Wide‐Bandgap Rare‐Earth Iodate Single Crystals for Superior X‐Ray Detection and Imaging

Abstract

Semiconductor‐based X‐ray detectors with low detectable thresholds become critical in medical radiography applications. However, their performance is generally limited by intrinsic defects or unresolved issues of materials, and developing a novel scintillation semiconductor for low‐dose X‐ray detection is a highly urgent objective. Herein, a high‐quality rare‐earth iodate Tm(IO3)3 single crystal grown through low‐cost solution processing is reported with a wide bandgap of 4.1 eV and a large atomic number of 53.2. The roles of IO and TmO groups for charge transport in the Tm(IO3)3 are revealed with the structural difference between the [101] and false[true1¯01false]$[{\bar{1}}01]$ crystal orientations. Based on anisotropic responses of material properties and detection performances, it is found that the [true1¯01${\bar{1}}01$] orientation, the path with fewer IO groups, achieves a high resistivity of 1.02 × 1011 Ω cm. Consequently, a single‐crystal detector exhibits a low dark current and small baseline drifting due to the wide bandgap, high resistivity and less ion migration of Tm(IO3)3, resulting in a low detection limit of 85.2 nGyair s−1. An excellent X‐ray imaging performance with a high sensitivity of 4406.6 µC Gyair−1 cm−2 is also shown in the Tm(IO3)3 device. These findings provide a new material design perspective for high‐performance X‐ray imaging applications.

Flexible strontium-based metal–organic framework scintillation screens for high-resolution X-ray imaging

“…The limit of detection (LOD) of scintillators defined as the dose rate when the signal to noise ratio (SNR) ≥ 3. 22 The LOD of 1 is 4.96 μGy s −1 (Fig. 2d), which is slightly lower than the requirement for medical diagnosis (5.50 μGy s −1 ).…”

Efficient X-ray Detection of Polyoxometalates@Metal–Organic Frameworks Based on Host–Guest Electron Transfer

“…The high E a and E g values of 1 and 2 suppress the heat and visible-light interference, facilitating the provision of high stability and low noise. 2,3,6 The I−t curves were measured by cycling the switched X-ray at different bias voltages (Figure S14), which suggests that the photogenerated carriers are efficiently generated and transported under an X-ray. Detectors 1 and 2 could generate stable photocurrent gains at 100 V, indicating high electric-field stability (Figure S15).…”

“…The solid-state ultraviolet–visible (UV-vis) absorption spectra of 1 and 2 were measured at room temperature (Figure S12) and the bandgaps ( E g ) were fitted by the Kubelka–Munk function to be 2.60 and 3.23 eV, respectively (Figure S13). The high E a and E g values of 1 and 2 suppress the heat and visible-light interference, facilitating the provision of high stability and low noise. ,, …”

“…2 An efficient direct-type Xray detector should be characterized by strong X-ray absorption, low dark current, large charge carrier mobility and lifetime product (μτ), and high detection sensitivity (S), as well as a low limit of detection. 3 Although diverse semiconductors have been utilized for direct-type X-ray detection, many constraints remain limiting their broader applications. 4 The α-Se and Si wafers have been broadly commercialized, but the relatively poor X-ray absorption can hardly satisfy high-energy X-ray detection.…”

The Structure Determination of Organic Molecules by Co-crystallization of Anthracene-Based Crystallization Chaperone

“…Whether the organic compounds are natural products − or synthesized by chemists, it is extremely important to determine their structures and absolute conformations at the atomic level. Over the past few decades, numerous researchers have developed and refined many methods for the structural identification of organic molecules, such as nuclear magnetic resonance ( NMR ), − infrared spectroscopy ( IR ), − mass spectrometry ( MS ), − single crystal X-ray diffraction ( X-ray SCD ), − etc. Among them, X-ray SCD can provide direct and accurate structural information and is globally recognized as a fairly reliable method for the structural identification of organic compounds, including their stereochemical conformation.…”