Revealing the Sensitivity-Stability Trade-Off in Quasi-2D Perovskite Single-Crystal X-ray Detectors

Area of Science:

• Materials Science
• Solid-State Physics
• Detector Technology

Background:

• Quasi-2D perovskites (Q2D PVSKs) offer environmental robustness and reduced dark current for X-ray detection.
• Tuning the phase n-value (number of inorganic layers) in Q2D PVSKs allows for balancing electronic and ionic properties.

Purpose of the Study:

• To systematically investigate how the phase n-value influences the performance and stability of Q2D PVSK X-ray detectors.
• To establish a quantitative understanding of the trade-off between sensitivity and operational stability as a function of dimensionality.

Main Methods:

• Fabrication and characterization of X-ray detectors using FPEA2MAn-1PbnI3n+1 single crystals with n = 1-3.
• Quantitative measurement of detector sensitivity and operational stability under varying phase n-values.

Main Results:

• Detector sensitivity increased from 28.9 to 55.2 μC Gy-1 cm-2 as n increased from 1 to 3.
• Improved sensitivity is linked to enhanced X-ray absorption, narrower bandgaps, better mobility-lifetime products, and reduced radiative recombination.
• Ion-migration activation energy decreased from 0.85 to 0.55 eV, leading to a threefold increase in current drift.

Conclusions:

• The phase n-value is a critical parameter dictating the sensitivity-stability trade-off in Q2D PVSK X-ray detectors.
• Optimizing dimensionality via the phase n-value provides a design principle for high-performance and stable X-ray detector devices.