The physical properties of scintillators determine X‐ray detection performance directly, which plays a vital role in computed tomography (CT) imaging for medical radiography and security checks. Recently, lead halide perovskite materials have shown higher photoluminescence quantum yield (PLQY) than conventional X‐ray scintillators, but there are still some limitations, including instability and the use of heavy metal lead. In this study, a low‐temperature solution method is used to prepare 0D lead‐free Cs3Cu2I5 perovskite nanocrystals (NCs), and a corresponding optical fiber panel with Cs3Cu2I5 NCs is fabricated for high‐resolution X‐ray CT imaging. The Cs3Cu2I5 NCs exhibit a high PLQY of 59% and outstanding stability for more than three months. Importantly, the Cs3Cu2I5 NCs show a high radioluminescence (RL) light yield, that is four times higher than that of CsPbBr3 NCs (80 kV, 70 µA). In addition, an X‐ray detector based on a Cs3Cu2I5 NC scintillator is designed. Using this system, a clear projection image of a chip is obtained, and a 3D CT image of a snail is reconstructed. Therefore, the use of lead‐free perovskite nanocrystal scintillators is a promising technique for commercial X‐ray detection.

Nowadays, there is much attention focusing on lead halide perovskite because of its admirable performances in optoelectronic applications. However, the notorious toxicity and long-term instability are two main factors limiting its widespread applications. The findings of this work demonstrate a facile synthesis process for novel lead-free CsAgCl 2 perovskite microcrystals with no organic ligand involved. The fundamental properties of the CsAgCl 2 microcrystals are revealed by applying temperature-dependent X-ray diffraction and photoluminescence measurements from 77 to 300 K. Furthermore, the CsAgCl 2 microcrystals exhibit excellent air (60 days), thermal (100 °C), and light stability. Meanwhile, the CsAgCl 2 microcrystals have shown exciting potential applications in the fields of photocatalysis and photoelectrochemistry.

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The growth and rupture of conductive filaments act a crucial part in the reliability of resistive switching behaviors. The random growth and rupture of conductive filaments are the primary reason for the instability of set/reset reproducibility. Hence, we propose a method that embedded carbon quantum dots (CQDs) in polymethylmethacrylate (PMMA) to fabricate the Ag/PMMA&CQDs/FTO resistive switching device. Five different concentrations of CQDs are embedded in PMMA to regulate the resistive switching properties, and the resistive memory characteristics of the optimal group are systematically studied. The optimal group exhibits excellent switching repeatability, low set/reset voltages, and stable forming voltage, which is much better than PMMA without CQDs. Furthermore, we employ the COMSOL software to build a simulation model for exploring the influence of CQDs on the internal electric field of PMMA, which proved that the introduction of CQDs might have a favorable effect on the orderly growth of conductive filaments.

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As an effective electron transport layer, tin oxide (SnO2) has attracted much attention owing to its charge mobility and chemical stability, but it still suffers from high trap at the SnO2/perovskite interface. Herein, a simple interface treatment strategy of diethylenetriaminepentakis (methylphosphonic acid) (DETAPMP) to effectively passivate the SnO2/MAPbI3–x Cl x interface is reported. Under the optimal DETAPMP concentration, the average power conversion efficiency (PCE) of MAPbI3–x Cl x solar cells is improved from 17.27 to 19.41% and the champion device shows a PCE of 20.02%. In the (FAPbI3)0.95(MAPbBr3)0.05 system, the average PCE can be improved from 20.08 to 20.95% and the champion device shows a PCE of 21.65%. Such an enhancement is mainly attributed to two factors: (1) the phosphate group in DETAPMP reacts with SnO to passivate SnO2 defects and (2) the ammonium group in DETAPMP is expected to balance the PbI3 – charge and passivate PbI3 – defects, thus achieving lower charge recombination and better carrier transport. In addition, due to the hydrophobicity of DETAPMP and the reduced grain boundaries in the perovskite film, the long-term stability of the perovskite with DETAPMP-modified SnO2 is improved under the ambient conditions with 20–30% humidity.

Organic–inorganic hybrid perovskites are inexpensive materials with desirable characteristics of color-tunable and narrow-band emissions for lighting and display technology. To improve the luminescence efficiency, it is mandatory to understand the luminescence mechanism in organic–inorganic hybrid perovskites. In this study, organic–inorganic hybrid perovskite films with different A-site components including CH3NH3 + (MA+), NH2CHNH2 + (FA+), CH3CH2NH3 + (EA+), and CH3CH2CH2NH3 + (PA+) were prepared to study the mechanism of fluorescence quenching related to A-site organic cations. An interesting phenomenon is that a EABr:PbBr2 film with two carbons emits only weak light, while a MABr:PbBr2 film with only one carbon, a PABr:PbBr2 film with three carbons, and a FABr:PbBr2 film with two nitrogens at both ends emit bright light. The calculated results by density functional theory show that the partial charge densities for EAPbBr3 and EA4Pb3Br10 are very localized, which means that they can capture electrons or holes and become nonradiative recombination centers. Meanwhile, the evident changes in the Pb–Br–Pb bond lengths, small free volume, and the strong CH3 vibration indicate that EA+ is more likely to collide with the PbBr3 – cavity formed by eight adjacent corner-sharing PbBr6 4– octahedra, enhancing electron–phonon coupling, which leads to serious fluorescence quenching.

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