Bulk Heterostructure BA₂PbI₄/MAPbI₃ Perovskites for Suppressed Ion Migration To Achieve Sensitive X-ray Detection...

Area of Science:

• Materials Science
• Solid-State Physics
• Medical Imaging Technology

Background:

• Three-dimensional (3D) lead-halide perovskites offer high sensitivity for X-ray detection due to excellent mobility-lifetime products and photon attenuation.
• However, ion migration under electrical bias leads to dark-current drift and instability, hindering practical applications.

Purpose of the Study:

• To design and fabricate a bulk 2D/3D perovskite heterostructure to mitigate ion migration and dark current drift.
• To improve the stability and lower the detection limit of perovskite-based X-ray detectors for medical diagnostics.

Main Methods:

• A bulk 2D/3D perovskite heterostructure was synthesized by hot-pressing a mixture of BA2PbI4 (2D) and MAPbI3 (3D) particles.
• Resistivity, ion migration, and dark-current drift were measured and compared between the heterostructure and pure MAPbI3 pellets.
• X-ray sensitivity and detection limit were evaluated under an electrical bias.

Main Results:

• The bulk 2D/3D heterostructure exhibited significantly higher resistivity and reduced ion migration compared to pure MAPbI3.
• A substantially lower dark-current drift (4.84 × 10^-5 nA cm^-1 s^-1 V^-1) was observed in the heterostructure.
• The heterostructure achieved high X-ray sensitivity (2.0 × 10^3 μC Gyair^-1 cm^-2) and a low detection limit (111.76 nGy s^-1).

Conclusions:

• The bulk 2D/3D perovskite heterostructure effectively suppresses ion migration and dark current drift.
• This strategy enhances the stability and performance of lead-halide perovskite X-ray detectors.
• The developed material holds promise for advancing X-ray diagnostics with improved sensitivity and reliability.