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Dual-energy imaging represents a versatile and evolving technology with wide-ranging applications in medicine and beyond. Recent technological developments increased the potential for improved diagnostic accuracy and expanded imaging capabilities across various fields. The purpose of this work is to design and develop an energy-integrating multilayer detector, known as a sandwich detector, aimed at single-shot dual-energy imaging tasks such as material discrimination and contrast cancellation. The sandwich detector uses two complementary metal oxide semiconductor advanced pixel sensors of 50 μm pixel size. The top and bottom sensors detect low-energy (LE) and high-energy (HE) photons, with sensors coupled with 250 and 600 μm scintillators, respectively. For better spectral separation between layers without excessively affecting the detected statistic in the bottom layer, the insertion of a 0.25-mm Cu filter between the layers was found to be the optimal choice, from among the tested 0-, 0.25-, and 0.5-mm filter options. The thickness selection for scintillator and intermediate Cu filter was carried out through a dual-energy simulation model. The experiments confirmed the model's reliability in selecting the optimal thicknesses of the intermediate Cu filter, thereby providing reassurance also on the choice of the top scintillator. [ABSTRACT FROM AUTHOR]

We report the photon (PL), electron (CL) and X-ray (XEL) induced luminescence characteristics of high aspect ratio ultra-long (~ 50 µm) ZnO nanorods (NRs) and discuss the potential for fast X-ray detection based on the consistent and efficient visible emission (~ 580 nm) from ZnO NRs. Nanostructured ZnO scintillators were rearranged to form a vertically well-aligned NR design in order to help light absorption and coupling resulting in luminescent and fast scintillation properties. The design of the nanorod array combines the key advantages of a low-cost growth technique together with environmentally friendly and widely available materials. A low temperature hydrothermal method was adopted to grow ZnO NRs in one cycle growth and their structural, optical and X-ray scintillation properties were investigated. The relatively short (~ 10 µm) ZnO NRs emitting in the near-band-edge region were found to be almost insensitive to X-rays. On the other hand, the higher XEL response of long ZnO NRs, which is a key parameter for evaluation of materials to be used as scintillators for high quality X-ray detection and imaging, along with a decay time response in the order of ns confirmed promising scintillation properties for fast and high-resolution X-ray detector applications. [ABSTRACT FROM AUTHOR]

Pb‐free double‐perovskite (DP) scintillators are highly promising candidates for X‐ray imaging because of their superior optoelectronic properties, low toxicity, and high stability. However, practical applications require Pb‐free DP crystals to be ground and mixed with polymers to produce scintillator films. Grinding can compromise film uniformity and optical properties, thereby affecting imaging resolution. In this study, an in situ fabrication strategy is proposed to facilitate the crystalline growth of Pb‐free Cs2AgInxBi1‐xCl6 micron sheets in polymethyl methacrylate in a single step. By adjusting the In3+/Bi3+ ratio, Cs2AgIn0.9Bi0.1Cl6/PMMA composite films (CFs) with excellent scintillation properties are obtained, including a light yield of up to 32000 photons per MeV and an X‐ray detection limit of 87 nGyairs−1. This strategy also enabled the production of large Cs2AgIn0.9Bi0.1Cl6/PMMA CFs, which demonstrated favorable flexibility and stability, fabricating products with advanced eligibility for commercial applications. The CFs exhibited outstanding performances in X‐ray imaging, producing high‐resolution structures and providing a new avenue for the development of Pb‐free DP materials in fields such as medical imaging and safety detection. [ABSTRACT FROM AUTHOR]

The architectural design and fabrication of low‐cost, high‐performance organic scintillators are critical for medical imaging and material/device analysis. However, achieving large‐area and high‐transparency organic scintillators in a low‐cost and easy‐to‐implement method remains a challenge. Herein, a new design strategy for regulating the side chain length of maleimide derivatives is demonstrated to develop organic scintillators for achieving low‐cost, large‐area, and high spatial resolution in X‐ray imaging. The effective intermolecular interactions and relatively twisted molecular structure endow PAM‐M4 molecule with outstanding scintillator properties. More importantly, as demonstrated for the first time, pure organic glassy films with a diameter over 10 cm and high optical transparency can be prepared by the developed melt‐quenched method using PAM‐M4 crystal powder as a raw material. This glassy film exhibits excellent X‐ray imaging ability with a spatial resolution as high as 27.0 lp mm−1 at MTF = 0.20, which is one of the best results among reported organic scintillators. The results of this work not only develop a new design strategy for high‐performance organic scintillators but also demonstrate a reliable approach to fabricating large area screens with superior spatial resolution for medical or industrial X‐ray imaging applications. [ABSTRACT FROM AUTHOR]

Copper halides, a new class of attractive and potential scintillators, have attracted tremendous attention in X‐ray imaging. However, the ambiguity surrounding their exciton properties and the unclear effect of crystal structure on their photophysical performance hinder an in‐depth understanding of their luminescence mechanism and their further application in the X‐ray imaging field. Herein, copper halide scintillators Cs3Cu2X5 (X = I, Br, and Cl) with a 0D crystal structure is prepared, and their photophysical properties and luminescence mechanism are revealed using both theoretical calculation and experimental verification. The small exciton Bohr diameter together with the high exciton binding energy can cause Cs3Cu2X5 to hold strongly confined excitons and lack quantum‐size effects. The 0D Cs3Cu2X5 materials exhibit a structural framework with a soft crystal lattice and Frenkel excitons with strong confinement effects, further resulting in a luminescence mechanism with self‐trapped excitons. In particular, Cs3Cu2I5 is demonstrated as an efficient scintillator with high radioluminescence efficiency and high spatial resolution of ≈106 µm in radiography, which is primarily attributed to strongly confined excitons to improve the radiative recombination probability of electron‐hole pairs. Overall, this work provides a pathway for developing 0D scintillators with strongly confined excitons to improve X‐ray imaging performance. [ABSTRACT FROM AUTHOR]

Due to the rapid advancements in medical radiography, nondestructive inspection, and radiation detection, there is an increasing demand for scintillators that offer both cost-effectiveness and high-resolution X-ray imaging. In this study, we have successfully synthesized transparent glass-ceramic scintillator by embedding Tb3+-doped NaLu 2 F 7 nanocrystals in a glass matrix. This scintillator demonstrates excellent spatial resolution of 20 lp/mm in X-ray imaging due to its high transmittance (over 90% at 550 nm) and intense luminescent intensity when excited by X-ray (151% higher than that of the Bi 4 Ge 3 O 12 scintillator). More significantly, the as-synthesized scintillator exhibits exceptional stabilities at high temperature, moisture levels, and moderate radiation exposure. Notably, any decline in performance caused by long-term exposure to high-dose X-ray can be fully recovered through heat treatment at 350 °C for 30 min. These findings highlight the great potential of NaLu 2 F 7 :Tb3+ glass ceramics as suitable options for high-resolution and retrievable X-ray imaging. [ABSTRACT FROM AUTHOR]

