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Halide perovskites (HPs) recently have emerged as one class of competitive scintillators for X‐ray detection and imaging owing to its high quantum efficiency, short decay time, superior X‐ray absorption capacity, low cost, and ease of crystal growth. The tunable structure and versatile chemical compositions of halide perovskites provide distinguishable advantages over traditional inorganic scintillators for optimizing scintillation performance. Since the first observation of the scintillation phenomenon in HPs, substantial efforts have been devoted to expanding the inventory of HP scintillators and regulating material properties. Understanding the relationship between the structure and scintillation properties of HP scintillators is essential for developing materials with improved X‐ray detection and imaging capacities. This review summarizes strategies for improving the light yield of HP scintillators and provides a roadmap for improving the X‐ray imaging performance. Additionally, methods for controlling the light propagation direction in HP scintillators are highlighted for improving X‐ray imaging resolution. Finally, we highlight the current challenge in HP scintillators and provide a perspective on the future development of this emerging scintillator. [ABSTRACT FROM AUTHOR]

The development of high‐performance X‐ray detectors requires scintillators with fast decay time, high light yield, stability, and X‐ray absorption capacity, which are difficult to achieve in a single material. Here, we present the first example of a lanthanide chalcogenide of LaCsSiS4 : 1 % Ce3+ that simultaneously integrates multiple desirable properties for an ideal scintillator. LaCsSiS4 : 1 % Ce3+ demonstrates a remarkably low detection limit of 43.13 nGyair s−1 and a high photoluminescence quantum yield of 98.24 %, resulting in a high light yield of 50480±1441 photons/MeV. Notably, LaCsSiS4 : 1 % Ce3+ exhibits a fast decay time of only 29.35±0.16 ns, making it one of the fastest scintillators among all lanthanide‐based inorganic scintillators. Furthermore, this material shows robust radiation and moisture resistance, endowing it with suitability for chemical processing under solution conditions. To demonstrate the X‐ray imaging capacity of LaCsSiS4 : 1 % Ce3+, we fabricated a flexible X‐ray detector that achieved a high spatial resolution of 8.2 lp mm−1. This work highlights the potential of lanthanide chalcogenide as a promising candidate for high‐performance scintillators. [ABSTRACT FROM AUTHOR]

Periodically arranging coordination‐distinct actinides into one crystalline architecture is intriguing but of great synthetic challenge. We report a rare example of a heterobimetallic actinide metal–organic framework (An‐MOF) by a unique reaction‐induced preorganization strategy. A thorium MOF (SCU‐16) with the largest unit cell among all Th‐MOFs was prepared as the precursor, then the uranyl was precisely embedded into the MOF precursor under oxidation condition. Single crystal of the resulting thorium‐uranium MOF (SCU‐16‐U) shows that a uranyl‐specific site was in situ induced by the formate‐to‐carbonate oxidation reaction. The heterobimetallic SCU‐16‐U exhibits multifunction catalysis properties derived from two distinct actinides. The strategy proposed here offers a new avenue to create mixed‐actinide functional material with unique architecture and versatile functionality. [ABSTRACT FROM AUTHOR]

