Cascade Fluorescence Modulation in Photochromic Microcapsules

Area of Science:

• Photochemistry
• Materials Science
• Chemical Sensing

Background:

• Terarylene derivatives demonstrate efficient oxidative cycloreversion with quantum yields > 1, causing a color change.
• Previous systems using chloroform for radiation detection lacked wavelength selectivity and reusability.
• Nile Red enhances visual detection through fluorescence photoswitching.

Purpose of the Study:

• To develop a reusable, wavelength-selective system for detecting ionizing radiation.
• To integrate terarylene's cascade effect with Nile Red's fluorescence photoswitching.
• To achieve a single microencapsulated system exhibiting both phenomena.

Main Methods:

• Utilized chlorobenzene as a wavelength-selective solvent for photocyclization and cycloreversion.
• Incorporated Nile Red to enhance sensitivity via fluorescence photoswitching.
• Employed Pickering emulsion to microencapsulate terarylene and Nile Red.

Main Results:

• The terarylene-Nile Red system in microcapsules demonstrated high fatigue resistance for repeated photocyclization and cycloreversion.
• Achieved repeatable ON/OFF fluorescence photoswitching.
• Successfully demonstrated the cascade effect with fluorescence recovery, proving versatility in different media.

Conclusions:

• Microencapsulated terarylene-Nile Red systems offer a versatile platform for reusable, wavelength-selective photoswitching sensors.
• The combined cascade effect and fluorescence photoswitching provide a robust method for visual detection of radiation.
• This system shows significant potential for advanced optical sensing applications.