Long‐lasting radioluminescence scintillators have recently attracted substantial attention from both research and industrial communities, primarily due to their distinctive capabilities of converting and storing X‐ray energy. However, determination of energy‐conversion kinetics in these nanocrystals remains unexplored. Here we present a strategy to probe and unveil energy‐funneling kinetics in NaLuF4:Mn2+/Gd3+ nanocrystal sublattices through Gd3+‐driven microenvironment engineering and Mn2+‐mediated radioluminescence profiling. Our photophysical studies reveal effective control of energy‐funneling kinetics and demonstrate the tunability of electron trap depth ranging from 0.66 to 0.96 eV, with the corresponding trap density varying between 2.38×105 and 1.34×107 cm−3. This enables controlled release of captured electrons over durations spanning from seconds to 30 days. It allows tailorable emission wavelength within the range of 520–580 nm and fine‐tuning of thermally‐stimulated temperature between 313–403 K. We further utilize these scintillators to fabricate high‐density, large‐area scintillation screens that exhibit a 6‐fold improvement in X‐ray sensitivity, 22 lp/mm high‐resolution X‐ray imaging, and a 30‐day‐long optical memory. This enables high‐contrast imaging of injured mice through fast thermally‐stimulated radioluminescence readout. These findings offer new insights into the correlation of radioluminescence dynamics with energy‐funneling kinetics, thereby contributing to the advancement of high‐energy nanophotonic applications. [ABSTRACT FROM AUTHOR]

Scintillators with high light yield, spatial resolution, and detection sensitivity are desirable for X‐ray imaging. Howerer, it remains challenging to improve the light yield and radiation detection capability of alkali metal rare‐earth fluoride (ALnF4). Herein, a type of Cu2+ ion heterovalent co‐doped LiLuF4:Tb,Cu microcrystalline scintillation material with high light yield, persistent, and thermostimulated luminescence is obtained by defect engineering. The heterovalent codoping strategy not only increases the radioluminescence (RL) intensity, but also introduces more carrier traps in the material to enhance the long‐afterglow and thermoluminescence intensity of LiLuF4:Tb microcrystals. After doping of 3 mol% Cu2+ ions, the RL efficiency is increased by 88.61%, and the X‐ray detection limit of LiLuF4:Tb,Cu reaches 2.7928 nGy·s‒1. This detectivity is considerably lower than the medical imaging requirements (5.5 µGy·s‒1). Furthermore, a large‐area flexible scintillation film of dimensions 30 × 30 cm2 is prepared to achieve high spatial resolution X‐ray imaging of 22 LP mm−1@MTF(modulation transfer function) = 0.2. Besides, this flexible film enables X‐ray imaging of curved objects and stores optical information for >48 h. This work provides a paradigm for improving the RL intensity and X‐ray detection sensitivity of alkali rare‐earth fluorides by crystal defect engineering, and enriches X‐ray high resolution extended imaging applications. [ABSTRACT FROM AUTHOR]

A series of lead-free Rb2ZrCl6:xTe4+ (x = 0%, 0.1%, 0.5%, 1.0%, 2.0%, 3.0%, 5.0%, 10.0%) perovskite materials were synthesized through a hydrothermal method in this work. The substitution of Te4+ for Zr in Rb2ZrCl6 was investigated to examine the effect of Te4+ doping on the spectral properties of Rb2ZrCl6 and its potential applications. The incorporation of Te4+ induced yellow emission of triplet self-trapped emission (STE). Different luminescence wavelengths were regulated by Te4+ concentration and excitation wavelength, and under a low concentration of Te4+ doping (x ≤ 0.1%), different types of host STE emission and Te4+ triplet state emission could be achieved through various excitation energies. These luminescent properties made it suitable for applications in information encryption. When Te4+ was doped at high concentrations (x ≥ 1%), yellow triplet state emission of Te4+ predominated, resulting in intense yellow emission, which stemmed from strong exciton binding energy and intense electron-phonon coupling. In addition, a Rb2ZrCl6:2%Te4+@RTV scintillating film was fabricated and a spatial resolution of 3.7 lp/mm was achieved, demonstrating the potential applications of Rb2ZrCl6:xTe4+ in nondestructive detection and bioimaging. [ABSTRACT FROM AUTHOR]

Organic scintillators have recently gained considerable attentions in X‐ray detection for their potential applications in biomedical radiograph and security inspection. However, the weak X‐ray absorption and/or inefficient exciton utilization have limited the development and commercialization of organic scintillators. Currently, high‐performance X‐ray organic scintillators are scarce and organic scintillators with dual triplet‐harvesting channels have not been explored before. Here, we develop several proof‐of‐concept sulfone‐based organic molecules, C1–C7, using different alkoxy chains to manipulate molecular packing mode. These materials exhibit dual triplet‐harvesting channels of thermally activated delayed fluorescence (TADF) and room‐temperature phosphorescence (RTP) in aggregated state. Inspiringly, these molecules display distinct radioluminescence under the X‐ray stimulation. Among them, C6 behaves the highest light yield of 16,558 photons MeV−1. Moreover, clear X‐ray images are demonstrated in both aggregated state and single‐molecule level. High spatial resolutions of 15.0 and 10.6 line pairs per millimeter (lp mm−1) are achieved for rigid and flexible scintillator screens, exceeding most reported organic and conventional inorganic scintillators. These results highlight the great potential of organic molecules with TADF and RTP nature for efficient X‐ray scintillation and imaging. [ABSTRACT FROM AUTHOR]

X-ray detectors based on scintillators are widely used in the fields of medical imaging, high-energy physics, geological exploration, and industrial detection. The development of scintillation materials with different characteristics has become the focus of considerable research interest. Herein, we report a facile hydrothermal synthesis of Gd- and Eu-codoped LiLuF4 microcrystals (MCs), which exhibit strong luminescence of Eu3+ ion characteristic emission, characterized by distinct red fluorescence emission. The research shows that Gd3+ co-doping effectively improved the sensitivity and light yield of LiLuF4:Eu MCs by regulating the proportion of co-doping ions. In addition, the detection limit is 140.72 nGy s−1 for LiLuF4:Eu,Gd MCs, approximately 39 times lower than the dose requirement of medical diagnosis. Based on LiLuF4:Eu,Gd MCs with the superior scintillation properties, a MC-composited film with 250 μm thickness was prepared by a direct coating method. The uniform and high-loading scintillation film exhibits outstanding imaging performance with a high spatial resolution of 14.8 LP mm−1, which confirms the application potential of X-ray imaging. [ABSTRACT FROM AUTHOR]

The thickness of the scintillation films in indirect X−ray detectors can significantly influence their luminescence intensity. However, due to the scattering and attenuation of incoherent photons, thick scintillation films tend to reduce light yield. Herein, a highly transparent perovskite glass−ceramic scintillation film, in which the CsPbBr3 nanocrystals are in-situ grown inside a transparent amorphous polymer structure, is designed to achieve ultrastable and efficient X-ray imaging. The crystal coordination−topology growth and in−situ film formation strategy is proposed to control the crystal growth and film thickness, which can prevent light scattering and non−uniform distribution of CsPbBr3 nanocrystals while providing sufficient film thickness to absorb X−ray, thus enabling a high−quality glass−ceramic scintillator without agglomeration and Ostwald ripening. This glass−ceramic scintillation film with a thickness of 250 μm achieves a low detection limit of 326 nGyair s−1 and a high spatial resolution of 13.9 lp mm−1. More importantly, it displays remarkable scintillation stability under X−ray irradiation (radiation intensity can still reach 95% at 278 μGyair s−1 for 3600 s), water soaking (150 days), and high−temperature storage (150 days at 60 °C). Hence, this work presents a approach to construct ultrastable and flexible scintillation films for X−ray imaging with reduced light scattering and improved resolution. [ABSTRACT FROM AUTHOR]

