All‐inorganic lead halide perovskite quantum dots (IHP QDs) have great potentials in photodetectors. However, the photoresponsivity is limited by the low charge transport efficiency of the IHP QD ...layers. High‐performance phototransistors based on IHP QDs hybridized with organic semiconductors (OSCs) are developed. The smooth surface of IHP QD layers ensures ordered packing of the OSC molecules above them. The OSCs significantly improve the transportation of the photoexcited charges, and the gate effect of the transistor structure significantly enhances the photoresponsivity while simultaneously maintaining high Iphoto/Idark ratio. The devices exhibit outstanding optoelectronic properties in terms of photoresponsivity (1.7 × 104 A W−1), detectivity (2.0 × 1014 Jones), external quantum efficiency (67000%), Iphoto/Idark ratio (8.1 × 104), and stability (100 d in air). The overall performances of our devices are superior to state‐of‐the‐art IHP photodetectors. The strategy utilized here is general and can be easily applied to many other perovskite photodetectors.
High‐performance hybrid phototransistors based on all‐inorganic lead halide perovskite quantum dots and organic semiconductors are fabricated and characterized. Because of the outstanding properties of the materials, the gate‐tunable phototransistors exhibit significantly high performance, including photoresponsivity (≈1.7 × 104 A W−1), detectivity (≈2.0 × 1014 Jones), EQE (≈67000%), Iphoto/Idark ratio (≈8.1 × 104), and long‐term stability in air.
Monolayer VSe2, featuring both charge density wave and magnetism phenomena, represents a unique van der Waals magnet in the family of metallic 2D transition‐metal dichalcogenides (2D‐TMDs). Herein, ...by means of in situ microscopy and spectroscopic techniques, including scanning tunneling microscopy/spectroscopy, synchrotron X‐ray and angle‐resolved photoemission, and X‐ray absorption, direct spectroscopic signatures are established, that identify the metallic 1T‐phase and vanadium 3d1 electronic configuration in monolayer VSe2 grown on graphite by molecular‐beam epitaxy. Element‐specific X‐ray magnetic circular dichroism, complemented with magnetic susceptibility measurements, further reveals monolayer VSe2 as a frustrated magnet, with its spins exhibiting subtle correlations, albeit in the absence of a long‐range magnetic order down to 2 K and up to a 7 T magnetic field. This observation is attributed to the relative stability of the ferromagnetic and antiferromagnetic ground states, arising from its atomic‐scale structural features, such as rotational disorders and edges. The results of this study extend the current understanding of metallic 2D‐TMDs in the search for exotic low‐dimensional quantum phenomena, and stimulate further theoretical and experimental studies on van der Waals monolayer magnets.
Monolayer VSe2 represents a unique system for exploring the interplay between charge density wave and magnetism phenomena. Evidence of spin frustration is obtained in monolayer VSe2, which is significant toward the search for exotic low‐dimensional quantum phases and further theoretical and experimental studies of van der Waals monolayer magnets.
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•A novel Co-MOF/Cu2O hybrid composite (xCMC) with p-n heterojunction was achieved.•The composite exhibited enhanced photocatalytic reduction of CO2 with superior selectivity to CO at ...the gas-solid interface.•The strong light absorption capacity, high surface area and p-n heterojunction enhanced the photocatalytic performance.•The reduction of CO2 was carried out without any photosensitizer, and sacrificing reagent.
It is highly desirable to discover MOFs matrix composites with controlled reduction selectivity in the general understanding of the CO2 reduction reaction (CO2RR) in electro- and photocatalytic process. Herein, we demonstrate a facile strategy to prepare metal organic framework hybrid composites (xCMC) using the Co-based MOF Co2(TMTA)(HCOO)(bidb)(H2O)∙DMF (H3TMTA = 1,3,5-trimethyl-2,4,6- tricarboxyl- phenylbenzene, bidb = 1,4-bis(1-imidazoly)benzene) and nanocrystalline cuprous oxide. The resulting hybrid catalyst with p-n heterojunction exhibited enhanced photocatalytic CO2 reduction activity with remarkable CO production rate of 3.83 μmol g−1h−1, ca. 9.6 times higher than that of pure Cu2O. Compared with other reaction routes, the present photocatalytic reduction of CO2 with superior selectivity to CO occurs in the interface of solid–gas reaction without the use of photosensitizers or sacrificing reagents. In addition, the mechanism for photocatalytic CO2 reduction was also well discussed. The present work provides unique insight into constructing MOF-based photocatalysts with heterojunction for visible-light-driven CO2 reduction under solid–gas reaction conditions.