Although examples of multiple bonds between actinide elements and main‐group elements are quite common, studies of the multiple bonds between actinide elements and transition metals are extremely rare owing to difficulties associated with their synthesis. Here we report the first example of molecular uranium complexes featuring a cis‐[M→→ ${{\rm{ \mathbin{{\stackrel{\textstyle\rightarrow} { {\smash{\rightarrow}\vphantom{_{\vbox to.5ex{\vss}}}} } }} }}}$ U←← ${{\rm{ \mathbin{{\stackrel{\textstyle\leftarrow} { {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}} } }} }}}$ M] core (M=Rh, Ir), which exhibits an unprecedented arrangement of two M→→ ${{\rm{ \mathbin{{\stackrel{\textstyle\rightarrow} { {\smash{\rightarrow}\vphantom{_{\vbox to.5ex{\vss}}}} } }} }}}$ U double dative bond linkages to a single U center. These complexes were prepared by the reactions of chlorine‐bridged heterometallic complexes [{U{N(CH3)(CH2CH2NPiPr2)2}(Cl)2[(μ‐Cl)M(COD)]2}] (M=Rh, Ir) with MeMgBr or MeLi, a new method for the construction of species with U−M multiple bonds. Theoretical calculations including dispersion confirmed the presence of two U←← ${{\rm{ \mathbin{{\stackrel{\textstyle\leftarrow} { {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}} } }} }}}$ M double dative bonds in these complexes. This study not only enriches the U←← ${{\rm{ \mathbin{{\stackrel{\textstyle\leftarrow} { {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}} } }} }}}$ M multiple bond chemistry, but also provides a new opportunity to explore the bonding of actinide elements. [ABSTRACT FROM AUTHOR]

Metal organic frameworks (MOFs) are a distinct family of crystalline porous materials finding extensive applications. Their synthesis often requires elevated temperature and relatively long reaction time. We report here the first case of MOF synthesis activated by high‐energy (1.5 MeV) electron beam radiation from a commercially available electron‐accelerator. Using ZIF‐8 as a representative for demonstration, this type of synthesis can be accomplished under ambient conditions within minutes, leading to energy consumption about two orders of magnitude lower than that of the solvothermal condition. Interestingly, by controlling the absorbed dose in the synthesis, the electron beam not only activates the formation reaction of ZIF‐8, but also partially etches the material during the synthesis affording a hierarchical pore architecture and highly crystalline ZnO nanoparticles on the surface of ZIF‐8. This gives rise to a new strategy to obtain MOF@metal oxide heterostructures, finding utilities in photocatalytic degradation of organic dyes. [ABSTRACT FROM AUTHOR]

Scintillators display radioluminescent properties when irradiated by high‐energy photons and therefore play an essential role in radiation detection. The current inventory of scintillators is overwhelmingly represented by achiral structures, where the radioluminescence propagates isotropically after generation. Herein, we demonstrate that chiral perovskites of (R‐3AP)PbBr3Cl⋅H2O (R‐3APP) and (S‐3AP)PbBr3Cl⋅H2O (S‐3APP) emerge as a new type of scintillator displaying a distinct property of circularly polarized radioluminescence (CPRL). A high quantum yield of 27.6 %, high luminescence dissymmetric factors (glum) of 4×10−2, and high X‐ray absorption coefficients were observed for these compounds. As proof of concept, we fabricated a polarized scintillator pair by assembling chiral scintillator crystals, which provides a new strategy to attenuate optical crosstalk between the scintillators by precisely controlling the radioluminescence propagation and improves the X‐ray imaging quality at the boundary region. [ABSTRACT FROM AUTHOR]

Luminescent covalent organic frameworks (COFs) find promising applications in chemical sensing, photocatalysis, and optoelectronic devices, however, the majority of COFs are non or weakly emissive owing to the aggregation‐caused quenching (ACQ) or the molecular thermal motion‐based energy dissipation. Here, we report a previously unperceived approach to improve luminescence performance of COFs by introducing isotope effect, which is achieved through substitution of hydrogen from high‐frequency oscillators X‐H (X=O, N, C) by heavier isotope deuterium. Combining the "bottom‐up" and in situ deuteration methods generates the first deuterated COF, which exhibits an impressively 19‐fold enhancement in quantum yield over that of the non‐deuterated counterpart. These results are interpreted by theoretical calculations as the consequence of slower C/N‐D and OD⋅⋅⋅O vibrations that impede the nonradiative deactivation process. The proposed strategy is proved applicable to many other types of emissive COFs. [ABSTRACT FROM AUTHOR]

