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

Area of Science:

• Materials Science
• Chemical Sensing
• Photophysics

Background:

• Traditional organic luminogens suffer from aggregation-caused quenching (ACQ) and poor photochemical stability, limiting their use in solid-state sensors.
• There is a need for novel luminogens that exhibit aggregation-induced emission (AIE) and possess high stability for practical sensing applications.

Purpose of the Study:

• To develop a novel aggregation-induced emission luminogen (AIEgen) incorporating pyrene and o-carborane (CB-PY).
• To investigate the dual-phase emission, intramolecular charge transfer (ICT) properties, and photochemical stability of CB-PY.
• To evaluate the sensing performance of CB-PY for volatile organic compounds (VOCs).

Main Methods:

• Synthesis of a novel AIEgen, CB-PY, combining pyrene and o-carborane moieties.
• Characterization of photophysical properties, including luminescence quantum yields in solution and solid states.
• Assessment of photochemical stability under ambient conditions over an extended period.
• Fabrication of fluorescence test strips for VOC detection and evaluation of sensing performance (speed, reversibility, visual discrimination).

Main Results:

• CB-PY exhibits unique dual-phase emission in both solution and solid states, bridging the gap between ACQ and AIE phenomena.
• The luminogen demonstrates extraordinary photochemical stability, with negligible emission intensity attenuation after 4 months of ambient exposure.
• Fluorescence test strips based on CB-PY achieved fast, reversible, and visual discrimination of four organic solvents with varying polarities.
• CB-PY successfully discriminated different gasoline grades (92#, 95#, 98#) through distinct color changes under UV illumination.

Conclusions:

• The developed CB-PY is a highly stable AIEgen with dual-phase emission properties, suitable for robust sensing applications.
• CB-PY offers significant advantages over traditional luminogens, particularly in its resistance to aggregation-caused quenching and enhanced photochemical stability.
• The material shows great promise for the visual and selective detection of volatile organic compounds, including different fuel types.