PEAI Surface Treatment for Low Ion Migration and High-Performance FAPbBr₃ Single-Crystal X-ray Detectors

Area of Science:

• Materials Science
• Crystallography
• Radiation Detection

Background:

• Organometal halide perovskite single crystals (SCs) show promise for radiation detection.
• Surface defects in FAPbBr3 SCs hinder their performance and limit applications.

Purpose of the Study:

• Identify surface defects in FAPbBr3 SCs.
• Investigate the effects of phenethylammonium iodide (PEAI) surface treatment on ion migration, photoelectric performance, and X-ray detection.

Main Methods:

• Characterization of surface defect types in FAPbBr3 SCs.
• Application of PEAI solution for surface treatment.
• Evaluation of ion migration, carrier lifetime, trap density, and dark current.
• Measurement of X-ray detection performance.

Main Results:

• PEAI and 2D PEA2PbI4 layers effectively passivate metallic Pb and Br vacancies.
• PEAI treatment elongates carrier lifetime, reduces trap density, and suppresses ion migration.
• 2D PEA2PbI4 layers provide dense coverage, suppress ion migration, and lower dark current.
• PEAI-passivated FAPbBr3 SC detectors exhibit a tenfold increase in X-ray sensitivity.

Conclusions:

• Surface passivation is crucial for improving the quality and performance of perovskite SCs.
• PEAI treatment offers a viable strategy to enhance SCs for advanced radiation detection applications.