Robust Fluorescent Nanofilm Toward High‐Performance Detection of Nerve Agent Simulant Diethyl Chlorophosphate and Sarin

Integrating smart detection functionality into mechanically robust films is essential for developing high‐performance flexible sensors, yet it remains challenging. Herein, we develop a robust fluorescent nanofilm sensor via dynamic condensation of acylhydrazone bonds at the airliquid interface. The resultant TPE‐HP nanofilm exhibits favorable mechanical properties with puncture resistance strength up to 0.60 kN mm −1 and fatigue resistance over 50 cycles. Benefiting from a photoluminescence quantum yield of 29.7% and visual color changes, the nanofilm serves as a flexible fluorescent sensor for the detection of chemical warfare agents. Integrated into a compact sensing platform, the laminated nanofilm sensor enables rapid and reversible detection of diethyl chlorophosphate with a limit of 0.132 ppt and full reversibility over 100 cycles. Reliability was further verified by double‐blind field tests. The intrinsic sensing mechanism was rationalized as the formation of phosphorylated intermediates and subsequent protonation of the acylhydrazone bonds. For a real nerve agent, Sarin, the TPE‐HP nanofilm sensor achieves practical detection limits of 1.0 mM in solution and 40.0 µg cm −3 in the gas‐phase. This work not only combines high‐performance fluorescence detection into a robust nanofilm, but also achieves a field‐deployable sensing prototype toward organophosphorus nerve agents.