Charge transport manipulation of lead-free perovskite A₃Sb₂X₉ single crystal for stable and sensitive x-ray detection

Abstract

Compared with three-dimensional (3D) perovskites, low-dimensional perovskites can effectively enhance device stability and reduce leakage current due to the shielding effect of A-site cations and high resistivity, thus showing broad application prospects in the field of high-energy radiation detection. In this study, high-quality lead-free A₃Sb₂X₉ type single crystals (SCs) with large size are grown via a solution method. The manipulation mechanism of charge transport in these low-dimensional perovskite SCs by ion radius, coordination ability, and charge distribution characteristics is systematically investigated. Furthermore, the collaborative optimization mechanism of x-ray detection performance through crystal structure design and charge transport performance manipulation is elaborately revealed, which provides an important foundation for designing high-quality and low-toxicity perovskite SCs to achieve high signal-to-noise ratio (SNR) x-ray detectors. Therefore, under the premise of maintaining superior stability and high resistivity, the optimized lead-free low-dimensional perovskite SCs achieve comparable detection performance to that of lead-based perovskites. Specifically, the fabricated SC x-ray detectors exhibit high resistivity (10¹¹ Ω cm), large μτ product (7.9 × 10⁻³ cm² V⁻¹), high detection sensitivity (3073 μC Gy⁻¹ cm⁻²), ultra-low detection limit (0.37 nGy s⁻¹), and negligible dark current drift (6.8 × 10⁻⁸ nA cm⁻¹ s⁻¹ V⁻¹). This rare combination of superior properties enables the SC detector to achieve high-resolution (7.5 lp mm⁻¹) x-ray imaging.

Keywords

A₃Sb₂X₉ perovskite / carrier transport / lead-free / single crystal / x-ray detection

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