Recent years have witnessed the rise of graphene and its applications in various electronic devices. Specifically, featuring excellent flexibility, transparency, conductivity, and mechanical ...robustness, graphene has emerged as a versatile material for flexible electronics. In the past decade, facilitated by various laser processing technologies, including the laser‐treatment‐induced photoreduction of graphene oxides, flexible patterning, hierarchical structuring, heteroatom doping, controllable thinning, etching, and shock of graphene, along with laser‐induced graphene on polyimide, graphene has found broad applications in a wide range of electronic devices, such as power generators, supercapacitors, optoelectronic devices, sensors, and actuators. Here, the recent advancements in the laser fabrication of graphene‐based flexible electronic devices are comprehensively summarized. The various laser fabrication technologies that have been employed for the preparation, processing, and modification of graphene and its derivatives are reviewed. A thorough overview of typical laser‐enabled flexible electronic devices that are based on various graphene sources is presented. With the rapid progress that has been made in the research on graphene preparation methodologies and laser micronanofabrication technologies, graphene‐based electronics may soon undergo fast development.
Recent advancements in the laser fabrication of graphene‐based flexible electronic devices are comprehensively reviewed. Various laser processing technologies that enable preparation, processing, and modification of graphene and its derivatives are summarized. An overview of typical laser‐fabricated flexible electronic devices based on graphene‐related materials is presented.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In this paper, we focus on tackling the problem of automatic accurate localization of detected objects in high-resolution remote sensing images. The two major problems for object localization in ...remote sensing images caused by the complex context information such images contain are achieving generalizability of the features used to describe objects and achieving accurate object locations. To address these challenges, we propose a new object localization framework, which can be divided into three processes: region proposal, classification, and accurate object localization process. First, a region proposal method is used to generate candidate regions with the aim of detecting all objects of interest within these images. Then, generic image features from a local image corresponding to each region proposal are extracted by a combination model of 2-D reduction convolutional neural networks (CNNs). Finally, to improve the location accuracy, we propose an unsupervised score-based bounding box regression (USB-BBR) algorithm, combined with a nonmaximum suppression algorithm to optimize the bounding boxes of regions that detected as objects. Experiments show that the dimension-reduction model performs better than the retrained and fine-tuned models and the detection precision of the combined CNN model is much higher than that of any single model. Also our proposed USB-BBR algorithm can more accurately locate objects within an image. Compared with traditional features extraction methods, such as elliptic Fourier transform-based histogram of oriented gradients and local binary pattern histogram Fourier, our proposed localization framework shows robustness when dealing with different complex backgrounds.
The electronic structure of transition metal complexes can be modulated by replacing partial ion of complexes to obtain tuned intrinsic oxygen reduction reaction (ORR) or oxygen evolution reaction ...(OER) electrocatalytic activity. However, the anion‐modulated transition metal complexes ORR activity of is still unsatisfactory, and the construction of hetero‐anionic structure remains challenging. Herein, an atomic doping strategy is presented to prepare the CuCo2O4‐xSx/NC‐2 (CCSO/NC‐2) as electrocatalysts, the structrual characterization results favorably demonstrate the partial substitution of S atoms for O in CCSO/NC‐2, which shows excellent catalytic performance and durability for OER and ORR in 0.1 m KOH. In addition, the catalyst assembled Zinc–air battery with an open circuit potential of 1.43 V maintains performance after 300 h of cyclic stability. Theoretical calculations and differential charges illustrate that S doping optimizes the reaction kinetics and promotes electron redistribution. The superior performance of CCSO/NC‐2 catalysis is mainly due to its unique S modulation of the electronic structure of the main body. The introduction of S promotes CoO covalency and constructs a fast electron transport channel, thus optimizing the adsorption degree of active site Co to the reaction intermediates.