Halide hybrid perovskites are attracting considerable attention as highly promising candidates for directly sensing X‐ray radiation, but it is challenging to realize passive X‐ray detection without an external power supply. However, the bulk photovoltaic effect (BPVE) in ferroelectrics promotes the independent separation of photoexcited carriers. Herein, by dimensionality reconstruction of a pure‐two‐dimensional (P‐2D) monolayered perovskite (CH3OC3H9N)2PbBr4, we obtained a quasi‐two‐dimensional (Q‐2D) ferroelectric (CH3OC3H9N)2CsPb2Br7. Converting P‐2D into Q‐2D perovskite stimulates a significant BPVE associated with robust ferroelectricity, as well as an enhanced mobility lifetime product. These features show the potential of the first passive X‐ray detector based on ferroelectrics with an impressive sensitivity up to 410 μC Gy−1 cm−2 at zero bias, which is even superior to the value of the state‐of‐the‐art α‐Se detector operated at relatively high bias. [ABSTRACT FROM AUTHOR]

Zeolites are a well‐known family of microporous aluminosilicate crystals with a wide range of applications. Their industrial synthetic method under hydrothermal condition requires elevated temperature and long crystallization time and is therefore quite energy‐consuming. Herein, we utilize high‐energy electron beam irradiation generated by an industrial accelerator as a distinct type of energy source to activate the formation reaction of Na‐A zeolite. The initial efforts afford an attractive reaction process that can be achieved under ambient conditions and completed within minutes with almost quantitative yield, leading to notable energy saving of one order of magnitude compared to the hydrothermal reaction. More importantly, electron beam irradiation simultaneously exhibits an etching effect during the formation of zeolite generating a series of crystal defects and additional pore windows that can be controlled by irradiation dose. These observations give rise to significantly enhanced surface area and heavy metal removal capabilities in comparison with Na‐A zeolite synthesized hydrothermally. Finally, we show that this method can be applied to many other types of zeolites. [ABSTRACT FROM AUTHOR]

We disclose the intrinsic semiconducting properties of one of the largest mixed‐valent uranium clusters, [H3O+][UV(UVIO2)8(μ3‐O)6(PhCOO)2(Py(CH2O)2)4(DMF)4] (Ph=phenyl, Py=pyridyl, DMF=N,N‐dimethylformamide) (1). Single‐crystal X‐ray crystallography demonstrates that UV center is stabilized within a tetraoxo core surrounded by eight uranyl(VI) pentagonal bipyramidal centers. The oxidation states of uranium are substantiated by spectroscopic data and magnetic susceptibility measurement. Electronic spectroscopy and theory corroborate that UV species serve as electron donors and thus facilitate 1 being a n‐type semiconductor. With the largest effective atomic number among all reported radiation‐detection semiconductor materials, charge transport properties and photoconductivity were investigated under X‐ray excitation for 1: a large on‐off ratio of 500 and considerable charge mobility lifetime product of 2.3×10−4 cm2 V−1, as well as a high detection sensitivity of 23.4 μC Gyair−1 cm−2. [ABSTRACT FROM AUTHOR]

Activation of dinitrogen (N2, 78 %) and dioxygen (O2, 21 %) has fascinated chemists and biochemists for decades. The industrial conversion of N2 into ammonia requires extremely high temperatures and pressures. Herein we report the first example of N2 and O2 cleavage by a uranium complex, [N(CH2CH2NPiPr2)3U]2(TMEDA), under ambient conditions without an external reducing agent. The N2 triple bond breaking implies a UIII–PIII six‐electron reduction. The hydrolysis of the N2 reduction product allows the formation of ammonia or nitrogen‐containing organic compounds. The interaction between UIII and PIII in this molecule allows an eight‐electron reduction of two O2 molecules. This study establishes that the combination of uranium and a low‐valent nonmetal is a promising strategy to achieve a full N2 and O2 cleavage under ambient conditions, which may aid the design of new systems for small molecules activation. [ABSTRACT FROM AUTHOR]

