Monodisperse Spherical Sandwiched Structured SiO2@CsPbX3@SiO2 Perovskite Composites for the Determination of Fe3+ Ion in Water Samples

The application of all-inorganic CsPbX3 (X = Cl−, Br− and I−) perovskite nanocrystals (PNCs) is hindered by their poor stability under different environments (moisture, UV light and high temperature). Herein, we demonstrate a novel in-situ growth and post-coating technique to prepare monodisperse spherical sandwiched structured SiO2@CsPbX3@SiO2 perovskite composites. In this strategy, the environmental stability of CsPbX3 PNCs is remarkably improved due to protecting evenly distribution in the surface of composites through the design of spherical sandwiched structure, and the negative effects of SiO2 coating on photoluminescence property of CsPbX3 PNCs could be reduced effectively. Furthermore, regular monodisperse spherical structure and uniform size of composites greatly benefit their application in relative fields. The experiment results indicate that the as-prepared product have outstanding abilities of water-, oxidation- and UV radiation resistance. Finally, the SiO2@CsPbBr3@SiO2 perovskite composites are successfully used for highly sensitive detection of Fe3+ in water sample. The results show limit of detection (LOD) is 3 µM and good linearity is between 10 and 70 µM (R2 = 0.9963). Furthermore, the proposed perovskite composites have been successfully applied for the analysis of Fe3+ in real samples with satisfactory results.