In recent years, the development of new scintillation materials with red and near-infrared light emission has had significant advantages based on the development of an avalanche photodiode with high quantum yield. This study used a hydrothermal method to synthesize rare-earth-doped Cs2NaScCl6 crystals, in which a red emission of Cs2NaScCl6:Sm was investigated with high X-ray sensitivity and low detection limit. In addition, a tunable wavelength range of radioluminescence can be achieved, in which a near-white light emission can be generated by precisely controlling the proportion of Sm3+ and Tb3+ doping concentrations. Meanwhile, a Cs2NaScCl6:7%Sm scintillation film has been successfully prepared by direct coating with a thickness of 150 μm, which achieves a spatial resolution of 11.9 lp mm−1 based on X-ray imaging experiments. Therefore, this perovskite material has shown potential application as an eco-friendly multifunctional imaging material. [ABSTRACT FROM AUTHOR]

Thermally activated delayed fluorescence (TADF) emitters featuring through‐space charge transfer (TSCT) can be excellent candidates for piezochromic luminescent (PCL) materials due to their structural dynamics. Spatial donor‐acceptor (D−A) stacking arrangements enable the modulation of inter‐ and intramolecular D−A interactions, as well as spatial charge transfer states, under varying pressure conditions. Herein, we demonstrate an effective approach toward dynamic reversible full‐color PCL materials with TSCT‐TADF characteristics. Their single crystals exhibit a full‐color‐gamut PCL process spanning a range of 170 nm. Moreover, the TSCT‐TADF‐PCL emitters display a unity photoluminescence quantum yield, and show promising application in X‐ray scintillator imaging. [ABSTRACT FROM AUTHOR]

Organic scintillators have recently attracted growing attention for X‐ray detection in industrial and medical applications. However, these materials still face critical obstacles of low attenuation efficiency and/or inefficient triplet exciton utilization. Here we developed a new category of organogold(III) complexes, Tp‐Au‐1 and Tp‐Au‐2, through adopting a through‐space interaction motif to realize high X‐ray attenuation efficiency and efficient harvesting of triplet excitons for emission. Thanks to the efficient through‐space charge transfer process, this panel of complexes achieved higher photoluminescence quantum yield and shorter radiative lifetimes compared with the through‐bond reference complexes. Inspiringly, these organogold(III) complexes exhibited polarity‐dependent emission origins: thermally activated delayed fluorescence and/or phosphorescence. Under X‐ray irradiation, Tp‐Au‐2 manifested intense radioluminescence together with a record‐high scintillation light yield of 77,600 photons MeV−1 for organic scintillators. The resulting scintillator screens demonstrated high‐quality X‐ray imaging with >16.0 line pairs mm−1 spatial resolution, outstripping most organic and inorganic scintillators. This finding provides a feasible strategy for the design of superior organic X‐ray scintillators. [ABSTRACT FROM AUTHOR]

Quasi-zero-dimensional quantum dots (QDs) have garnered significant attention owing to their distinct structural attributes, quantum confinement behaviors, optoelectronic characteristics, etc. Regrettably, their susceptibility to stability poses a challenge. In this context, leveraging rational component regulation and crystallization process optimization strategies, we presented the successful preparation of CdS QDs silicate glass through the amalgamation of melt-quenching and controlled crystallization. The optical and morphological analysis substantiated the accomplishment of in-situ precipitation of CdS QDs within the glass matrix, with grain sizes <20 nm. Integrating CdS QDs into an inorganic glass matrix remarkably augmented its fluorescence thermal stability, enabling the preservation of 85.1 % of the room-temperature luminescent intensity even at an elevated temperature of 150 °C. Moreover, the encapsulated W-LED device by near-UV LED chip, CdS QDs glass, and BaMgAl 10 O 17 :Eu2+ phosphor exhibited a warm white-light emission characterized by suitable chromaticity coordinates (0.3741, 0.3452) and a notably high color rendering index (CRI = 93). Ultimately, the radioluminescence behavior of CdS QDs glass was unveiled by utilizing it as the scintillator wafer in an X-ray imaging system, which clearly demonstrated the structure of spring encapsulated within an opaque capsule. In a nutshell, these demonstrations unequivocally emphasize the substantial potential merits of CdS QDs glass, particularly in the domains of long-term W-LED lighting and X-ray imaging applications. [ABSTRACT FROM AUTHOR]

Lead‐free metal halide double perovskites have emerged as promising scintillators owing to their superior optoelectronic properties, low‐cost and solution processability. However, it is still challenging to develop high‐performance flexible X‐ray scintillators based on the B(I)‐site alkali metal modulation in lead‐free double perovskite nanocrystals (NCs). Herein, a series of novel Cs2B(I)GdCl6 (B: Li, Na, K) of double perovskite A2B(I)M(III)X6 NCs structures are successfully synthesized, the optical and scintillator properties of which are significantly sensitive to the B(I)‐site alkali metals with the doping of Sb3+. They showed efficient self‐trapped exciton (STE) emission with high photoluminescence quantum yield (PLQY) and exhibited the highest X‐ray detection limit (86 nGyair s−1) and excellent spatial resolutions (>15 lp mm−1). The femtosecond transient absorption measurement and theoretical analysis further revealed that the B(I)‐site alkali metal fundamentally balanced the exciton–phonon coupling with appropriate STEs formation energy barrier and the electron localization and thus improved the optical and scintillator properties. This B(I)‐site alkali metal engineering offers a strategy to develop bright luminescent double perovskite NCs for X‐ray detection and imaging devices. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid metal halides are widely used in X‐ray detection and imaging due to their high X‐ray absorption efficiency, ease of synthesis, and efficient luminescence. However, the issue of lead toxicity remains a concern. In this study, non‐toxic, 0D 2,2′‐(Ethylenedioxy)bis(ethylamine) manganese (II) bromide (EDBEMnBr4) is synthesized using the simple mechanical grinding method and the solution method that exhibits intense green emission at ≈525 nm. Moreover, the change of structure under the influence of temperature and water significantly affects its fluorescence color under UV light. Scintillator materials with and without moisture exposure showed spatial resolutions of 7 and 4 lp mm−1, and low detection limits of 4.62 and 5.25 µGyair s−1, respectively, meeting medical industry standards (<5.5 µGyair s−1). Furthermore, based on the apparent change in luminescence color triggered by moisture for EDBEMnBr4, a preliminary attempt is made to apply it to humidity monitoring showing that the boundary of color change has a good linear dependence on humidity and time. This work provides new opportunities for Mn‐based metal halides in both X‐ray detection as well as moisture detection. [ABSTRACT FROM AUTHOR]

