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Metal halide perovskite single crystals are promising for hard X‐ray detection, but growth of large‐sized thin single crystals and inhibition of halide ion migration under high bias are challenging. Herein, the preparation of dense stacking of oriented millimeter‐sized perovskite single crystals with capability of large‐area fabrication, controlled thickness, and high ion migration activation energy (Ea)is reported. The oriented growth results in absence of grain boundaries parallel with the substrates, leading to large carrier mobility‐lifetime (µτ) product of 2.7 × 10−3 cm2 V−1, which is comparable to values of many perovskite bulk single crystals. Under low bias, hard X‐ray detectors exhibit high sensitivity of 1.2 × 104 µC Gy−1 cm−2 and low detection limit of 87.5 nGy s−1, which are comparable to those of many single‐crystal hard X‐ray detectors under high bias. Moreover, combination of low bias and high Ea results in weak halide ion migration and small dark current drift of 3.2 × 10−4 nA cm−1 s−1 v−1. Benefited from the superior detector performance, high‐contrast hard X‐ray imaging can be obtained at a low dose rate of 1.26 µGy s−1. The work may promote the application of perovskite hard X‐ray detectors in practical imaging area. [ABSTRACT FROM AUTHOR]

MOFs have good potential for X-ray detection, but direct X-ray detection in single crystal form is rarely reported. In this work, we successfully synthesized Pb-TCPE, and the single crystal achieves a low detection limit and high detection sensitivity of 4812.6 μC Gyair−1 cm−2, which exhibits great potential for X-ray detection and imaging. [ABSTRACT FROM AUTHOR]

Inorganic Bi‐based perovskites have shown great potential in X‐ray detection for their large absorption to X‐rays, diverse low‐dimensional structures, and eco‐friendliness without toxic metals. However, they suffer from poor carrier transport properties compared to Pb‐based perovskites. Here, we propose a mixed‐halogen strategy to tune the structural dimensions and optoelectronic properties of Cs3Bi2I9−nBrn (0≤n≤9). Ten centimeter‐sized single crystals are successfully grown by the Bridgman technique. Upon doping bromine to zero‐dimensional Cs3Bi2I9, the crystal transforms into a two‐dimensional structure as the bromine content reaches Cs3Bi2I8Br. Correspondingly, the optoelectronic properties are adjusted. Among these crystals, Cs3Bi2I8Br exhibits negligible ion migration, moderate resistivity, and the best carrier transport capability. The sensitivities in 100 keV hard X‐ray detection are 1.33×104 and 1.74×104 μC Gyair−1 cm−2 at room temperature and 75 °C, respectively, which are the highest among all reported bismuth perovskites. Moreover, the lowest detection limit of 28.6 nGyair s−1 and ultralow dark current drift of 9.12×10−9 nA cm−1 s−1 V−1 are obtained owing to the high ionic activation energy. Our work demonstrates that Br incorporation is an effective strategy to enhance the X‐ray detection performance by tuning the dimensional and optoelectronic properties. [ABSTRACT FROM AUTHOR]

Inorganic Bi‐based perovskites have shown great potential in X‐ray detection for their large absorption to X‐rays, diverse low‐dimensional structures, and eco‐friendliness without toxic metals. However, they suffer from poor carrier transport properties compared to Pb‐based perovskites. Here, we propose a mixed‐halogen strategy to tune the structural dimensions and optoelectronic properties of Cs3Bi2I9−nBrn (0≤n≤9). Ten centimeter‐sized single crystals are successfully grown by the Bridgman technique. Upon doping bromine to zero‐dimensional Cs3Bi2I9, the crystal transforms into a two‐dimensional structure as the bromine content reaches Cs3Bi2I8Br. Correspondingly, the optoelectronic properties are adjusted. Among these crystals, Cs3Bi2I8Br exhibits negligible ion migration, moderate resistivity, and the best carrier transport capability. The sensitivities in 100 keV hard X‐ray detection are 1.33×104 and 1.74×104 μC Gyair−1 cm−2 at room temperature and 75 °C, respectively, which are the highest among all reported bismuth perovskites. Moreover, the lowest detection limit of 28.6 nGyair s−1 and ultralow dark current drift of 9.12×10−9 nA cm−1 s−1 V−1 are obtained owing to the high ionic activation energy. Our work demonstrates that Br incorporation is an effective strategy to enhance the X‐ray detection performance by tuning the dimensional and optoelectronic properties. [ABSTRACT FROM AUTHOR]

