Sensitive and Stable 1D MDAPb₂I₆ Single-Crystal X-ray Detector with Anisotropic Response

Area of Science:

• Materials Science
• Solid-State Physics
• Crystallography

Background:

• Metal halide perovskites are promising for X-ray detection due to high atomic number and optoelectronic properties.
• Three-dimensional (3D) perovskites suffer from isotropic carrier transport, leading to signal cross-talk and reduced resolution.
• Ion migration in 3D perovskites causes dark current fluctuations and device instability.

Purpose of the Study:

• To synthesize high-quality, centimeter-size one-dimensional (1D) metal halide perovskite single crystals.
• To investigate the anisotropic carrier transport properties of 1D perovskites for X-ray detection.
• To evaluate the stability and performance of 1D perovskite detectors under X-ray irradiation.

Main Methods:

• Thermostatic metastable growth and continuous solute replenishment were employed for crystal synthesis.
• Anisotropy in carrier transport was studied by measuring detector performance along different crystallographic axes.
• Ion migration activation energy and dark current fluctuations were characterized.

Main Results:

• Centimeter-size, high-quality 1D MDAPb2I6 single crystals were successfully grown.
• Detectors along the c-axis exhibited a high sensitivity (0.65 × 10^4 μC Gyair^-1 cm^-2), suppressing lateral carrier diffusion.
• MDAPb2I6 crystals showed high ion migration activation energy (1.27 eV), leading to stable performance and low dark current fluctuations.
• A detection limit of 87.5 nGyair s^-1 was achieved, suitable for medical imaging.

Conclusions:

• 1D perovskite single crystals effectively suppress lateral carrier diffusion and signal cross-talk.
• The enhanced stability against ion migration makes 1D perovskites suitable for long-term, high-dose X-ray detection.
• This work provides a pathway for developing high-resolution and stable X-ray imaging detectors.