The current mainstream planar X‐ray imaging techniques face significant challenges for accurately capturing the internal structure of curved objects, since the variable distances between the curved objects and the flat‐panel scintillation screen cannot eliminate the distortion in X‐ray imaging. Though large‐area and transparent curved scintillation screens are much more desirable. Here, organic–inorganic hybrid Mn‐based single crystals ([CH3Ph3P]2MnX4, X = Cl, Br, I) exhibiting high photoluminescence quantum yield (PLQY) and low melting temperature have been employed to prepare transparent glass for X‐ray scintillation imaging application through a low‐temperature melting strategy. The [CH3Ph3P]2MnBr4‐glass shows high PLQY (47.8%), high‐resolution X‐ray imaging performance (12.3 lp mm−1), low limit of detection (25.33 nGy s−1), and impressive X‐ray irradiation stability (102 Gy). Furthermore, high‐contrast X‐ray imaging at a low dose (6.865 µGy per exposure, 14.5 times lower than the chest radiograph) is achieved. Based on the low glass transition temperature (Tg = 53.6 °C) and easy‐shapeable properties of [CH3Ph3P]2MnBr4‐glass scintillator, the large‐area curved scintillation screen with a series of sizes of Φ 2×4 – Φ 8×4 cm2 can be easily fabricated and show high X‐ray imaging quality. These findings provide a paradigm for future research in shapeable X‐ray scintillators, unlocking new possibilities for curved and 3D X‐ray imaging. [ABSTRACT FROM AUTHOR]

Ultrahigh‐resolution X‐ray detection has always been a goal pursued in industrial inspection and medical diagnosis. However, the resolution of the corresponding image generally suffers from serious light scattering and crosstalk. Here, a low‐temperature thermoplastic scintillator ink of [Bmmim]2MnCl4 (Bmmim = 1‐butyl‐2,3‐dimethylimidazolium) is designed, achieving an astonishing spatial resolution of over 22 lp mm−1 (≥22.5 µm). A customized X‐ray imaging can be realized with the as‐explored [Bmmim]2MnCl4 scintillator to the targets through brushing feasibly exhibiting a high adhesion and processability thanks to the superior rheological properties. It is demonstrated that the coordination number determines the melting point of the corresponding scintillator, and an appropriate melting point (323 K) endows a superior viscosity of the sample as print ink. Accordingly, the as‐explored scintillator not only exhibits a high light output with 3.63 times of the commercial Bi4Ge3O12 (10 000 photons MeV−1) under steady‐state X‐ray illumination but also performs excellent recyclability even after 100 re‐uses. This work brings a new perspective for solving the problems of light scattering and light crosstalk for X‐ray imaging, as well as promoting the development of scintillator ink for recycling utilization. [ABSTRACT FROM AUTHOR]

Scintillators, owing to their exceptional ability to convert high-energy ionizing radiation into visible light, are the core component of X-ray radiography. However, conventional single-crystal scintillators are inadequate to satisfy the modern social and scientific demands. So, the development of novel scintillator materials is imminent. Herein, a series of Na 5 Lu 9- x Gd x F 32 :Ce3+ glass-ceramics (GCs) scintillators were elaborated by an exercisable and low-cost method. Benefiting from the proper introduction of Al powder and Gd3+, as well as the crystallization of Na 5 Lu 9- x Gd x F 32 nanocrystal (NCs) after heat treatment, luminescence excited by ultraviolet and X-ray of the sample is enhanced significantly. The integrated X-ray excited luminescence intensity of the representative sample can reach up to 128% of that of Bi 4 Ge 3 O 12. More importantly, the sample has excellent irradiation stability that is almost undamaged even exposed to high-energy X-ray radiation. Finally, satisfactory X-ray imaging based on the resultant sample was realized. The spatial resolution is as high as 14 lp mm−1, which exceeds that of many novel perovskite scintillators. Thus, this investigation promotes the development of low-cost, stable and high-performing Ce3+-activated GCs scintillators. • Three effective ways were designed to improve the scintillating property of the sample. • The integrated X-ray excited luminescence reaches 128% of that of Bi 4 Ge 3 O 12. • The sample is undamaged even excited by high-power (12 W) X-ray, infering outstanding irradiation stability. • Satisfactory X-ray imaging based on the sample was achieved. • The spatial resolution reaches 14 lp mm−1, exceeding that of many perovskite scintillators. [ABSTRACT FROM AUTHOR]

Scintillators, which can convert high‐energy particles (X‐rays) into detectable low‐energy ultraviolet–visible–near‐infrared photons, are essential components of X‐ray detectors and show extensive practical applications in nondestructive detection and medical imaging. Traditionally, inorganic scintillators represented by CsI:Tl have achieved definite progress. However, the harsh preparation conditions, high production cost, and poor mechanical properties impede their potential development in the high‐end X‐ray imaging field. Organic–inorganic hybrid metal complexes could be excellent alternatives, by virtue of their structural and spectral tunability, good solution processability, and excellent photophysical properties. This review mainly focuses on eco‐friendly lead‐free metal (Mn2+, Cu+, Sb3+, Sn2+, Ge2+, Ln3+, etc.) complex scintillators. The luminescence mechanisms are introduced and the scintillation performance, such as light yield, limit of detection, imaging resolution, etc., is highlighted. Moreover, the current challenges and perspectives in this emerging field are described. It is hoped to provide some theoretical guidance for the continuous development of the new scintillator systems. [ABSTRACT FROM AUTHOR]

Organic thermally activated delayed fluorescent (TADF) scintillators hold promising potential for applications in medical radiography and security detection, but the poor X‐ray absorption ability and inferior radioluminescence (RL) hampered their progression. Herein, the study has pioneered the development of high‐performance TADF Ag(I)‐based scintillators from M2X2(dppb)2 (M = Ag, Cu; X = Cl, Br, I) complexes with 1,2‐Bis(diphenylphosphino)benzene (dppb) ligand. In comparison with Cu(I) complexes, the Ag(I) series generally exhibited superior scintillation performance. Notably, Ag2Cl2(dppb)2 (Ag1) stands out with exceptionally high RL intensity (≈125% higher than that of CsI:Tl) and a low detection limit of 59.8 nGy s−1. The outstanding scintillation performance of Ag1 is primarily attributed to the synergistic effect of the high exciton utilization efficiency origin from a small singlet‐triplet energy gap, enhanced X‐ray absorption capacity by heavy atoms, and the high photoluminescence quantum yield (76.47% in ambient atmosphere). By fabricating a flexible film constructed with Ag1 submicron crystalline powders, a high spatial resolution of 25.0 lp mm−1 for X‐ray imaging is obtained. It offers new opportunities for utilizing TADF metal–organic complexes for highly efficient X‐ray scintillation and imaging. [ABSTRACT FROM AUTHOR]

Doping in luminescent metal halides has become an effective strategy for tailoring the optoelectronic properties. Herein, Cu+ is introduced into Rb2AgBr3 to design the synthesis of Rb2AgBr3:xCu+, which possess cold‐white light emission at room‐temperature without changing the spectral profiles; however, the Cu+ incorporation significantly enhances the photoluminescence quantum efficiency to 98.8% in Rb2AgBr3:0.05Cu+. Additionally, a high scintillation light yield of up to 79 250 photons MeV−1 and a low detection limit of 714.83 nGy s−1 have been achieved via this Cu+ doping engineering. X‐ray imaging with a spatial resolution of up to 5.8 lp mm−1 is further realized using a large scintillator film prepared by mixing polydimethylsiloxane with Cu+ doped Rb2AgBr3 scintillators. This study provides a Cu+ doping design principle for improving both the photoluminescence and scintillation performances of metal halides. [ABSTRACT FROM AUTHOR]