An outbreak of the 2019 novel coronavirus (COVID-19) has been ongoing in China since January 2020. The threat of infection affects the work and life of most of the population and may also damage ...sleep. This study aims to examine the subjective sleep status and mental health of the population during the peak of the COVID-19 epidemic.
The data were collected through an online questionnaire with a sample of 5461 individuals in China from February 5, 2020, to February 23, 2020. Participants were divided into four groups based on their degree of threat from COVID-19: Group 1 was most closely associated with COVID-19, including inpatients diagnosed with COVID-19, first-line hospital workers and first-line management staff; Group 2 included outpatients diagnosed with COVID-19 and patients who developed a fever and visited the hospital; Group 3 included people related to Group 1 or 2, such as their colleagues, relatives, friends and rescuers; and Group 4 was the farthest removed from contact with COVID-19, covering the general public affected by COVID-19 prevention strategies. The Insomnia Severity Index (ISI), Patient Health Questionnaire (PHQ-9), Generalized Anxiety Disorder Scale (GAD-7) and Acute Stress Disorder Scale (ASDS) were used.
Threat degree of COVID-19 (groups) had significant correlations with insomnia, depression, anxiety, and stress (p < 0.05, p < 0.01). Age, gender, and area (Hubei province or other provinces) had significant correlations with insomnia (p < 0.01). A total of 1380 (24.46%) participants were suspected of having major depression based on the PHQ-9. Additionally, 1042 (18.47%) participants were suspected of having generalized anxiety disorder based on the GAD-7. A total of 892 (15.8%) of the participants had Acute Stress Disorder (ASD) according to the ASDS. The prevalence of clinical insomnia during the outbreak was 20.05% (1131) according to the ISI. The factors of satisfaction with the current sleep pattern and how perceptible the symptoms of the current sleep pattern are to other people (p < 0.05) and the middle (difficulty staying asleep) and terminal (waking up too early) (p < 0.01) factors of the ISI were significantly different across groups. A total of 1129 (20.01%) participants spent more than one hour awake in bed.
The results indicated that insomnia is more severe in people who are female, young, living in the epicenter and experiencing a high degree of threat from COVID-19. As prevention and treatment efforts continue with regard to COVID-19, the general public has developed poor sleep hygiene habits, which deserve attention.
•It reported the immediate impact of sleep status of a large sample at the peak of the COVID-19 spread in China.•Reports on sleep habits of individuals in China by different degrees of COVID-19 threat.•The threat degree of COVID-19 is associated with the prevalence of anxiety, depression and acute stress disorder.•The general public has developed poor sleep hygiene habits which deserve attention.
Climate change and public health are two interconnected societal challenges. Curbing fossil-based electricity generation reduces the emissions of both CO2 and air pollutants, which brings tangible ...health benefits from improved air quality. The potential health benefits from decarbonizing the grid are enormous, immediate, and widespread. From renewable portfolio standards to carbon market, the health co-benefits from clean electricity policies often outweigh their policy costs. As climate action goes local, framing decarbonization around health benefits also makes it more personally relevant and economically attractive. Yet, to date, the health impacts have largely been viewed as ancillary benefits from decarbonization, rather than as a core consideration when energy strategies are formed, assessed and implemented. When strategic choices are made about retiring old infrastructure and building new ones, bringing public health to the center of the discussion can generate greater health benefits with more equitable distribution. Here we identify concrete ways to incorporate air quality and health considerations into power sector decarbonization strategies. We draw insights mainly from empirical and modeling evidence for the United States. These insights are generally applicable and could guide health-oriented decarbonization efforts in other countries as well.
As companies and organizations have grown to rely on their computer systems and networks, the issue of information security management has become more significant. To maintain their competitiveness, ...enterprises should safeguard their information and try to eliminate the risk of information being compromised or reduce this risk to an acceptable level. This paper proposes an information security risk-control assessment model that could improve information security for these companies and organizations. We propose an MCDM model combining VIKOR, DEMATEL, and ANP to solve the problem of conflicting criteria that show dependence and feedback. In addition, an empirical application of evaluating the risk controls is used to illustrate the proposed method. The results show that our proposed method can be effective in helping IT managers validate the effectiveness of their risk controls.
