halide perovskite quantum dots (IPQD) as a new fluorescent material with excellent fluorescence properties have attracted wide attention. However, their instability in polar solvents is the main factor hindering their application in analysis. Herein, a heterozygous perovskite (CsPbBr₃/Cs₄PbBr₆) was simultaneously prepared and stabilized by a silylanization strategy using (3-aminopropyl)-triethoxysilane (APTES) and cetyltrimethyl ammonium bromide (CTAB) assisted precipitation encapsulation method. The synthesized CsPbBr₃/Cs₄PbBr₆ emitted an independent fluorescence at 520 nm. The obtained CsPbBr₃/Cs₄PbBr₆ exhibited good stability in ethanol/water mixtures. It was used as a fluorescent probe for sensitively detecting iodide ions (I⁻) by fluorescence quenching mechanism in the concentration range of 1 ~ 70.0 µM with the detection limit (LOD) of 0.83 µM (relative standard deviation (RSD) = 1.33%, n = 20). The simplicity and high selectivity of the proposed fluorescent analysis method were the prominent features. This work could be extended to the other target ion detection by a perovskite fluorescent quenching.