Ion Leakage Current Control for Polycrystalline Metal Halide Perovskite Direct X-ray Detectors

Area of Science:

• Materials Science
• Solid-State Physics
• Detector Technology

Background:

• Metal halide perovskites offer advantages for X-ray detection, including high X-ray attenuation and defect tolerance.
• High intrinsic ion conductivity in perovskites leads to challenges like high dark current and current drift, hindering detector performance.
• Developing strategies to manage ion conductivity is crucial for stable and sensitive perovskite X-ray detectors.

Purpose of the Study:

• To mitigate issues of high dark current and current drift in polycrystalline metal halide perovskite X-ray detectors.
• To enhance the sensitivity, stability, and response speed of perovskite-based X-ray detectors.
• To investigate the efficacy of 2,2,3,3,3-pentafluoropropylamine hydrochloride (PFH) as a performance-enhancing additive.

Main Methods:

• Incorporation of 2,2,3,3,3-pentafluoropropylamine hydrochloride (PFH) into polycrystalline MAPbI_3-Cl films.
• Utilizing a one-step blade-coating method for film fabrication.
• Analysis of PFH aggregation at grain boundaries and its effect on local vacuum energy levels and defect passivation.

Main Results:

• PFH addition effectively passivates surface defects and reduces ion conductivity without impacting electron conductivity.
• Significant reduction in dark current density and current drift was observed.
• Achieved a low X-ray detection limit of 14.7 nGy_air/s, demonstrating enhanced sensitivity.
• Improved signal stability, consistency, and response speed of the detectors.

Conclusions:

• PFH is a promising additive for polycrystalline metal halide perovskite X-ray detectors.
• The strategy of passivating grain boundaries with PFH effectively addresses ion conductivity issues.
• This approach holds potential for advancing the practical applications of perovskite X-ray detector technology.