Lead‐free halide perovskite‐based X‐ray scintillators with high light yield (LY) and low detection limit (LOD) have become a growing subject of research interest due to their promising application in a wide range of areas, from security to healthcare. Herein, a modified hot injection method is employed to synthesize Mn(II)‐doped Cs2NaBiCl6 double perovskite nanocrystals (DPNCs) and to examine their scintillating properties for application in X‐ray imaging and detection. The Mn(II)‐doped Cs2NaBiCl6 DPNCs exhibit a broad orange photoluminescence (PL) band at 586 nm with a PL quantum yield of 10.6%, attributed to the 4T2g(4G) → 6A1g(6S) transition of Mn2+. Temperature‐dependent PL and time‐resolved PL spectra of 4.04% Mn(II)‐doped Cs2NaBiCl6 demonstrate that the orange emission intensity initially reaches a maximum and subsequently decreases, while the decay lifetimes monotonically decrease with increasing temperature. This inconsistency can be due to the effect of the [MnCl6]4− octahedra and electron‐phonon coupling at elevated temperatures. Further, 0.05 mm thick Cs2NaBiCl6:4.04%Mn@poly(methyl methacrylate) scintillator film is synthesized with an LY of 28,350 photons MeV−1 and a LOD of 45.2 nGyair s−1. Additionally, this film demonstrates good X‐ray imaging performance with a spatial resolution of 14.76 line pairs (lp) mm−1 and shows exceptional stability under prolonged X‐ray exposure. [ABSTRACT FROM AUTHOR]

The photoluminescent properties of lanthanide complexes have been thoroughly investigated; however, there have been much fewer studies showcasing their potential use in ionizing radiation detection. In this work, we delve into the photo‐ and radio‐induced luminescence of a series of lanthanide‐bearing organic‐inorganic hybrids and their potential as a platform for X‐ray scintillation and imaging. The judicious synergy between lanthanide cations and 2,6‐di(1H‐pyrazol‐1‐yl)isonicotinate (bppCOO−) ligands affords six new materials with three distinct structures. Notably, Eu‐bppCOO‐1 and Tb‐bppCOO‐2 display sharp fingerprint X‐ray‐excited luminescence (XEL), the intensities of which can be linearly correlated with the X‐ray dose rates over a broad dynamic range (0.007–4.55 mGy s−1). Moreover, the X‐ray sensing efficacies of Eu‐bppCOO‐1 and Tb‐bppCOO‐2 were evaluated, showing that Tb‐bppCOO‐2 features a lower detection limit of 4.06 μGy s−1 compared to 14.55 μGy s−1 of Eu‐bppCOO‐1. Given the higher X‐ray sensitivity and excellent radiation stability of Tb‐bppCOO‐2, we fabricated a flexible scintillator film for X‐ray imaging by embedding finely ground Tb‐bppCOO‐2 in the polydimethylsiloxane (PDMS) polymer. The resulting scintillator film can be utilized for high‐resolution X‐ray imaging with a spatial resolution of approximately 7 lp mm−1. [ABSTRACT FROM AUTHOR]

In this study, a pair of chiral manganese(II) complexes is reported based on phosphine oxide, denoted as R/S‐[(L)2MnBr]Br (L = 5,5′‐bis(diphenylphosphine oxide)−4,4′‐bi‐1,3‐benzodioxole). These complexes exhibit distinctive five‐coordinated crystal structures and high stability. In addition, R/S‐[(L)2MnBr]Br display intense red luminescence at room temperature and demonstrate outstanding circularly polarized luminescence property, featuring luminescence dissymmetry factor values of +1.56 × 10−2 and −1.94 × 10−2, respectively. By integrating S‐[(L)2MnBr]Br with commercial phosphors, a white light‐emitting diode is successfully fabricated with a correlated color temperature of 4512 K, achieving a remarkable color rendering index of 96.9. Furthermore, a exceptional scintillation performance is observed in the target compounds and ultimately showcase X‐ray imaging with a spatial resolution of up to 11.9 lp mm−1. This endeavor imparts invaluable insights for the advancement of prospective multifunctional chiral manganese(II)‐based luminescent materials. [ABSTRACT FROM AUTHOR]

Glassy phosphors offer a promising opportunity to overcome the limits of polycrystalline counterparts, thanks to their merits including excellent optical transparency, abandonment of organic binders, and capability of drawing fibers, etc. However, research and development of glassy UV‐C phosphors and fast scintillators have seriously lagged behind crystals. Here, a new type of efficient UV‐C phosphors and fast scintillators (double gain) is developed from Pr3+‐doped transparent nano‐glass composites (nano‐GCs) containing KY3F10 nanocrystals. Such a material combines favorably the advantages of both crystal and glass, exhibiting intense interconfigurational 5d‐4f emissions of Pr3+ upon deep‐UV, high energy electron‐beam and X‐ray excitations. The emission profile ideally overlaps with the germicidal effectiveness curve. The Pr3+‐doped nano‐GCs are endowed with a radiative decay time shorter than that of extensively studied Ce3+‐doped glasses and nano‐GCs. They exhibit intense X‐ray excited radioluminescence that is comparable to the standard Bi4Ge3O12 (BGO) crystal and significantly stronger than Pr3+‐doped ZBLAN fluoride glass known for the high luminescence efficiency. An X‐ray imaging system with a good spatial resolution using the Pr3+‐doped nano‐GCs is also demonstrated. [ABSTRACT FROM AUTHOR]

Zinc halides have been less explored even though they are a promising lead‐free family with the merits of environmental friendliness and low cost. Here, the organic–inorganic hybrid zinc halides are screened with aromatic molecules containing amino groups (MXDA: m‐Xylylenediamine, ABI: 2‐Aminobenzimidazole, pipda: 2‐piperidylmethylamine, p‐MPEA: p‐Methylphenethylamine), and six new compounds are discovered: (MXDA)ZnCl4 (1), (ABI)2ZnCl4 (2), (pipda)2H2OZnCl2 (3), [(pipda)4Zn2Br4]·H2O (4), (p‐MPEA)2ZnCl4 (5), and (p‐MPEA)2ZnBr4 (6). The discovered compounds exhibit diverse efficient light emissions (blue, green, yellow, and ultraviolet) under ultraviolet light irradiation. By doping Sb and Mn at the Zn site, (MXDA)ZnCl4 exhibits different colors of light under excitation light of different wavelengths, so it is successfully used for anti‐counterfeiting. (MXDA)Zn0.91Mn0.09Cl4 is also found to be an efficient X‐ray scintillator for X‐ray imaging. Among the as‐explored new phases, a maximum photoluminescent quantum yield of 82.60% is realized, enabling the utilization for white light‐emitting diodes. The results suggest that the zinc halides are a new lead‐free family with superior optoelectronic properties, which can be used for multiple applications. [ABSTRACT FROM AUTHOR]

