Ultra-Broad Emission Copper Halide Scintillator-Based X-Ray Imager

Area of Science:

• Materials Science
• Solid-State Physics
• Radiological Imaging

Background:

• Lead-free scintillators are sought as eco-friendly alternatives to lead-based ones.
• Broad-emission scintillators compatible with photodetectors are less explored.
• CsI:Tl is a state-of-the-art scintillator but requires further investigation.

Purpose of the Study:

• To develop a novel lead-free metal-halide scintillator with ultra-broad emission.
• To investigate the optical properties and emission mechanism of the new scintillator.
• To demonstrate its application in high-resolution X-ray imaging.

Main Methods:

• Synthesis and characterization of TPA2Cu2I4 (TPACI) copper halide scintillator.
• Optical property analysis including photoluminescence quantum yield and light yield.
• Mechanism analysis of ultra-broad emission attributed to dual self-trapped excitons (STE).
• Assembly and testing of a TPACI scintillator-based X-ray imager prototype.

Main Results:

• TPACI exhibits unique ultra-broad emission (FWHM > 240 nm) compatible with commercial photodetectors.
• Dual STE emission is identified as the mechanism for the broad spectrum.
• High photoluminescence quantum yield (94.27%) and light yield (≈40124 photons MeV-1) were achieved.
• The TPACI-based X-ray imager demonstrated high resolution (5.5 lp mm-1 at MTF=0.2).

Conclusions:

• TPACI is an efficient, self-absorption-free scintillator with excellent white light emission.
• The dual STE mechanism provides a pathway for designing broad-emission scintillators.
• TPACI shows great potential for high-resolution X-ray imaging applications in biological and electronic fields.