High-Performance and Stable Perovskite X-ray Detection and Imaging Based on a Ti Cathode

Area of Science:

• Materials Science
• Detector Physics
• Solid-State Chemistry

Background:

• High-energy radiation detectors require high electric fields for optimal performance, but ion migration in perovskite materials limits their stability.
• Electrochemical reactions at the electrode-perovskite interface trigger ion migration, hindering detector reliability under high electric fields.

Purpose of the Study:

• To investigate the suppression of ion migration in organic-inorganic hybrid perovskite radiation detectors.
• To enhance the operating stability of these detectors under high electric fields using a novel electrode material.

Main Methods:

• Time-of-flight secondary-ion mass spectrometry (ToF-SIMS) was used to analyze ion migration.
• X-ray photoelectron spectroscopy (XPS) was employed to study the interface chemistry.
• Fabrication and testing of perovskite radiation detectors with a titanium (Ti) cathode.

Main Results:

• Ion migration was effectively suppressed in devices featuring a Ti cathode, even at electric fields of 50 V mm^-1.
• The formation of Ti-N bonds at the MAPbBr₃ perovskite/Ti electrode interface inhibited electrochemical reactions.
• The Ti-electrode device demonstrated high sensitivity (96 ± 1 mC Gy_air^-1 cm^-2) and a low detection limit (2.8 ± 0.3 nGy s^-1) for hard X-rays.

Conclusions:

• Titanium cathodes significantly improve the operational stability of perovskite-based radiation detectors under high electric fields.
• The Ti-N bond formation is crucial for preventing detrimental electrochemical reactions at the interface.
• These findings pave the way for more robust and sensitive perovskite radiation detectors.