Constructing Organic Phosphorescent Scintillators with Enhanced Triplet Exciton Utilization Through Multi-Mode...

Area of Science:

• Materials Science
• Organic Electronics
• Radiological Physics

Background:

• Organic phosphorescent scintillators are crucial for X-ray detection but face challenges with low exciton utilization efficiency.
• The spin-forbidden nature of X-ray-induced triplet excitons limits energy conversion in conventional organic scintillators.

Purpose of the Study:

• To design and develop novel organic phosphorescent scintillators with enhanced exciton utilization efficiency for X-ray detection.
• To overcome the limitations of spin-forbidden triplet excitons through a novel exciton release mechanism.

Main Methods:

• A design strategy involving thermally activated exciton release was employed.
• Conversion of spin-forbidden triplet excitons to spin-allowed singlet excitons was achieved.
• Simultaneous multi-mode emission from singlet and triplet states was enabled.

Main Results:

• The developed organic phosphorescent scintillators achieved a maximum photoluminescence efficiency of 65.8%.
• A minimum X-ray radiation detection limit of 110 nGy s⁻¹ was recorded.
• Efficient radiography imaging with a spatial resolution of approximately 10.0 lp mm⁻¹ was demonstrated.

Conclusions:

• The study advances the understanding of exciton dynamics in organic scintillators under X-ray excitation.
• The developed materials show significant potential for applications in safety-critical industries and medical diagnostics.
• Thermally activated exciton release offers a viable pathway for high-performance organic phosphorescent scintillators.