Dual-Phase Emission AlEgen with ICT Properties for VOC Chromic Sensing

In a film-based fluorescence sensor, luminogens are of vital importance since they play the role of probes or indicators. Traditional organic luminogens like pyrene show high luminescence quantum yields in dilute solutions, but their applications are usually limited by the aggregation-caused quenching (ACQ) effect and bad photochemical stability. Thus, this paper reports a novel aggregation-induced emission luminogen (AlEgen) containing both pyrene and o-carborane (CB-PY), which possesses unique dual-phase emission both in solution and solid state and intramolecular charge transfer (ICT) properties, fulfilling the gap between ACQ and AIE compounds. Importantly, the fluorophore presents extraordinary stability that there was almost no attenuation in the emission intensity of CB-PY in the solid state after 4 months of exposure at ambient conditions. It is these merits that make CB-PY exhibit outstanding sensing performances for volatile organic compounds (VOCs), where the fluorescence test strip shows fast, reversible, and visual discrimination of four organic solvents with varied polarities. Moreover, 92(#), 95(#), and 98(#) gasolines could be discriminated with CB-PY, showing different colors under UV illumination.

Automated summary

The study introduces a novel fluorescence sensor CB-PY which exhibits dual-phase emission characteristics and excellent stability in solid-state, making it suitable for sensing volatile organic compounds (VOCs) with fast, reversible, and visual discrimination of different organic solvents. Additionally, CB-PY can discriminate between 92(#), 95(#), and 98(#) gasolines based on the different colors they exhibit under UV illumination.