Sr-doped perovskite quantum dots encapsulated in mesoporous silica for highly sensitive and selective detection of p-nitrophenol

Perovskite materials exhibit significant potential in optoelectronic devices, biomedical applications, and fluorescent probes. However, their inherent sensitivity poses substantial challenges to practical implementation. In this study, we synthesized strontium-doped perovskite quantum dot (CsPbBr₃:Sr QDs) nanocomposites (CsPbBr₃:Sr QDs/MSNs) via an in-situ crystal growth method and encapsulated them within mesoporous silica nanospheres to mitigate the limitations of CsPbX₃ QDs in aqueous and polar environments. When dispersed in aqueous solutions for over one month, these nanocomposites demonstrated minimal changes in fluorescence characteristics. Under more stringent conditions (acidic, basic, and elevated temperature environments), the novel perovskite-based inorganic/organic hybrid nanocomposites exhibited superior fluorescence stability. By introducing amino functionalization, the CsPbBr₃:Sr QDs/MSNs-NH₂ achieved selective and stable detection of p-nitrophenol (p-NP), a priority pollutant in water. Due to the inner filter effect (IFE) induced fluorescence quenching mechanism, p-NP exhibited high sensitivity and selectivity within the 0–300 μM range, with a detection limit of 0.74 μM. Furthermore, analysis of actual water samples confirmed that this method offers high recovery rates and low relative standard deviations. This work underscores the promising potential of perovskite-based nanocomposites as effective fluorescent probes for water quality analysis.