Spirooxazine-Based Solid-State Photoswitchable Fluorescent Materials for Advanced Time-Resolved Anti-Counterfeiting

Area of Science:

• Materials Science
• Photochemistry
• Organic Chemistry

Background:

• Photoswitchable fluorescent materials offer tunable, high-contrast fluorescence valuable for anticounterfeiting.
• Solid-state photoswitching remains a significant challenge in material design.

Purpose of the Study:

• To design and synthesize a novel solid-state photoswitchable fluorescent compound.
• To investigate its photoresponsive properties and potential for anticounterfeiting applications.

Main Methods:

• Covalent linkage of spirooxazine (SO) and tetraphenylethene (TPE) moieties to create SO-TPE.
• Characterization of solid-state photoswitching behavior under UV and visible light irradiation.
• Spectroscopic analysis (fluorescence decay) and theoretical calculations to elucidate mechanisms.

Main Results:

• SO-TPE exhibits reversible absorption and fluorescence modulation in the solid state.
• UV exposure induces color change (light yellow to blue gray) and fluorescence switching (cyan to nonemission).
• Mechanism involves photoisomerization of SO and intramolecular energy transfer between TPE and SO moieties.

Conclusions:

• The designed SO-TPE compound is an effective solid-state fluorescent switch.
• The strategy provides a pathway for advanced photoresponsive materials.
• Potential applications include high-security anticounterfeiting and information encryption using Morse code.