Highly Sensitive and Stable X-ray Detector Based on a 0D Structural Cs₄PbI₆ Single Crystal

Area of Science:

• Materials Science
• Solid-State Physics
• Crystallography

Background:

• Lead halide perovskites are promising for X-ray detection due to high stopping power and large mobility-lifetime (μτ) product.
• However, their practical application is hindered by poor air stability and ion migration, leading to device degradation.
• Developing robust perovskite materials is crucial for advancing X-ray detector technology.

Purpose of the Study:

• To develop a solution-processed, air-stable lead halide perovskite single crystal for X-ray detection.
• To investigate the properties and X-ray detection performance of a zero-dimensional (0D) bulk Cs4PbI6 single crystal.
• To evaluate the long-term stability of the fabricated X-ray detector under ambient conditions.

Main Methods:

• Synthesis of a solution-processed 0D bulk Cs4PbI6 single crystal with isolated [PbI6]4- units.
• Fabrication of a photoconductor device using a symmetric Au/Cs4PbI6/Au sandwich structure.
• Characterization of the crystal's electrical properties (μτ product, activation energy) and device performance under X-ray irradiation.

Main Results:

• The 0D Cs4PbI6 single crystal exhibited a high mobility-lifetime (μτ) product of 9.7 × 10⁻⁴ cm² V⁻¹ and an activation energy of 321.28 meV.
• The fabricated photoconductor device showed a high sensitivity of 451.49 μC Gy⁻¹ cm⁻² under 30 keV X-ray irradiation at 30 V.
• The device maintained nearly its original sensitivity after three months of storage in air at room temperature, demonstrating excellent air stability.

Conclusions:

• The developed 0D Cs4PbI6 perovskite single crystal offers a promising alternative to conventional X-ray detection materials.
• Its superior air stability and retained high sensitivity address critical limitations of existing perovskite-based detectors.
• This material holds significant potential for the development of practical and durable X-ray detection devices.