Graphitic carbon nitride (g-C3N4) has attracted worldwide attention, because of its promising potential applications and theoretical prediction of its unique properties. Herein, 1-, 2- and 4-layer ...g-C3N4 nanosheets were synthesized in a well-crystallized form by controlling the intercalation time in a simple intercalation–exfoliation process. The electronic structures of the nanosheets were captured in their Raman spectra that clearly evolved with the layer number of the nanosheets for the first time. A clear correlation between the spectral properties and the layer number of the nanosheets was clarified by combining Raman spectra and the first-principles calculations. Raman vibrational modes of g-C3N4 were assigned. The layer–layer deformation vibrations and related in-plane twisting vibrations or symmetrical stretching vibrations reflected the change in the electronic structure of the nanosheets with different layers. The results may shed light on brand-new opportunities for significant improvements in the synthesis, structure, electronic and optical properties of single-layer and ultrathin g-C3N4 nanosheets toward desirable functional materials.
Glioblastoma (GBM) is the most malignant and highly aggressive brain tumor. In this study, four types of typical GBM cell lines (LN229, SNB19, U87, U251) were cultured in a microfabricated 3-D model ...to study their in vitro behaviors. The 3-D in vitro model provides hollow micro-chamber arrays containing a natural collagen interface and thus allows the GBM cells to grow in the 3-D chambers. The GBM cells in this model showed specific properties on the aspects of cell morphology, proliferation, migration, and invasion, some of which were rarely observed before. Furthermore, how the cells invaded into the surrounding ECM and the corresponding specific invasion patterns were observed in details, implying that the four types of cells have different features during their development in cancer. This complex in vitro model, if applied to patient derived cells, possesses the potential of becoming a clinically relevant predictive model.
Simultaneous Localization and Mapping (SLAM) poses distinct challenges, especially in settings with variable elements, which demand the integration of multiple sensors to ensure robustness. This ...study addresses these issues by integrating advanced technologies like LiDAR-inertial odometry (LIO), visual-inertial odometry (VIO), and sophisticated Inertial Measurement Unit (IMU) preintegration methods. These integrations enhance the robustness and reliability of the SLAM process for precise mapping of complex environments. Additionally, incorporating an object-detection network aids in identifying and excluding transient objects such as pedestrians and vehicles, essential for maintaining the integrity and accuracy of environmental mapping. The object-detection network features a lightweight design and swift performance, enabling real-time analysis without significant resource utilization. Our approach focuses on harmoniously blending these techniques to yield superior mapping outcomes in complex scenarios. The effectiveness of our proposed methods is substantiated through experimental evaluation, demonstrating their capability to produce more reliable and precise maps in environments with variable elements. The results indicate improvements in autonomous navigation and mapping, providing a practical solution for SLAM in challenging and dynamic settings.
Ag electrode is widely used in inverted perovskite solar cells (PSCs), but its easy reaction and corrosive nature with perovskite always induces severe stability issue. Here, from typical theory of ...metal anticorrosion, a chemical anticorrosion approach for Ag electrode in inverted PSCs through introducing 2‐mercaptobenzothiazole (MBT) as a corrosion inhibitor is reported. MBT can strongly bond to Ag and form a compact MBT‐Ag chain on Ag surface owing to its N atom in thiazolyl ring and exocyclic thiol groups. As a result, Ag anticorrosion ability is greatly enhanced by increasing the corrosion potential and decreasing the corrosion current, thus effectively inhibiting possible chemical reaction and corrosion between perovskite and Ag electrodes. PSCs containing MBT/Ag exhibit high efficiency of over 23% with good stability, retaining 95 ± 4.1% of initial efficiency after storage for 3800 h in glovebox. Importantly, resulting PSCs also show excellent thermal stability, maintaining 90 ± 1.8% of initial efficiency after aging for 900 h at 85 °C.
A chemical anticorrosion strategy is proposed to inhibit Ag electrode corrosion in inverted perovskite solar cells through introducing 2‐mercaptobenzothiazole (MBT) inhibitor. MBT can bond on Ag surface to inhibit Ag corrosion. Resulting devices exhibit >23% efficiency with good stability, retaining >90% of initial efficiency whether after N2 storage for 3800 h or 85 °C aging for 900 h.
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