Lone‐pair Electrons Enhancement Effect: SnTe₃O₈ Hard X‐ray Detection with Stable High‐temperature Sensitivity and Ultralow Detection Limit

Abstract

Sensitivity and detection limit of X‐ray detectors are crucial for security checks, medical diagnoses, and industrial inspections. In this study, it is reported that introducing some cations containing lone‐pair electrons is beneficial for enhancing the Compton scattering effect and thus improving X‐ray detection performance. As an example, SnTe3O8 is selected and grown as a novel high‐temperature X‐ray detection crystal. Because of the high resistivity of 2 × 1014 Ω cm and high mobility lifetime product of 3.22 × 10−4 cm2 V−1, SnTe3O8 X‐ray detector exhibits a high sensitivity of 436 µC Gyair−1 cm−2 under 120 keV hard X‐ray, a low dark current drift of 2.44 × 10−9 nA cm−1 s−1 V−1 and a record low detection limit of 8.19 nGyair s−1 among all oxide X‐ray detectors. Furthermore, the high‐temperature sensitivity of SnTe3O8 X‐ray detector is enhanced to 617 µC Gyair−1 cm−2 at 175 °C, which is ≈31 times larger than that of the commercial α‐Se. The high thermal stability and stable high‐temperature sensitivity of SnTe3O8 single crystal X‐ray detectors have potential applications in high‐temperature environments. The results not only provide an excellent high‐temperature X‐ray detection crystal but also propose an effective method to explore X‐ray detector materials with excellent performances.

Two-dimensional lead-free perovskite Cs3Bi2I8.3Br0.7 single crystals with anisotropic ion migration and hard X-ray responses

“…X-ray detection has been widely used in the fields of space exploration, medical X-ray imaging, and scientific research. 1–6 Generally, five performance metrics are required for an outstanding X-ray detector: 1,7–12 (1) a high sensitivity for generating sufficiently large electronic signals for image acquisition at a low dose rate; 13–15 (2) a low detection limit for reducing the human body damage in medical CT; 14,16–18 (3) a low dark current noise for enhancing the signal current along with increasing the sensitivity and decreasing the lowest detection limit; 4,7,9,16,19 (4) a stable dark current baseline without drifting for long time work; 13,15 and (5) a high detective quantum efficiency and high modulation transfer function for high-resolution X-ray imaging. 20–22 Therefore, the detection semiconductor materials should possess a high mobility lifetime product ( μτ > 10 −4 cm 2 V −1 ), a high X-ray absorption coefficient, a high resistivity (about 10 9 –10 12 Ω cm), and a negligible polarization or ion migration to meet the demands of the detectors.…”