Scintillators, which can convert high‐energy ionizing radiation (e.g., X‐ or γ‐rays) into ultraviolet‐visible light, have been widely applied in medical and industrial fields. Developing new scintillation materials with high performance and low cost is very desirable in order to address the growing application demands. Among them, single‐crystal scintillators of organic‐inorganic hybrid metal halides (OIMHs) have attracted much attention because of their excellent optical transparency, suppressed light scattering, and facile solution preparation methods. Herein, three new centimeter‐sized (2‐DMAP)2MnX4 (2‐DMAP+ = 2‐dimethylaminopyridinium, X = Cl, Br, I) single crystals with high crystal quality are synthesized via the solvent evaporation method. Benefiting from the high optical transparency and remarkable luminescence property, (2‐DMAP)2MnBr4 delivers a high X‐ray light yield of 22 000 photons MeV−1, a low limit of detection of 9.50 nGy s−1, and an excellent X‐ray imaging spatial resolution of 20–25 lp mm−1. Moreover, the regulation of single‐crystal thickness from 0.31 mm to 3.03 mm can be easily achieved via a simple solution post‐treatment method, which has a significant influence on the transmittance, spatial imaging resolution, and detection limit. This work demonstrates a promising single‐crystal scintillator for the application of high‐resolution X‐ray imaging with low preparation cost and tunable thickness. [ABSTRACT FROM AUTHOR]

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 [1¯01]$[{\bar{1}}01]$ crystal orientations. Based on anisotropic responses of material properties and detection performances, it is found that the [1¯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. [ABSTRACT FROM AUTHOR]

Perovskite single crystals and polycrystalline films have complementary merits and deficiencies in X‐ray detection and imaging. Herein, we report preparation of dense and smooth perovskite microcrystalline films with both merits of single crystals and polycrystalline films through polycrystal‐induced growth and hot‐pressing treatment (HPT). Utilizing polycrystalline films as seeds, multi‐inch‐sized microcrystalline films can be in situ grown on diverse substrates with maximum grain size reaching 100 μm, which endows the microcrystalline films with comparable carrier mobility‐lifetime (μτ) product as single crystals. As a result, self‐powered X‐ray detectors with impressive sensitivity of 6.1×104 μC Gyair−1 cm−2 and low detection limit of 1.5 nGyair s−1 are achieved, leading to high‐contrast X‐ray imaging at an ultra‐low dose rate of 67 nGyair s−1. Combining with the fast response speed (186 μs), this work may contribute to the development of perovskite‐based low‐dose X‐ray imaging. [ABSTRACT FROM AUTHOR]

Perovskite single crystals and polycrystalline films have complementary merits and deficiencies in X‐ray detection and imaging. Herein, we report preparation of dense and smooth perovskite microcrystalline films with both merits of single crystals and polycrystalline films through polycrystal‐induced growth and hot‐pressing treatment (HPT). Utilizing polycrystalline films as seeds, multi‐inch‐sized microcrystalline films can be in situ grown on diverse substrates with maximum grain size reaching 100 μm, which endows the microcrystalline films with comparable carrier mobility‐lifetime (μτ) product as single crystals. As a result, self‐powered X‐ray detectors with impressive sensitivity of 6.1×104 μC Gyair−1 cm−2 and low detection limit of 1.5 nGyair s−1 are achieved, leading to high‐contrast X‐ray imaging at an ultra‐low dose rate of 67 nGyair s−1. Combining with the fast response speed (186 μs), this work may contribute to the development of perovskite‐based low‐dose X‐ray imaging. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid copper(I)‐based halides have attracted great interest in the field of optoelectronics due to their low cost, non‐toxicity, large Stokes shift, and high photoluminescence quantum yields (PLQYs). Here, bulk zero‐dimensional (0D) organic‐inorganic hybrid copper(I)‐based (R,S‐2‐mpip)2Cu2I6 (mpip = methylpiperazinium, C5H14N22+) single crystals have been grown with equal stoichiometric ratios of R‐ and S‐2‐mpip ligands by chirality–racemization strategy for the first time. Interestingly, (R,S‐2‐mpip)2Cu2I6 single crystals exhibit strong blue–green photoluminescence (PL) located at 520 nm with large Stokes shift of about 230 nm and high PLQY of about 65.96%, which originates from self‐trapped excitons (STEs). More importantly, (R,S‐2‐mpip)2Cu2I6 single crystals also exhibit the strong radioluminescence (RL) at 520 nm, the fast X‐ray scintillation response with a light yield of about 47 000 photon MeV−1 and low detection limit of 6.48 nGyairs−1 when exposed to X‐ray irradiation condition, which is superior to that of other copper(I) iodide‐based hybrids. Based on the excellent characteristics, X‐ray imaging systems based on (R,S‐2‐mpip)2Cu2I6 single crystals exhibit the clear images of "QFNU" logo and crystal symbol pattern. This work not only deepens the understandings of material design and fundamental properties of these racemate systems, but also provides guidance for the further applications in the multi‐functional optoelectronics. [ABSTRACT FROM AUTHOR]

Semiconductor heterostructures underpin the design and performance of virtually all modern optoelectronic systems. The clear interface, high crystalline quality, and suitable energy band match lay the foundation for high‐performance heterojunction optoelectronic devices. Here, a facile solution epitaxial growth method is demonstrated for controllably growing CH3NH3PbBr3 single crystal (SC) on the CH3NH3PbCl3 SC, which forms a pn heterojunction with a well‐defined interface and high single‐crystalline quality. The thickness of the epitaxial layer can be finely controlled by adjusting the growth time. Benefiting from excellent built‐in electrical potential at pn heterojunction, the heterojunction detector shows an obvious rectification behavior and high performance in photo‐imaging and X‐ray detection without any power supply, including high responsivity (26.8 mA W−1), fast response time (8/613 µs), and high sensitivity of 868 µC Gyair−1 cm−2 with a record lowest detectable X‐ray dose rate of 15.5 nGyair s−1. Furthermore, it exhibits high‐fidelity UV photo‐imaging capability at zero bias voltage. In addition, the heterojunction detector shows excellent stability by maintaining 99% of the initial responsivity after 120 days without any encapsulation in the atmosphere. This work enables a significant advance in engineering perovskite SC heterojunction for developing novel and functional devices. [ABSTRACT FROM AUTHOR]