Flat-panel x-ray scintillators with a high spatial resolution at a low radiation dose rate are desirable for efficient imaging applications in medical diagnostics, security inspection, and nondestructive inspection. To promote the progress of x-ray imaging technologies, it is of great interest to explore transparent scintillators with reduced light scattering, high light yields, and uniform radioluminescence. Herein, we design and prepare a novel lead-free (C12H28N)2Cu2I4 metal halide featuring a high luminescent efficiency and white emission benefiting from the double self-trapped exciton mechanism, which enable to not only match the response of semiconductor-based sensors but also enhance light yields and decrease exposed doses to objects. Furthermore, transparent, and flexible scintillators with large areas of 20.25 cm2 demonstrate an outstanding scintillation performance including a high spatial resolution of 19.8 lp mm−1 and an ultralow detection limit of 28.39 nGyair s−1, which are ∼4 times higher and 194 times lower than typical values for medical imaging, respectively. This work provides not only a new route to explore promising alternatives with broadband emission but also a novel opportunity to develop flexible x-ray imaging technology. [ABSTRACT FROM AUTHOR]

X‐ray radiography, playing a crucial role in the daily life of humans, extends the application landscapes of perovskites. Lead halide perovskites remain superior candidates because of strong X‐ray absorption and effective conversion of X‐ray to visible photons. Unfortunately, the perovskites exhibiting efficient band‐edge emission (3D, quasi‐2D or 2D) usually suffer from severe self‐absorption, while the perovskites showing broadband emission with large Stokes shift (0D, 1D or 2D) usually have low quantum yield, long afterglow or poor solution‐processability. Halide‐intercalated perovskites, with incorporated halides in organic layers, exhibit attractive optoelectronic properties due to reduced confinement of excitons, but their development falls far behind due to limited molecular design strategies and wet‐chemistry methods. Here, the use of universal‐wet‐chemistry‐synthesized novel halide‐intercalated perovskites as an efficient X‐ray scintillator for X‐ray imaging is reported. These novel perovskites exhibit superior luminescence by exploiting both free and self‐trapped excitons via halide intercalation. Accordingly, such perovskite scintillators present higher radioluminescence performance compared with conventional perovskite scintillators through enhanced radiative recombination and suppressed self‐absorption simultaneously. With such a scintillator screen, high‐performance X‐ray imaging is demonstrated. The results not only represent a universal synthesis route for the development of perovskites, but also provide valuable guidance for high‐performance X‐ray radiography. [ABSTRACT FROM AUTHOR]

The study of facile‐synthesis and low‐cost X‐ray scintillators with high light yield, low detection limit and high X‐ray imaging resolution plays a vital role in medical and industrial imaging fields. However, the optimal balance between X‐ray absorption, decay lifetime and excitonic utilization efficiency of scintillators to achieve high‐resolution imaging is extremely difficult due to the inherent contradiction. Here two thermally activated delayed fluorescence (TADF)‐actived coinage‐metal clusters M6S6L6 (M=Ag or Cu) were synthesized by simple solvothermal reaction, where the cooperation of heavy atom‐rich character and TADF mechanism supports strong X‐ray absorption and rapid luminescent collection of excitons. Excitingly, Ag6S6L6 (SC‐Ag) displays a high photoluminescence quantum yield of 91.6 % and scintillating light yield of 17420 photons MeV−1, as well as a low detection limit of 208.65 nGy s−1 that is 26 times lower than the medical standard (5.5 μGy s−1). More importantly, a high X‐ray imaging resolution of 16 lp/mm based on SC‐Ag screen is demonstrated. Besides, rigid core skeleton reinforced by metallophilicity endows clusters M6S6L6 strong resistance to humidity and radiation. This work provides a new view for the design of efficient scintillators and opens the research door for silver clusters in scintillation application. [ABSTRACT FROM AUTHOR]

The urgency for cost‐effective, high‐resolution, flexible X‐ray imaging detectors is generating great demand for scintillators with low‐temperature processability, high scintillation yield, and negligible afterglow. X‐ray imaging materials are currently dominated by inorganic scintillators in the form of rigid films and bulk crystals, which have inherent limitations including high‐temperature, complex synthesis, and considerable challenges toward advanced nonplanar imaging. Here, high‐performance and flexible X‐ray scintillators based on novel zero‐dimensional (0D) (BTPP)2MnX4 (BTPP = benzyltriphenylphosphonium; X = Cl, Br) halides are reported. They emit bright green light originating from the 4T1‐6A1 transition of Mn2+ under X‐ray excitation. In particular, (BTPP)2MnBr4 single crystals exhibit excellent air‐ and radiation‐stability, a high scintillation yield of 53 000 photons MeV−1, a low detection limit of 89.9 nGyair s−1, and an ultralow afterglow comparable to commercial Bi4Ge3O12 (BGO) single crystals. Moreover, the (BTPP)2MnCl4@polydimethylsiloxane (PDMS) flexible scintillation screens achieve a high spatial resolution of 14.1 lp mm−1 and realize high‐quality imaging results of nonplanar objects. This study demonstrates that the flexible scintillation screens based on low‐dimensional Mn(II) hybrid halides have significant potential for low‐dose and high‐resolution X‐ray imaging applications. [ABSTRACT FROM AUTHOR]

Large‐sized transparent scintillators with a high photoluminescent quantum yield (PLQY) and self‐absorption‐free properties are highly desired to achieve high spatial resolution X‐ray imaging. In this research, a transparent 0D organic–inorganic (ETP)2SbCl5 (ETP = Ethyl triphenylphosphine) amorphous wafer is developed by melting the ETPCl and SbCl3 mixture and then undergoing a quenching process. The obtained amorphous wafer exhibits a high light transmittance of 86% in the range of 450–800 nm. It also shows a light emission peak at 624 nm, a Stokes shift of 259 nm, and PLQY approaching unity (99.3%). These properties enable it to produce X‐ray images with a high spatial resolution of 19.0 lp mm−1 at a modulation transfer function (MTF) value of 0.2, among the best values reported. Additionally, it also shows remarkable stability under continuous X‐ray illumination. Its unique optical properties and ability to be processed in large sizes make the organic–inorganic metal halide transparent wafer a promising scintillator. This also demonstrates the potential application of the melt‐quenching method in fabricating highly luminescent, low‐electronic‐dimensional metal halide wafers. [ABSTRACT FROM AUTHOR]

With the increasing demands of X‐ray detection and medical diagnosis, organic scintillators with intense and tunable X‐ray excited emission have been becoming important. To guarantee the X‐ray absorption, heavy atoms were widely added in reported organic scintillators, which led to emission quenching. In this work, we propose a new strategy to realize organic scintillators through the host‐guest doping strategy. Then the X‐ray absorption centers (host) and emission centers (guest) are separated. Under X‐ray excitation, these materials displayed intense and readily tunable emissions ranging from green (520 nm) to near infrared (NIR) regions (682 nm). Besides, the relationship between the X‐ray absorption and spatial arrangement of the heavy atoms in the host matrix was also revealed. The potential application of these wide‐range color tunable organic host‐guest scintillators in X‐ray imaging were demonstrated. This work provides a new feasible strategy for constructing high‐performance organic scintillators with tunable luminescence properties. [ABSTRACT FROM AUTHOR]

