Cation Engineering Enhanced Moisture Resistance in Centimeter-Sized Lead-Free Halide Perovskite Crystal for...

Area of Science:

• Materials Science
• Solid-State Physics
• Detector Technology

Background:

• Halide perovskites are promising for X-ray detection due to their eco-friendliness and performance.
• Structural instability in moist environments limits the reliability of current lead-free perovskite X-ray detectors.

Purpose of the Study:

• To develop a moisture-resistant, lead-free halide perovskite for stable X-ray detection.
• To enhance the reliability and longevity of perovskite-based X-ray detector devices.

Main Methods:

• Cation engineering: substituted N-acidic protons with methyl groups of aniline to create (NDMA)3BiI6.
• Crystal growth: employed controlled solution cooling to grow centimeter-sized single crystals (up to 20 × 12 × 5 mm³).
• Device fabrication and testing: created X-ray detectors and evaluated their sensitivity, moisture resistance, and operational stability.

Main Results:

• Synthesized moisture-resistant lead-free halide perovskite (NDMA)3BiI6 with a water contact angle of 98.38°.
• Achieved retained phase integrity after 7-day water immersion and 1-year ambient storage.
• Fabricated X-ray detectors with high sensitivity (up to 2162 µC Gyair⁻¹ cm⁻²) and excellent operational stability (retaining 82% sensitivity after 5h water immersion).

Conclusions:

• Cation engineering successfully produced a humidity-resistant lead-free perovskite, (NDMA)3BiI6.
• The developed perovskite integrates high X-ray detection performance with enhanced stability, paving the way for reliable eco-friendly detectors.
• This work offers a viable strategy for advancing stable perovskite-based X-ray detection technologies.