Achieving Persistent, Efficient, and Robust Room-Temperature Phosphorescence from Pure Organics for Versatile...

Area of Science:

• Materials Science
• Organic Chemistry
• Photophysics

Background:

• Pure organic persistent room-temperature phosphorescence (p-RTP) is highly desirable but difficult to achieve due to challenges with intersystem crossing and triplet exciton stability.
• Developing organic luminogens with both high efficiency and long lifetimes is complicated by conflicting requirements for the T1 energy states.

Purpose of the Study:

• To design and synthesize novel amide-based organic molecules capable of efficient and robust p-RTP under ambient conditions.
• To investigate the photophysical properties, mechanical robustness, and potential applications of these new p-RTP materials.

Main Methods:

• Incorporation of spin-orbital-coupling-promoting groups (carbonyl and aromatic π units) into amide-based molecular structures.
• Characterization of photoluminescence properties, including phosphorescence lifetime and efficiency.
• Assessment of material robustness through mechanical stimulation and evaluation in amorphous states.
• In vivo bioimaging studies using live mice to demonstrate afterglow imaging capabilities.

Main Results:

• Developed amide-based derivatives exhibiting efficient p-RTP with lifetimes up to 710.6 ms and efficiencies of 10.2%.
• Demonstrated remarkable robustness, with two compounds showing intense p-RTP after vigorous mechanical stimulation.
• Achieved an ultrahigh signal-to-background ratio of 428 in in vivo afterglow imaging, highlighting the material's benefit for biological applications.
• Confirmed efficient and robust p-RTP even in the amorphous state.

Conclusions:

• The synthesized amide-based compounds offer a promising route to efficient and robust pure organic p-RTP materials.
• These materials overcome previous limitations, enabling applications in areas like anti-counterfeiting and advanced bioimaging without complex protective measures.
• The findings pave the way for versatile applications of stable organic phosphorescent materials.