Lead perovskite nanocrystals (PNCs) have shown great potential for optoelectronic device applications due to their excellent optoelectronic properties. However, the application of PNCs is significantly limited due to the inferior stability resulting from the highly dynamic ligands on the surface. Herein, poly(maleic anhydride‐alt‐1‐octadecene) (PMAO) with low molecular weight (Mn = 1911) is synthesized by copolymerization and used as multi‐dentate ligands to prepare CsPbBr3 PNCs via hot injection. The PNCs exhibit excellent water resistance, which maintains fluorescence for 2600 min while conventional PNCs are completely destroyed after 100 min. Density functional theory calculations demonstrate that PMAO as a multi‐dentate ligand has higher adsorption energy to the surface of PNCs. Due to the large amount of extra anhydride structure of PMAO, PMAO‐PNCs are used as a cross‐linking agent to directly prepare flexible films by an in situ one‐step polymerization reaction with 1,3‐bis(3‐aminopropyl) polydimethylsiloxane (PDMS‐NH2). The fluorescent flexible films show great potential for applications including X‐ray imaging scintillators and flexible light‐emitting diodes (LEDs). This study can provide guidance to prepare ultra‐stable PNCs and flexible perovskite films with good stability in a simple and efficient way. [ABSTRACT FROM AUTHOR]

Copper‐based halides have emerged as promising scintillator materials for X‐ray imaging due to their favorable photophysical characteristics, such as negligible self‐absorption, high light output, and fast decay. Among these materials, Cs3Cu2I5, a blue emitter, currently delivers the highest scintillation light output under steady‐state X‐rays. However, there is a significant spectral mismatch between its emission band and the spectral responsivity of regular flat‐panel photodiode arrays. In this study, a comprehensive analysis of the physical properties of the CsCu2I3 scintillator is conducted, and its perfect spectral compatibility is discovered, which results in a higher photodiode signal despite its relatively lower light output compared to typical Cs3Cu2I5 scintillators. Furthermore, CsCu2I3 exhibits faster light decay properties, making it especially suitable for Computed Tomography (CT) X‐ray imaging. High‐quality X‐ray cone beam computed tomography (CBCT) imaging is successfully demonstrated using the fast‐decaying CsCu2I3 scintillator screen. Additionally, the flexibility of the scintillator allows for non‐planar imaging, showcasing advantages not available with traditional rigid scintillators. These results not only highlight the significant promise of the CsCu2I3 scintillator but also emphasize the necessity of considering spectral compatibility when designing novel scintillator materials. [ABSTRACT FROM AUTHOR]

Conventional scintillator‐based X‐ray imaging typically captures the full spectral of X‐ray photons without distinguishing their energy. However, the absence of X‐ray spectral information often results in insufficient image contrast, particularly for substances possessing similar atomic numbers and densities. In this study, an innovative multi‐energy X‐ray linear‐array detector is presented that leverages side‐illuminated X‐ray scintillation using the emerging metal halide Cs3Cu2I5. The negligible self‐absorption characteristic not only improves the scintillation output but is also beneficial for improving the energy resolution for the side‐illuminated scintillation scenarios. By exploiting Beer's law, which governs the absorption of X‐ray photons with different energies, the incident X‐ray spectral can be reconstructed by analyzing the distribution of scintillation intensity when the scintillator is illuminated from the side. The relative error between the reconstructed and measured X‐ray spectral is < 5.63%. This method offers an additional energy‐resolving capability for X‐ray linear‐array detectors commonly used in computed tomography (CT) imaging setups, surpassing the capabilities of conventional energy‐integration approaches, all without requiring extra hardware components. A proof‐of‐concept multi‐energy CT imaging system featuring eight energy channels is successfully implemented. This study presents a simple and efficient strategy for achieving multi‐energy X‐ray detection and CT imaging based on emerging metal halides. [ABSTRACT FROM AUTHOR]

Metal‐halide perovskites have emerged as one of the most promising contenders for the next‐generation X‐ray scintillators on account of their large absorption coefficients, high light yields, and low‐cost fabrication. However, the existing X‐ray scintillators are plagued either by poor stability or high toxicity. Here, highly stable and flexible CsCu2I3@polymethyl methacrylate (PMMA) composite films are fabricated simply by a facile one‐step drop‐coating technique. Benefiting from the reasonable light yields (24 100 photons MeV−1), short photoluminescence decay time (207 ns), and flat surface, a low detection limit of 39 nGyair s−1 and a record‐high resolution of up to 25 lp mm−1 are demonstrated in these CsCu2I3@PMMA composite films. The X‐ray imaging tests show that the CsCu2I3@PMMA composite films display excellent properties in the dynamic and irregular objects imaging. In addition, the CsCu2I3@PMMA composite films exhibit a desirable endurance to the high‐energy X‐ray's irradiation and the water erosion (photoluminescence quantum yield remains up of 90% of its initial value even after submersion in water for 300 h). This work provides a potential to develop eco‐friendly and highly stable halide perovskite materials for high‐resolution X‐ray imaging. [ABSTRACT FROM AUTHOR]

Metal halide crystals are bright but hygroscopic scintillator materials that are widely used in X‐ray imaging and detectors. Precipitating them in situ in glass to form glass ceramics (GCs) scintillator offers an efficient avenue for large‐scale preparation, high spatial resolution, and excellent stability. However, precipitating a high fraction of metal halide nanocrystals in glass to maintain high light yield remains a challenge. Herein, an ionic‐covalent hybrid network strategy for constructing GCs scintillator with high crystallinity (up to ≈37%) of BaCl2: Eu2+ nanocrystals is presented. Experimental data and simulations of glass structure reveal that the Ba2+‐Cl− clustering promotes the high crystallization of BaCl2 nanocrystals. The ultralow phonon energy (≈200 cm−1) of BaCl2 nanocrystals and good Eu reduction effect enable high photoluminescence inter quantum efficiency (≈80.41%) in GC. GCs with varied crystallinity of BaCl2: Eu2+ nanocrystals demonstrate efficient radioluminescence and tunable scintillator performance. They either outperform Bi4Ge3O14 single crystal by over 132% steady‐state light yield or provide impressive X‐ray imaging resolutions of 20 lp mm−1. These findings provide a new design strategy for developing bright transparent GCs scintillators with a high fraction of metal halide nanocrystals for X‐ray high‐resolution imaging applications. [ABSTRACT FROM AUTHOR]

High‐resolution X‐ray imaging is increasingly required for medical diagnosis and large‐area detection. However, the issues of scattering and optical crosstalk are limiting the spatial resolution of the indirect X‐ray imaging. In this study, a feasible and efficient strategy is proposed to in situ synthesize flexible Cs3Cu2I5:2%In+@paper as a superior scintillator film, which can be scaled up to an ultra‐large area of 4800 cm2. The as‐obtained Cs3Cu2I5:2%In+@paper performs a fascinating photoluminescence quantum efficiency up to 88.14%, a steady state light yield of 70169 photons/MeV, and spatial resolution of 15 lp mm−1. Moreover, the suppressed physical scattering and optical crosstalk of the corresponding film are demonstrated. Accordingly, this work explores a feasible fabrication of customizable scintillation films with large area for high‐resolution X‐ray detection. [ABSTRACT FROM AUTHOR]

