Cryogenically Flexible Phosphorescent Organic Crystals that Transmit Self-Sustained Persistent Luminescence with...

Area of Science:

• Materials Science
• Organic Chemistry
• Solid-State Physics

Background:

• Achieving simultaneous long-lived phosphorescence and cryogenic elasticity in soft matter is challenging due to opposing low-temperature effects on molecular motion.
• Low temperatures typically enhance phosphorescence but compromise elasticity, causing brittleness in soft materials.

Purpose of the Study:

• To investigate organic crystals as a potential solution for overcoming the disparity between phosphorescence and elasticity at low temperatures.
• To report on an organic crystalline material demonstrating exceptional elasticity and ultralong phosphorescence at cryogenic temperatures.

Main Methods:

• Synthesis and characterization of triphenylene as an organic crystalline material.
• Evaluation of mechanical properties (elasticity) at 77 K.
• Measurement of phosphorescence lifetime at low temperatures.

Main Results:

• Triphenylene crystals exhibit remarkable elasticity at 77 K and an ultralong phosphorescence afterglow of up to 30 seconds.
• The material's molecular rigidity and dense packing facilitate reversible lattice deformation and mechanical robustness upon cooling.
• Crystals function as dynamic phosphorescent waveguides, maintaining emission in low-temperature, dark conditions.

Conclusions:

• Organic crystals, exemplified by triphenylene, can reconcile long-lived phosphorescence and cryogenic elasticity.
• This material offers a novel platform for flexible, lightweight optical devices and sensors capable of functioning in extreme environments.
• Potential applications include time-encoded biological information transmission using sustained optical signals.