Intermolecular Aggregation-Induced Delayed Fluorescence Scintillators for Ultrahigh-Resolution X-Ray Imaging.

Area of Science:

• Materials Science
• Organic Electronics
• Radiological Physics

Background:

• Organic X-ray scintillators (OXSTs) offer promise for radiation detection and medical imaging due to their properties.
• Aggregation-caused quenching (ACQ) hinders efficient solid-state emission and exciton utilization in OXSTs.

Purpose of the Study:

• To introduce a novel intermolecular aggregation-induced delayed fluorescence (AIDF) strategy to overcome ACQ.
• To develop high-performance OXSTs for advanced radiation detection and imaging applications.

Main Methods:

• Designed and synthesized a tailored emitter exhibiting aggregation-induced emission and thermally activated delayed fluorescence (TADF).
• Incorporated the emitter into a polysulfone host to create composite films.
• Evaluated the radioluminescence properties, exciton utilization, and X-ray imaging performance.

Main Results:

• The developed emitter demonstrated efficient intermolecular AIDF with sub-microsecond delayed lifetimes.
• Composite films showed bright, stable radioluminescence with significant resistance to concentration quenching.
• Achieved an ultralow detection limit (0.255 µGy s⁻¹) and high spatial resolution (20.0 lp mm⁻¹).

Conclusions:

• The intermolecular AIDF strategy effectively circumvents ACQ, enabling efficient exciton harvesting.
• The developed OXSTs outperform many organic and some inorganic counterparts in sensitivity and resolution.
• This work provides a molecular design paradigm for high-resolution, thin-film scintillators for medical imaging.