Detection of Fe (III) using APTES-coated CsPbBr3–CsPb2Br5 perovskite quantum dots

Perovskite materials consisting of dual-phase CsPbBr3–CsPb2Br5 coated with (3-Aminopropyl) tiethoxysilane (APTES) were synthesized using the ligand-assisted reprecipitation method at 0 °C. The photoluminescence intensity of CsPbBr3–CsPb2Br5 coated with APTES was 1.2 times higher than that of uncoated CsPbBr3–CsPb2Br5. Furthermore, the photoluminescence intensity of the synthesized perovskite materials remained at 95% of the initial emission intensity after 10 days in ethanol. Fe3+ ions were found to exert strong fluorescence quenching on the prepared CsPbBr3–CsPb2Br5 coated with APTES, and that effect originated from the decomposition of CsPbBr3 to CsPb2Br5. The quenching behavior was related to the adsorption between Fe3+ ions and APTES. The response time for detecting Fe3+ was only 8 s at 40 °C, indicating a high detection speed. Effective detection ranges for Fe3+ ions were achieved at concentrations between 10−2 and 10−5 M, and the detection limit was reached at 10−5 M with 89.6% of the initial emission intensity. These results revealed that the detection of Fe3+ ions using CsPbBr3–CsPb2Br5 coated with APTES exhibited high sensitivity as well as a short response time in a wide detecting range.