One-Step Coordinating POPD in H₃BTB-Sensitized EuMOF-Enabled Tunable Antenna Effects for Fluorescence Turn-On Sensing of Sarin Analogue Vapor

The structural modification of metal-organic frameworks (MOFs) is of vital importance in many fields, especially in sensing with enhanced performance, while the efficient synthesis of functionalized MOF nanoparticles toward small molecule detection remains challenging. Here, a general cellulose nanofibril (CNF)-induced in situ one-step strategy was proposed for the synthesis of dual-ligand-functionalized europium-based MOF (EuMOF@CNF) nanoparticles under an effective regulation of the crystallization kinetics in hydrothermal synthesis. Based on the unique dual-ligand structure, the obtained EuMOF featured a tunable antenna effect and laid a good foundation for fluorescence-sensing materials. Benefiting from the superior self-assembly properties of CNFs and the tunable antenna effect of EuMOF@CNF, flexible sensing films were constructed, showing excellent mechanical properties (72 MPa for stress and 3.8% for strain) and tunable luminescence properties and achieving instant (1 s) and sensitive fluorescence sensing of sarin analogue vapor with a significantly low limit of detection (LOD, 2.8 ppb) and robust selectivity against a wide range of common interferents (>14 types), especially independent of common acids. We believe that this pioneering design of EuMOF with tunable antenna effects would positively advance the development of high-performance MOF-based fluorescent materials and devices.