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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]

Real‐time in vivo detection of cancer via attenuation‐based plain X‐ray imaging is proposed to fundamentally overcome the penetration depth limits of current fluorescence‐based imaging techniques. Using cesium lead bromide (CsPbBr3, CPB) quantum dot (QD) scintillators, real‐time X‐ray detection of 5 mm‐sized Panc‐1 cell tumors grown in a mouse is successfully performed. The QDs are rapidly co‐synthesized and double‐encapsulated with silicon dioxide (SiO2) to completely prevent them from being aggregated, decomposed, or released; they are then conjugated with antibodies to target pancreatic cancer. Due to the dramatic X‐ray attenuation, the X‐ray signal from the CPB QDs placed under the 2 cm‐thick tissue is clearly observed, while their fluorescence signal is not detected at all. In in vivo mouse experiments, the injection of a tiny amount (2.8 μg on a QD basis) of the CPB–SiO2@SiO2–Ab nanoparticles gives rise to a bright spot at the location of the tumor. Cell viability assay and histological analysis confirm the biocompatibility and nontoxicity of the nanoparticles. [ABSTRACT FROM AUTHOR]