The resulting image obtained from an X-ray imaging system depends significantly on the characteristics of the detector. In particular, when an X-ray image is acquired by thinning the detector, a relatively large amount of noise inevitably occurs. In addition, when a thick detector is used to reduce noise in X-ray images, blurring increases and the ability to distinguish target areas deteriorates. In this study, we aimed to derive the optimal X-ray image quality by deriving the optimal noise reduction parameters based on the non-local means (NLM) algorithm. The detectors used were of two thicknesses (96 and 140 μm), and images were acquired based on the IEC 62220-1-1:2015 RQA-5 protocol. The optimal parameters were derived by calculating the edge preservation index and signal-to-noise ratio according to the sigma value of the NLM algorithm. As a result, a sigma value of the optimized NLM algorithm (0.01) was derived, and this algorithm was applied to a relatively thin X-ray detector system to obtain appropriate noise level and spatial resolution data. The no-reference-based blind/referenceless image spatial quality evaluator value, which analyzes the overall image quality, was best when using the proposed method. In conclusion, we propose an optimized NLM algorithm based on a new method that can overcome the noise amplification problem in thin X-ray detector systems and is expected to be applied in various photon imaging fields in the future. [ABSTRACT FROM AUTHOR]

Despite the extraordinary X‐ray scintillation performance of three‐dimensional (3D) lead perovskite nanocrystals (PNCs), the serious biotoxicity of Pb2+ and luminescent instability in water remain insurmountable obstacles for their applications in medical imaging. To address these drawbacks, herein, the study demonstrates one new lead‐free zero‐dimensional (0D) hybrid cuprous halide of single‐crystalline [BzTPP]2Cu2I4 (BzTPP = Benzyltriphenylphosphonium) as a satisfactory X‐ray scintillator. [BzTPP]2Cu2I4 displays broadband yellowish‐green light emission with a high photoluminescent quantum yield (PLQY) of 44.2% and large Stokes shift of 167 nm upon UV light excitation. High PLQY and negligible self‐absorption enable [BzTPP]2Cu2I4 to display impressive scintillation performance excited by X‐ray with a light yield of 27 706 photons MeV‐1 and low detection limit of 0.352 µGy s−1, surpassing typical 3D PNCs. More importantly, [BzTPP]2Cu2I4 represents extraordinary structural and luminescent stability in water for at least one month. The excellent and stable radioluminescence performance as well as solution growth method ensure a [BzTPP]2Cu2I4‐based screen for fine‐resolution X‐ray imaging with potential in radiography and inspection. This work highlights the multiple merits of low‐toxicity and cost, high light yield, and long‐term water‐stability of 0D hybrid cuprous halides as highly desirable X‐ray scintillators. [ABSTRACT FROM AUTHOR]

Lead‐free metal halides have recently received sustained attention because of their nontoxicity, low‐cost, as well as excellent stability and optoelectronic properties. However, most of the reported lead‐free metal halides are synthesized via slow solution‐processing at high temperature in toxic solvents, which may impede their commercial applications. Here, a solvent‐free strategy is proposed to synthesize inorganic rubidium copper halides (Rb2CuX3, X = Cl, Br) at room temperature, which exhibit efficient violet emission dominated by a self‐trapped excitons (STEs) mechanism and attractive stabilities against ultraviolet illumination and heating. Thus, Rb2CuX3 powders are employed as emitters and scintillators applied in wireless light communication and X‐ray imaging technologies. Under orthogonal frequency division multiplexing modulation, emitters demonstrate a broad −3 dB bandwidth of 26.3 MHz and a high received data rate of 205.1 Mbps. Additionally, flexible scintillation films based on as‐prepared powders are fabricated and show outstanding X‐ray scintillation properties, including a high spatial resolution of 18.1 lp mm−1 and a low detection limit of 104 nGyair s−1, as well as promising imaging performance for irregular objects. These results suggest large‐scale production of nontoxic Rb2CuX3 and their potential commercialization in fields of high‐speed light communication and X‐ray radiography. [ABSTRACT FROM AUTHOR]

Eco‐friendly lead‐free organic–inorganic manganese halides (OIMHs) have attracted considerable attention in various optoelectronic applications because of their superior optical properties and flexible solution processibility. Herein, we report a novel pseudo‐2D layered OIMH (MTP)2MnBr4 (MTP: methyltriphenylphosphonium), which exhibits intense green emission under UV/blue or X‐ray excitation, with a near‐unity photoluminescence quantum yield, high resistance to thermal quenching (I150 °C=84.1 %) and good photochemical stability. These features enable (MTP)2MnBr4 as an efficient green phosphor for blue‐converted white light‐emitting diodes, demonstrating a commercial‐level luminous efficiency of 101 lm W−1 and a wide color gamut of 116 % NTSC. Moreover, these (MTP)2MnBr4 crystals showcase outstanding X‐ray scintillation properties, delivering a light yield of 67000 photon MeV−1, a detection limit of 82.4 nGy s−1, and a competitive spatial resolution of 6.2 lp mm−1 for X‐ray imaging. This work presents a new avenue for the exploration of eco‐friendly luminescent OIMHs towards multifunctional light‐emitting applications. [ABSTRACT FROM AUTHOR]

Nano-glasses are next-generation scintillators combining favorably the merits of both scintillator crystals and glasses. Here, a new nano-glass scintillator is prepared embedding CsGd 2 F 7 :Ce3+ nanocrystals (NCs). The microscopic morphology, particle size, and distribution of the NCs are studied by high resolution transmission electron microscopy. Significantly enhanced radioluminescence efficiency is obtained in the nano-glasses. The largest integrable intensity of X-ray excited luminescence is 316% of the standard Bi 4 Ge 3 O 12 (BGO) crystal. A well-resolved full-energy peak with an energy resolution of 17.4% is registered for the 662 keV gamma rays, and the light yield is determined to be 827 ± 8 ph/MeV. The nano-glass scintillators exhibit good radiation hardness and thermal stability. As a proof of concept, an X-ray imaging system of a good resolution is built on the nano-glass scintillators. [ABSTRACT FROM AUTHOR]

Compared with commercial bulk scintillators and halide perovskites, lanthanide-doped fluoride nanoscintillators (NSs) exhibit high photochemical stability, low bio-toxicity and tunable emissions. However, the widely employed hosts, such as NaGdF4, NaLuF4 and NaYF4, need many expensive rare earth salts and time-consuming reaction processes. In this work, lanthanide-doped NaBiF4 NSs were prepared by a facile rapid room-temperature reaction method. The obtained NSs present a hollow structure, strong scintillation intensity and ultra-weak afterglow. The scintillation intensity was enhanced by incorporating Gd3+ ions, but it was decreased after codoping with Ho3+ or Er3+ ions. By employing a NaBiF4:15Tb/10Gd NS integrated thin film as a nanoscintillator screen, a high spatial resolution of 12.5 lp mm−1 was achieved. Our results could promote the exploration of new kinds of NSs with low cost, high production and superior performances. [ABSTRACT FROM AUTHOR]