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Fast neutron and X‐ray imaging are considered complementary nondestructive detection technologies. However, due to their opposite cross‐sections, development of a scintillator that is sensitive to both fast neutrons and X‐rays within a single‐material framework remains challenging. Herein, an organic–inorganic hybrid perovskite (C4H9NH3)2PbBr4 (BPB) is demonstrated as a scintillator that fully meets the requirements for both fast neutron and X‐ray detection. The hydrogen‐rich organic component acts as a fast neutron converter and produces detectable recoil protons. The heavy atom‐rich inorganic fraction efficiently deposits the energy of charged recoil protons and directly provides a large X‐ray cross‐section. Due to the synergy of these organic and inorganic components, the BPB scintillator exhibits high light yields (86% of the brightness of a commercial ZnS (Ag)/6LiF scintillator for fast neutrons; 22 000 photons per MeV for X‐rays) and fast response times (τdecay = 10.3 ns). More importantly, energy‐selective fast neutron and X‐ray imaging are also demonstrated, with high resolutions of ≈1 lp mm−1 for fast neutrons and 17.3 lp mm−1 for X‐rays; these are among the highest resolution levels for 2D perovskite scintillators. This study highlights the potential of 2D perovskite materials for use in combined fast neutron and X‐ray imaging applications. [ABSTRACT FROM AUTHOR]

Halide perovskites are an emerging scintillator material for X‐ray imaging. High‐quality X‐ray imaging generally requires high spatial resolution and long operation lifetime, especially for targeted objects with irregular shapes. Herein, a perovskite "polymer–ceramics" scintillator, in which the halide perovskite nanocrystals are grown inside a pre‐solidified polymer structure with high viscosity (6 × 1012 cP), is designed to construct flexible and refreshable X‐ray imaging. A nucleation inhibition strategy is proposed to prevent the agglomeration and Ostwald ripening of perovskite crystals during the subsequent precipitation process, enabling a high‐quality polymer–ceramics scintillator with high transparency. This scintillator‐based detector achieves a detection limit of 120 nGy s–1 and a spatial resolution of 12.5 lp mm–1. Interestingly, due to the anchoring effect of the exfoliated atoms provided by the polymer matrix, the scintillator film can be refreshed after a long duration (≥3 h) and high dose (8 mGy s–1) irradiation. More importantly, this inherent characteristic overcomes the long operation lifetime issue of perovskites‐based scintillators. Hence, the authors' exploration of the polymer–ceramics scintillator paves the way for the development of flexible and durable perovskite scintillators that can be produced at a low operation cost. [ABSTRACT FROM AUTHOR]

Both semiconductors and scintillators have their own advantages in direct and indirect X‐ray detection, respectively. However, they are also limited by their intrinsic properties and detection mechanisms. Here, a low‐cost and large‐area flat X‐ray detector is reported by combining a cesium silver bismuth bromide (Cs2AgBiBr6) perovskite semiconductor with a ethylenebis‐triphenylphosphonium manganese (II) bromide ((C38H34P2)MnBr4) scintillator through fast tableting processes. Cs2AgBiBr6 and (C38H34P2)MnBr4 can attenuate the X‐ray photons to induce charge carriers that are collected through the continuous Cs2AgBiBr6 grains. (C38H34P2)MnBr4 blocks the Cs2AgBiBr6 ions migration paths at the grain boundaries to reduce the device dark current/noise and improves the working stability. Most charges generated by (C38H34P2)MnBr4 are transferred to the adjacent Cs2AgBiBr6, and recombined charges radiate light through scintillation, which will be further absorbed by the surrounding Cs2AgBiBr6 perovskite, and further induce collectable charges for indirect X‐ray detection, avoiding the unwanted light scattering, self‐absorption, or afterglow effects of scintillators. The hybrid X‐ray detector displays a high sensitivity of 114 µC Gyair−1 cm−2 to 120 keVp hard X‐rays with a lowest detectable dose rate of 0.2 μGyair s−1, showing 75 times lower detection limit compared to (C38H34P2)MnBr4 scintillator, which provides a new path for X‐ray flat‐panel design. [ABSTRACT FROM AUTHOR]

Scintillators for radiation detection are of great significance in medical imaging, security, and nondestructive inspection. The current challenge for scintillators is to simultaneously achieve high scintillation light yield, fast radioluminescence, simple film fabrication, large X‐ray attenuation efficiency as well as stable and nontoxic compositions; no previous scintillators fulfill all the above requirements. Here, metal halide Rb2AgBr3, possessing defect‐bound excitonic radioluminescence, is shown as efficient and fast scintillators. This nontoxic and stable scintillator emits from excitons bound to neutral bromine vacancies, enjoying an efficient and spin‐allowed fast emission with minimized self‐absorption. Rb2AgBr3 thus has a high light yield (25 600 photons MeV−1), fast scintillation decay time (5.31 ns), and a record value of light yield versus decay time (4821 photons MeV−1 ns−1). The close‐space sublimation method is developed for fast and scalable fabrication of oriented Rb2AgBr3 films. The scintillator film is further integrated with commercial flat‐panel imagers, and the spatial resolution reaches 10.2 line pairs per millimeter at the modulation transfer function of 0.2, doubling the resolution of conventional CsI:Tl flat‐panel detectors. The dynamic X‐ray imaging and its use to real‐time monitoring of bone movement without ghosting effect is also demonstrated. [ABSTRACT FROM AUTHOR]

Thrombosis is a frequent predisposing factor in high‐mortality cardiovascular diseases, which underscores the urgent need to precisely diagnose thrombosis formation at a less severe stage. However, it is still challenging to realize in vivo early thrombosis imaging due to lack of high sensitivity/‐specificity molecular imaging strategy. To address such problems, thrombin‐activatable scintillating nanoprobes are developed for background‐free X‐ray‐excited luminescence (XEL) imaging of in vivo early thrombosis. The nanoprobes are constructed by designing bright XEL‐emitting lanthanide‐doped scintillator nanocrystals (NCs) with dye labeled‐peptide modification. Such nanoprobes show XEL‐off originally and enable robust turn‐on XEL upon thrombin‐specific cleavage of the peptide, resulting from the rational manipulation of energy transfer between dye and NCs. Specially, due to high tissue penetration depth and background‐free attributes in XEL imaging, this strategy achieves high‐efficiency XEL imaging of the early thrombosis on the basis of in situ elevated thrombin levels. Moreover, XEL and magnetic resonance imaging capabilities can be integrated to further improve imaging accuracy and monitor thrombosis progression. As such, the exploited strategy demonstrates a novel paradigm for realizing timely thrombosis imaging and provides a new readily tailorable platform for sensitive in vivo deep‐tissue imaging. [ABSTRACT FROM AUTHOR]