To investigate the bifunctional performance of hetero‐anionic structure for oxygen electrocatalysis, CuCo2O4‐xSx/NC‐2 catalysts are constructed and afford excellent catalytic performance in oxygen reduction reaction (ORR) or oxygen evolution reaction (OER). The superior performance of the CuCo2O4‐xSx/NC‐2 catalysts is attributed to the unique S modulation of the main body electronic structure, CoS bond provides fast electron transport channel, thus optimizing the adsorption degree of active site Co to the reaction intermediates.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Atomic substitutions at the tetrahedral site (ATd) could theoretically achieve an efficient optimization of the charge at the octahedral site (BOh) through the ATd‐O‐BOh interactions in the spinel ...oxides (AB2O4). Despite substantial progress having been made, the precise control and adjustment of the spinel oxides are still challenging owing to the complexity of their crystal structure. In this work, we demonstrate a simple solvent method to tailor the structures of spinel oxides and use the spinel oxide composites (ACo2O4/NCNTs, A=Mn, Co, Ni, Cu, Zn) for oxygen electrocatalysis. The optimized MnCo2O4/NCNTs exhibit high activity and excellent durability for oxygen reduction/evolution reactions. Remarkably, the rechargeable liquid Zn–air battery equipped with a MnCo2O4/NCNTs cathode affords a specific capacity of 827 mAh gZn−1 with a high power density of 74.63 mW cm−2 and no voltage degradation after 300 cycles at a high charging–discharging rate (5 mA cm−2). The density functional theory (DFT) calculations reveal that the substitution could regulate the ratio of Co3+/Co2+ and thereby lead to the modulation of the electronic structure accompanied with the movement of the d‐band center. The tetrahedral and octahedral sites interact through the Mn−O−Co, and the Co3+Oh of MnCo2O4 with the optimal charge structure allows a more suitable binding interaction between the active center and the oxygenated species, resulting in superior oxygen electrocatalytic performance.
A series of Co‐based spinel oxides coupled with N‐doped carbon nanotubes were synthesized as electrocatalysts for the oxygen reduction/evolution reaction. The cation‐tuning induced ATd‐O‐BOh corner‐sharing effect enables the modulation and optimization of the electronic structure of Co‐based spinel oxides, resulting in the superior electrocatalytic activity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
An active absorption device is proposed based on vanadium dioxide metamaterials. By controlling the conductivity of vanadium dioxide, resonant absorbers are designed to work at wide range of ...terahertz frequencies. Numerical results show that a broadband terahertz absorber with nearly 100% absorptance can be achieved, and its normalized bandwidth of 90% absorptance is 60% under normal incidence for both transverse-electric and transverse-magnetic polarizations when the conductivity of vanadium dioxide is equal to 2000 Ω
cm
. Absorptance at peak frequencies can be continuously tuned from 30% to 100% by changing the conductivity from 10 Ω
cm
to 2000 Ω
cm
. Absorptance spectra analysis shows a clear independence of polarization and incident angle. The presented results may have tunable spectral applications in sensor, detector, and thermophotovoltaic device working at terahertz frequency bands.
Developing highly active, non-noble-metal H2 evolution co-catalysts is appealing yet still remains a great challenge in the promising field of visible-light-driven photocatalytic solar fuel H2 ...production. In this work, high quality hexagonal Ni3C nanoparticles were facilely fabricated through the low-temperature thermolysis of nickel acetylacetonate in oleylamine under a nitrogen atmosphere and were then coupled with g-C3N4 by a simple grinding method. The photocatalytic performances of g-C3N4/Ni3C nanoheterojunctions were tested under visible light irradiation using triethanolamine (TEOA) as a hole scavenger. The optimal H2-production rate of 15.18 μmol h−1 over 15 wt% Ni3C nanoparticle decorated g-C3N4, corresponding to an apparent quantum yield (AQY) of 0.40% at 420 nm, is approximately 116.7 times higher than that of pure g-C3N4 and is even larger than that of the 0.5 wt% Pt/g-C3N4 sample. Well resolved density functional theory (DFT) calculation reveals that the “TOP” site of Ni3C(113) with a H adsorption energy of −0.97 eV is likely the dominant reaction site for H2 evolution, rather than the Hollow and Bridge sites. It was also demonstrated by the polarization curves that the Ni3C nanoparticles could act as multi-functional electrocatalysts to improve the kinetics for water oxidation, the oxidation of TEOA, and hydrogen evolution in both acidic and basic media. Therefore, the loading of multi-functional Ni3C cocatalyst nanoparticles onto g-C3N4 can fundamentally promote the rapid transportation/separation of charge carriers, enhance the oxidation kinetics of TEOA, and decrease the overpotential of H2-evolution, thus favoring significantly enhanced photocatalytic activity. It is highly expected that this work will provide new ideas to develop robust metal carbides as noble-metal-free cocatalysts for high-efficiency and low-cost g-C3N4-based photocatalytic water splitting.
This paper contributes to the literature by identifying the causal effect of firm investment on exporting behavior. The identification hinges on regional variations in the 2004 value-added tax pilot ...reform in China, which generated positive investment shocks. The instrumental variable estimation results show that firm investment significantly and substantially increases the likelihood of exporting, and this effect is largely due to the positive effect of firm investment on firm productivity. Finally, the paper documents some heterogeneity of the effect across industries with different degrees of competition and financial constraints.