A wide range of tunability in the physical parameters of a semiconductor used for X‐ray detection is desirable to achieve targeted performance optimization. However, in a dense‐phase semiconductor, fine‐tuning one parameter often leads to unwanted changes in other parameters. Herein, the intrinsic openness in an open‐framework semiconductor has been confirmed, for the first time, to be a key structural factor that weakens the mutual exclusivity of the adjustable physical parameters owing to a non‐linear control mechanism. The controllable doping of S in a zeolitic In–Se host results in an optimal balance between resistivity, band gap, and carrier mobility, which finally results in an excellent X‐ray detector with a high figure of merit for the mobility–lifetime product (7.12×10−4 cm2 V−1); this value is superior to that of a commercial α‐Se detector. The current strategy of choosing open‐framework semiconductor materials opens a new window for targeting high‐performance X‐ray detection. [ABSTRACT FROM AUTHOR]

Radio‐photoluminescence (RPL) materials display a distinct radiation‐induced permanent luminescence center, and therefore find application in the detection of ionizing radiation. The current inventory of RPL materials, which were discovered by serendipity, has been limited to a small number of metal‐ion‐doped inorganic materials. Here we document the RPL of a metal–organic framework (MOF) for the first time: X‐ray induced free radicals are accumulated on the organic linker and are subsequently stabilized in the conjugated fragment in the structure, while the metal center acts as the X‐ray attenuator. These radicals afford new emission features in both UV‐excited and X‐ray excited luminescence spectra, making it possible to establish linear relationships between the radiation dose and the normalized intensity of the new emission feature. The MOF‐based RPL materials exhibit advantages in terms of the dose detection range, reusability, emission stability, and energy threshold. Based on a comprehensive electronic structure and energy diagram study, the rational design and a substantial expansion of candidate RPL materials can be anticipated. [ABSTRACT FROM AUTHOR]

Semiconductive metal–organic frameworks (MOFs) have emerged in applications such as chemical sensors, electrocatalysts, energy storage materials, and electronic devices. However, examples of semiconductive MOFs within flexible electronics have not been reported. We present flexible X‐ray detectors prepared by thermoplastic dispersal of a semiconductive MOF (SCU‐13) through a commercially available polymer, poly(vinylidene fluoride). The flexible detectors exhibit efficient X‐ray‐to‐electric current conversion with enhanced charge‐carrier mobility and low trap density compared to pelleted devices. A high X‐ray detection sensitivity of 65.86 μCGyair−1 cm−2 was achieved, which outperforms other pelleted devices and commercial flexible X‐ray detectors. We demonstrate that the MOF‐based flexible detectors can be operated at multiple bending angles without a deterioration in detection performance. As a proof‐of‐concept, an X‐ray phase contrast under bending conditions was constructed using a 5×5 pixelated MOF‐based imager. [ABSTRACT FROM AUTHOR]

The design and synthesis of uranium sorbent materials with high uptake efficiency, capacity and selectivity, as well as excellent hydrolytic stability and radiation resistance remains a challenge. Herein, a polyoxometalate (POM)–organic framework material (SCU‐19) with a rare inclined polycatenation structure was designed, synthesized through a solvothermal method, and tested for uranium separation. Under dark conditions, SCU‐19 can efficiently capture uranium through ligand complexation using its exposed oxo atoms and partial chemical reduction from UVI to UIV by the low‐valent Mo atoms in the POM. An additional UVI photocatalytic reduction mechanism can occur under visible light irradiation, leading to a higher uranium removal without saturation and faster sorption kinetics. SCU‐19 is the only uranium sorbent material with three distinct sorption mechanisms, as further demonstrated by X‐ray photoelectron spectroscopy (XPS) and X‐ray absorption near edge structure (XANES) analysis. [ABSTRACT FROM AUTHOR]