Lead-based organic–inorganic hybrid perovskite single crystals (OIHP SCs) offer promising opportunity for X-ray detection and imaging owing to their high X-ray attenuation coefficient, excellent optoelectronic properties, and simple fabrication processes. Nevertheless, it remains a key challenge to reduce its dark current and meanwhile maintain a high sensitivity. Herein, we developed an on-substrate method for growing methylamine lead bromide (MAPbBr3) SCs on aluminum oxide (Al2O3) layer coated indium tin oxide (ITO) glass. The photodiode based on this approach exhibits an ultralow-dark-current density of 1 nA cm−2 at an operative voltage of −5 V, a signal-to-noise ratio (SNR) more than 80 dB, and meanwhile retaining a high X-ray sensitivity of 2.02 $\times 10^{{3}}\,\, \mu \text{C}\cdot $ ${\mathrm {Gy}}_{\text {air}}^{-1} \cdot $ cm−2. Our further investigation reveals that the dark current was reduced due to two beneficial effects of the Al2O3 layer in tandem, including the interfacial defect passivation and blocking of hole injection by increased interfacial energy barrier. Our approach sheds light on advancing the fabrication of high-performance OIHP SCs-based X-ray sensors that can be potentially integrated with large-area readout panel at low temperature. [ABSTRACT FROM AUTHOR]

Low‐dimensional perovskite halides have shown a great potential as X‐ray detection materials because of efficient exciton emissions originating from strongly spatially localized charge carriers. Nonetheless, most of them have a scintillation yield far below their theoretical limits. Here, it is found that the harvesting efficiency of produced charge carriers can be significantly enhanced via a small amount of In+ doping in these highly localized structures. A bright and sensitive zero‐dimensional Cs3Cu2I5:In+ halide with efficient and tunable dual emission is reported. The radioluminescence emission of Cs3Cu2I5:In+ crystals under X‐ray excitation consists of a self‐trapped exciton emission at 460 nm and an In+‐related emission at 620 nm at room temperature. In+ doping enhances the photoluminescence quantum efficiency (PLQY) of Cs3Cu2I5 from 68.1% to 88.4%. Benefiting from the higher PLQY, Cs3Cu2I5:In+ can achieve an excellent X‐ray detection limit of 96.2 nGyair s−1, and a superior scintillation yield of 53 000 photons per MeV, which is comparable to commercial CsI:Tl single crystals. As a result, a remarkable X‐ray imaging resolution of 18 line pairs mm–1 is demonstrated, which is so far a record resolution for single crystal perovskite‐based flat‐panel detectors. These results highlight the importance of efficient harvesting of carriers (and excitons) in low‐dimensional perovskites for radiation detection applications. [ABSTRACT FROM AUTHOR]

X-ray detection plays an extremely significant function in medical diagnosis, nondestructive testing, safety testing, scientific research, environmental monitoring and other practical applications. However, conventional inorganic semiconductors, such as amorphous selenium, crystalline Si and pure Ge present almost uncontrollable bandgaps and require quite sophisticated fabrication techniques despite their outstanding performance. As developing materials for direct conversion X-ray detection, halide perovskite semiconductors exhibit remarkable properties with high sensitivity. In this review, we summarize the optoelectronic performance of different dimensional perovskites in X-ray detection and their application in X-ray imaging for perovskite-based X-ray detectors including single crystals, films and wafers. This review aims to preliminarily highlight the relationship between structural dimensionality and X-ray detection properties, which should provide valuable suggestions for researchers to rationally design high-performance halide perovskite X-ray photodetectors through crystal engineering at the molecular level in the future. [ABSTRACT FROM AUTHOR]

Lone-pair Electrons Enhancement Effect: SnTe3O8 Hard X-ray Detection with Stable High-temperature Sensitivity and Ultralow Detection Limit (Adv. Funct. Keywords: 120 keV hard X-ray detections; high-temperature sensitivity; lone-pair electrons enhancement effects; tellurite oxide single crystals; ultralow detection limits; X-ray imaging EN 120 keV hard X-ray detections high-temperature sensitivity lone-pair electrons enhancement effects tellurite oxide single crystals ultralow detection limits X-ray imaging 1 1 1 07/06/23 20230704 NES 230704 B X-Ray Imaging b In article 2301002, Xutang Tao, Zeliang Gao, and co-workers report a novel high-temperature X-ray detection crystal of SnTe SB 3 sb O SB 8 sb . 120 keV hard X-ray detections, high-temperature sensitivity, lone-pair electrons enhancement effects, tellurite oxide single crystals, ultralow detection limits, X-ray imaging. [Extracted from the article]