•We identify the causal effect of firms' fixed investment on their exporting behavior with the Difference-in-Differences method.•Our results show that fixed investment significantly and substantially increases the likelihood of exporting.•We document some heterogeneity of the effect across industries with different degrees of competition and financial constraints.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Interface strains and lattice distortion are inevitable issues during perovskite crystallization. Silane as a coupling agent is a popular connector to enhance the compatibility between inorganic and ...organic materials in semiconductor devices. Herein, a protonated amine silane coupling agent (PASCA‐Br) interlayer between TiO2 and perovskite layers is adopted to directionally grasp both of them by forming the structural component of a lattice unit. The pillowy alkyl ammonium bromide terminals at the upper side of the interlayer provide well‐matched growth sites for the perovskite, leading to mitigated interface strain and ensuing lattice distortion; meanwhile, its superior chemical compatibility presents an ideal effect on healing the under‐coordinated Pb atoms and halogen vacancies of bare perovskite crystals. The PASCA‐Br interlayer also serves as a mechanical buffer layer, inducing less cracked perovskite film when bending. The developed molecular‐level flexible interlayer provides a promising interfacial engineering for perovskite solar cells and their flexible application.
A protonated amino silane coupling agent as an interlayer is exploited on rigid and flexible substrates, which not only sets up well‐matched growth underlay but also serves as a structural component of the lattice units, leading to less‐distorted perovskite films, resulting in an obvious advance in device performance, stability, and mechanical tolerance in the corresponding flexible device.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Herein, we highlight redox‐inert Zn2+ in spinel‐type oxide (ZnXNi1−XCo2O4) to synergistically optimize physical pore structure and increase the formation of active species on the catalyst surface. ...The presence of Zn2+ segregation has been identified experimentally and theoretically under oxygen‐evolving condition, the newly formed VZn−O−Co allows more suitable binding interaction between the active center Co and the oxygenated species, resulting in superior ORR performance. Moreover, a liquid flow Zn–air battery is constituted employing the structurally optimized Zn0.4Ni0.6Co2O4 nanoparticles supported on N‐doped carbon nanotube (ZNCO/NCNTs) as an efficient air cathode, which presents remarkable power density (109.1 mW cm−2), high open circuit potential (1.48 V vs. Zn), excellent durability, and high‐rate performance. This finding could elucidate the experimentally observed enhancement in the ORR activity of ZnXNi1−XCo2O4 oxides after the OER test.
The outstanding electrocatalytic performance of Zn0.4Ni0.6Co2O4/NCNTs towards ORR/OER is validated, presenting remarkable rate capability and durability in liquid‐flow Zn–air batteries. A dual‐reinforcement mechanism in the Zn–Ni–Co ternary spinel is also proposed. Zn0.4Ni0.6Co2O4/NCNTs exhibits extreme durability and electrochemically enhanced properties, enabling its application in practical rechargeable zinc–air batteries.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Development of easy‐to‐make, highly active, and stable bifunctional electrocatalysts for water splitting is important for future renewable energy systems. Three‐dimension (3D) porous Ni/Ni8P3 and ...Ni/Ni9S8 electrodes are prepared by sequential treatment of commercial Ni‐foam with acid activation, followed by phosphorization or sulfurization. The resultant materials can act as self‐supported bifunctional electrocatalytic electrodes for direct water splitting with excellent activity toward oxygen evolution reaction and hydrogen evolution reaction in alkaline media. Stable performance can be maintained for at least 24 h, illustrating their versatile and practical nature for clean energy generation. Furthermore, an advanced water electrolyzer through exploiting Ni/Ni8P3 as both anode and cathode is fabricated, which requires a cell voltage of 1.61 V to deliver a 10 mA cm−2 water splitting current density in 1.0 m KOH solution. This performance is significantly better than that of the noble metal benchmark—integrated Ni/IrO2 and Ni/Pt–C electrodes. Therefore, these bifunctional electrodes have significant potential for realistic large‐scale production of hydrogen as a replacement clean fuel to polluting and limited fossil‐fuels.
Three‐dimension nickel‐based electrocatalytic electrodes (Ni/Ni8P3 and Ni/Ni9S8) are developed for application in water splitting. The as‐obtained Ni/Ni8P3 catalytic electrode, particularly exhibiting excellent electrocatalytic activity and stability due to its advanced structure effects, can serve as a highly efficient and stable bifunctional catalyst for overall water splitting.
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