Flexible X-Ray Detector, Lanthanide Chalcogenide Scintillator, Luminescence, X-Ray Imaging Keywords: Flexible X-Ray Detector; Lanthanide Chalcogenide Scintillator; Luminescence; X-Ray Imaging EN Flexible X-Ray Detector Lanthanide Chalcogenide Scintillator Luminescence X-Ray Imaging 1 1 1 08/09/23 20230814 NES 230814 B Scintillators b . In their Communication (e202306465), Xing Dai, Shu-Xian Hu, Yaxing Wang et al. report the chalcogenide-based scintillator LaCsSiS SB 4 sb :1%Ce SP 3+ sp showing multiple properties, such as high light yield, fast decay time, low detection limit, and good radiation/moisture resistance. [Extracted from the article]

Abstract: The combination of high atomic number and high oxidation state in UVI materials gives rise to both high X‐ray attenuation efficiency and intense green luminescence originating from ligand‐to‐metal charge transfer. These two features suggest that UVI materials might act as superior X‐ray scintillators, but this postulate has remained substantially untested. Now the first observation of intense X‐ray scintillation in a uranyl–organic framework (SCU‐9) that is observable by the naked eye is reported. Combining the advantage in minimizing the non‐radiative relaxation during the X‐ray excitation process over those of inorganic salts of uranium, SCU‐9 exhibits a very efficient X‐ray to green light luminescence conversion. The luminescence intensity shows an essentially linear correlation with the received X‐ray intensity, and is comparable with that of commercially available CsI:Tl. SCU‐9 possesses an improved X‐ray attenuation efficiency (E>20 keV) as well as enhanced radiation resistance and decreased hygroscopy compared to CsI:Tl. [ABSTRACT FROM AUTHOR]

Abstract: Actinide based metal–organic frameworks (MOFs) are unique not only because compared to the transition‐metal and lanthanide systems they are substantially less explored, but also owing to the uniqueness of actinide ions in bonding and coordination. Now a 3D thorium–organic framework (SCU‐11) contains a series of cages with an effective size of ca. 21×24 Å. Th4+ in SCU‐11 is 10‐coordinate with a bicapped square prism coordination geometry, which has never been documented for any metal cation complexes. The bicapped position is occupied by two coordinated water molecules that can be removed to afford a very unique open Th4+ site, confirmed by X‐ray diffraction, color change, thermogravimetry, and spectroscopy. The degassed phase (SCU‐11‐A) exhibits a Brunauer–Emmett–Teller surface area of 1272 m2 g−1, one of the highest values among reported actinide materials, enabling it to sufficiently retain water vapor, Kr, and Xe with uptake capacities of 234 cm3 g−1, 0.77 mmol g−1, 3.17 mmol g−1, respectively, and a Xe/Kr selectivity of 5.7. [ABSTRACT FROM AUTHOR]

Precise detection of low-dose X- and γ-radiations remains a challenge and is particularly important for studying biological effects under low-dose ionizing radiation, safety control in medical radiation treatment, survey of environmental radiation background, and monitoring cosmic radiations. We report here a photoluminescent uranium organic framework, whose photoluminescence intensity can be accurately correlated with the exposure dose of X- or γ-radiations. This allows for precise and instant detection of ionizing radiations down to the level of 10−4 Gy, representing a significant improvement on the detection limit of approximately two orders of magnitude, compared to other chemical dosimeters reported up to now. The electron paramagnetic resonance analysis suggests that with the exposure to radiations, the carbonyl double bonds break affording oxo-radicals that can be stabilized within the conjugated uranium oxalate-carboxylate sheet. This gives rise to a substantially enhanced equatorial bonding of the uranyl(VI) ions as elucidated by the single-crystal structure of the γ-ray irradiated material, and subsequently leads to a very effective photoluminescence quenching through phonon-assisted relaxation. The quenched sample can be easily recovered by heating, enabling recycled detection for multiple runs. [ABSTRACT FROM AUTHOR]