Ligand Confinement for Fast-Decay Cu─I Chain Scintillators Enabling High-Resolution X-ray Imaging and 3D Tomography

Area of Science:

• Materials Science
• Solid-State Chemistry
• Nanotechnology

Background:

• One-dimensional (1D) copper(I) iodide cluster complexes offer potential as scintillators due to their X-ray absorption and stability.
• However, their emission efficiency is limited compared to zero-dimensional (0D) materials.

Purpose of the Study:

• To enhance X-ray Excited Luminescence (XEL) and accelerate decay dynamics in 1D Cu-I cluster scintillators.
• To establish a ligand-confinement strategy for improved scintillator performance.

Main Methods:

• Employed sterically hindered, electronically tuned pyrimidine-based bridging ligands.
• Utilized rigid, compact bidentate ligands to increase structural rigidity and reduce organic fraction.
• Introduced asymmetric substituents to induce coupled spatial and electronic confinement, forming quantum-wire-like electronic states.

Main Results:

• Achieved a six-fold enhancement in photoluminescence quantum yield for CuI(4-Mepym) compared to CuI(2-Mepym).
• Observed a fast decay lifetime of 1.28 µs, surpassing most reported Cu-I cluster complexes.
• Demonstrated high stability, solution processability, and a light yield comparable to commercial LuAG:Ce (~25,000 ph MeV⁻¹).

Conclusions:

• The ligand-confinement strategy effectively boosts brightness and speed in 1D Cu-I cluster scintillators.
• CuI(4-Mepym) overcomes the conventional brightness-speed trade-off, enabling high-resolution static and dynamic X-ray imaging.
• This work provides a new design principle for developing advanced scintillators for high-fidelity X-ray applications.