A state-switchable TADF macrocycle for multi-analyte sensing and hydrogen gas-driven emission enhancement

Area of Science:

• Materials Science
• Photochemistry
• Supramolecular Chemistry

Background:

• Photochemical sensing requires chromophores that modulate optical properties without structural changes.
• Thermally activated delayed fluorescence (TADF) materials offer unique photophysical properties for advanced applications.

Purpose of the Study:

• To introduce CPCQ, a TADF-active macrocycle, as a responsive platform for optical sensing.
• To investigate the adaptive emission mechanisms of CPCQ in response to various guests.

Main Methods:

• Synthesis and characterization of the CPCQ macrocycle.
• Photophysical studies including photoluminescence quantum yield (PLQY) and lifetime measurements.
• Investigation of guest-host interactions and their effect on emission properties.

Main Results:

• CPCQ exhibits high PLQY (78%) and a delayed lifetime of 243 ns.
• Reversible emission switching observed: electron-deficient guests reduce fluorescence, while electron-rich guests enhance delayed fluorescence.
• Oxygen quenches charge-transfer emission, restoring blue-shifted locally excited (LE) emission.
• Hydrogen significantly enhances LE emission (PLQY = 93%), suggesting potential superradiance.

Conclusions:

• CPCQ acts as a sensitive and selective molecular tool for optical sensing.
• The reversible state switching of its emission mechanism offers a novel approach for analyte detection.
• CPCQ shows promise for next-generation sensing and optoelectronic devices.