Fluorescence Light‐Up Electrospun Membrane Incorporated with PbBr2 as a Highly Selective Fluorescence Probe for the Detection of Cs

This study introduces a novel fluorescent light‐up electrospun membrane, integrating PbBr2, which serves as an exceptionally selective probe for the detection of cesium ions (Cs+). Leveraging the superior optical properties of CsPbBr3 perovskite nanocrystals (PNCs), the researchers employ electrospinning technology to fabricate a test strip, namely PbBr2@polyacrylonitrile (PbBr2@PAN) nanofiber membranes, capable of swiftly detecting Cs+ in water merely by observing changes in the nanocrystals' luminescence with the naked eye. By the introduction of NH4+‐modified montmorillonite (NH4+‐MMT), PbBr2‐MT@PAN nanofiber membranes is obtained. The selectivity and sensitivity to Cs+ can be further improved because NH4+‐MMT endows PbBr2‐MT@PAN nanofiber membranes with the hydrophilic property and selective adsorption toward Cs+ ions. The membrane's fabrication is simple, scalable, and cost‐effective, with high cesium selectivity and sensitivity down to 44 ppb. This innovation enables efficient, on‐site cesium monitoring critical for environmental safety and nuclear waste management. This study presents a novel PbBr2‐MMT@PAN electrospinning membrane for selective Cs+ detection, which can be attributed to the luminescent CsPbBr3 perovskite nanocrystals. The incorporation of NH4+‐MMT into the PbBr2‐MMT@PAN nanofiber membrane can further enhance its hydrophilicity and selective adsorption of Cs+ ions, enabling rapid detection of cesium ions with a detection limit of 44 ppb.