Suppressing Ion Migration in Heterostructure Single Crystals for Highly Sensitive Ultra-Stable X-Ray Detection

Area of Science:

• Materials Science
• Crystallography
• Optoelectronics

Background:

• Heterostructure single crystals are promising for optoelectronic devices.
• Ion migration in materials can hinder X-ray detection performance.
• Structural modifications are key to enhancing material stability.

Purpose of the Study:

• To synthesize a novel layered heterostructure single crystal.
• To investigate the crystal's potential for suppressing ion migration.
• To evaluate the material's performance in X-ray detection applications.

Main Methods:

• Gradual modification of cyclohexylmethylamine cation to 4-aminomethyltetrahydropyran cation.
• Synthesis of the layered heterostructure single crystal (PbCl₂)₂(4-Aminomethyltetrahydropyran)₂PbCl₄.
• Characterization of crystal structure, ion migration activation energy, and dark current drift.
• Fabrication and testing of X-ray detectors using the synthesized crystal.

Main Results:

• A stable layered heterostructure single crystal with perovskite and intergrowth layers was obtained.
• Organic components anchored via Pb─O bonds effectively suppressed ion migration (1.64 eV activation energy, 2.86 × 10⁻¹⁸ A cm⁻¹ V⁻¹ s⁻¹ dark current drift).
• X-ray detectors showed high sensitivity (8453.3 µC Gy⁻¹ cm⁻²), low detection limit (5.2 nGy s⁻¹), and excellent air stability (≈1 year).

Conclusions:

• The developed heterostructure single crystal exhibits superior stability and suppressed ion migration.
• The material demonstrates outstanding performance for high-performance X-ray detection.
• This work advances the application of heterostructure single crystals in optoelectronics.