Nonplanar Perylene Monoimide‐Based Fluorescent Film for Enhanced BTX Sensing

Main observation and conclusion Film‐based fluorescent sensors have been adapted into portable devices for the vapor phase detection. The satisfactory sensing performance ( e.g ., sensitivity, selectivity, reusability) largely benefits from fluorophores. Here we report a new nonplanar perylene monoimide derivative (PMI‐CB) and demonstrate its application in a miniaturized film‐based fluorescent sensor for BTX ( i.e ., benzene, toluene, xylene) detection. The fluorophore of PMI‐CB is obtained through incorporating a three‐dimensional o ‐carborane with the perylene monoimide (PMI). Compared to a planar PMI derivative (PMIA), the nonplanar PMI‐CB with reduced intermolecular aggregation exhibits enhanced fluorescence intensities in both solvents and film state. The PMI‐CB film exhibited fluorescence enhancements for BTX, while fluorescence quenching for commonly interfering compounds like ethanol, triethylamine, and acetone. Such opposite response behavior endows the PMI‐CB‐based sensor with the ability for selective detection of BTX. Importantly, our PMI‐CB film is not sensitive to water. The sensitivity test shows that the PMI‐CB film can detect benzene vapor at a concentration of as low as 3.3 mg/m 3 without any preconcentration procedures, and exhibits a good linear relationship from 3.3 to 425.9 mg/m 3 . On the basis of this work, a portable detector with high selectivity, sensitivity, reusability, and low power consumption can be adapted for the on‐site BTX detection.