Perovskite nanocrystals (PNCs) offer unique advantages in large-area and thick-film deposition for X-ray detection applications due to the decoupling of the crystallization of perovskite from film formation, as well as their low-temperature and scalable deposition methods. However, the partial detachment of long-chain ligands in PNCs during the purification process would lead to the exposure of surface defects, making it challenging to ensure efficient charge carrier extraction and stable X-ray detection. In this study, we propose a beneficial strategy that involves the in situ reparation of these exposed defects with sodium bromide (NaBr) during the purification process to construct CsPbBr PNC-organic bulk heterostructure X-ray detectors. The NaBr-passivated PNCs exhibit stronger photoluminescence intensity and lower trap density in films compared to those of the control samples, confirming the effective passivation of halide vacancy defects. Furthermore, the NiO hole transport layer with remarkable electron blocking capability is introduced to further suppress the dark current of the devices. Consequently, the optimal devices exhibit a large sensitivity of 4237 μC Gy cm and a low dark current density of 10 nA cm, as well as improved operational stability, which allows for high-contrast and low-dose X-ray imaging applications.
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http://dx.doi.org/10.1021/acsami.4c01567 | DOI Listing |
iScience
December 2024
Center for Reproductive Medicine and Obstetrics & Gynecology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China.
Thermodynamic theory suggests that the obvious mechanical behavior caused by temperature and interlayer angle will affect the physical properties of materials, such as mechanical properties and transportation behavior, and it is different from the behavior in three-dimensional bulk materials. We observe an abnormal physical effect of bilayer graphene/hexagonal boron nitride (G/BN)-carbon nanotube (CNT) heterostructures, with a normalized out-of-plane deformation and normalized bond angle percentage to almost several times higher those of pristine G/BN heterostructures (without CNT) at 700-800 K. Our combined finite element theory and molecular dynamics simulations confirmed that the combination of CNT and interlayer angle diverted and bridged the propagating crack and provided a stable crack propagation path and crack tip opening displacement, resulting in the stress fields to be controlled around the CNT at high temperature.
View Article and Find Full Text PDFAdv Mater
December 2024
Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China.
Through the stacking technique of 2D materials, the interfacial polarization can be switched by an interlayer sliding, known as sliding ferroelectricity, which is advantageous in ultra-thin thickness, high switching speed, and high fatigue resistance. However, uncovering the relationship between the sliding path and the polarization state in rhombohedral-stacked materials remains a challenge, which is the key to 2D sliding ferroelectricity. Here, layer-dependent multidirectional sliding ferroelectricity in rhombohedral-stacked InSe (γ-InSe) is reported via dual-frequency resonance tracking piezoresponse force microscopy and conductive atomic force microscopy.
View Article and Find Full Text PDFAdv Mater
December 2024
Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, Shaanxi Key Laboratory for Advanced Energy Devices, School of Materials Science and Engineering, Shaanxi Normal University, Xi'an, 710119, P. R. China.
Chromium oxychloride (CrOCl), a van der Waals antiferromagnetic insulator, has attracted significant interest in 2D optoelectronic, ferromagnetic, and quantum devices. However, the bottom-up preparation of 2D CrOCl remains challenging, limiting its property exploration and device application. Herein, the controllable synthesis of 2D CrOCl crystals by chemical vapor deposition is demonstrated.
View Article and Find Full Text PDFJ Phys Condens Matter
December 2024
Department of Electrical Engineering and Department of Physics, National Central University, Chungli 32001, Taiwan.
Small Methods
November 2024
Key Laboratory of Polar Materials and Devices (MOE), Shanghai Center of Brain-inspired Intelligent Materials and Devices, School of Physics and Electronic Science, East China Normal University, Shanghai, 200241, China.
The polymorphic nature of InSe leads to excellent phase-dependent physical properties including ferroelectricity, photoelectricity, and especially the intriguing phase change ability, making the precise phase modulation of InSe of fundamental importance but very challenging. Here, the growth of InSe with desired-phase is realized by temperature-controlled selenization of van der Waals (vdW) layered bulk γ-InSe. Detailed results of Raman spectroscopy, scanning electron microscopy (SEM), and state-of-the-art spherical aberration-corrected transmission electron microscopy (Cs-TEM) clearly and consistently show that β-InSe, 3R α-InSe, and 2H α-InSe can be perfectly obtained at ≈270, ≈300, and ≈600 °C, respectively.
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