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Formation, Charge Transfer, Structural and Morphological Characteristics of ZnO Fractal-Percolation Nanosystems
摘要： Structural and morphological characteristics of ZnO nanosystems in the form of three-dimensional network-like systems have been investigated. Current–voltage (I–V) characteristics and charge transfer parameters of ZnO fractal-percolation nanosystems have been studied both in air and in vacuum at different temperatures and voltage sweep rates. The charge transfer characteristics show the presence of RaCiCai chains in the nanosystems. The RC chains are formed because the Debye screening length has the same order of magnitude as the local values of ZnO nanowires radii. Gas-sensing tests based on I–V characteristics investigation have shown a possibility of distinguishing between reducing gases such as CH4 or C2H5OH.
关键词： current–voltage characteristics,gas sensor,ZnO nanowires,charge transfer,reducing gas
更新于2025-09-19 17:15:36
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Optical properties of GaN Nanowires grown on chemical vapor deposited-Graphene
摘要： Optical properties of GaN nanowires grown on chemical vapor deposited graphene transferred on an amorphous support are reported. The growth temperature was optimized to achieve a high nanowire density with a perfect selectivity with respect to a SiO2 surface. The growth temperature window was found to be rather narrow (815 ± 5) °C. Steady-state and time-resolved photoluminescence from GaN nanowires grown on graphene was compared with the results for GaN nanowires grown on conventional substrates within the same molecular beam epitaxy (MBE) reactor showing a comparable optical quality for different substrates. Growth at temperatures above 820°C led to a strong NW density reduction accompanied with a diameter narrowing. This morphology change leads to a spectral blueshift of the donor bound exciton emission line due to either surface stress or dielectric confinement. Graphene multi-layered micro-domains were explored as a way to arrange GaN nanowires in a hollow hexagonal pattern. The nanowires grown on these domains show a luminescence spectral linewidth as low as 0.28 meV (close to the set-up resolution limit).
关键词： van der Waals epitaxy,photoluminescence,nanowires,GaN growth on graphene,graphene micro-domains
更新于2025-09-19 17:15:36
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Solution-Processed Anatase Titania Nanowires: From Hyperbranched Design to Optoelectronic Applications
摘要： The utilization of solar energy and the development of its related optoelectronic devices have become more important than ever. Solar cells or photoelectrochemical (PEC) cells that require the design of light harvesting assemblies for efficiently converting solar light into electricity or solar fuels are of particular interest. Semiconductor TiO2, serving as the photoelectrode for photovoltaic devices (e.g., dye- or quantum dot-sensitized solar cells (DSSCs/QDSSCs) or perovskite solar cells (PSCs)) and PEC cells, has aroused intense research interest owing to its inherent characteristics of wide band gap and promising optical and electrical properties. TiO2 nanowires (TNWs) have been widely used in optoelectronic devices due to their unique 1D geometry and salient optical and electrical properties. However, the insufficient surface area resulting from the relatively large diameter of NWs and considerable free space between adjacent NWs restricts their optoelectronic performance. Hence, it is desirable to explore every feasible aspect of TNWs in terms of structural design and optical management, aiming to further improve the performance of optoelectronic devices. In this Account, we present a brief survey of strategies for designing branched or hyperbranched TNW-based photoelectrodes and their applications in solar cells and PEC cells. The general strategies (e.g., alkaline/acid hydrothermal method, lift-off transfer, and self-assembly approach) are discussed to address the challenges associated with fabricating TNWs on transparent conducting oxide (TCO) substrates. A series of strategies to fabricate judiciously designed 3D branched array architectures, including length tuning and sequential surface branched or hyperbranched modification, are proposed. The versatile implantation of the TNWs onto other backbones (nanosheets, nanotubes, hollow spheres, or multilayered electrodes) and substrates (fiber-shaped metal wire or mesh, flexible metal foil, or plastic sheet) is demonstrated to construct a new class of the TNW-embedded composite electrode materials with desired morphological characteristics and optoelectronic properties, for example, favorable energy level alignment for cascade charge transfer and rational homogeneous/heterogeneous interfacial engineering. The functionalities of TNW-based electrodes include enlarged surface area and superior light scattering for maximized light harvesting, as well as facilitated charge transport and suppressed charge recombination for enhanced charge collection, which are promising in optoelectronic fields such as solar cells, photocatalysis, and PEC cells. Beyond TNWs, one can also integrate other types of semiconductor (e.g., Fe2O3 or WO3) NWs into rationally designed structures for preparing novel photocatalytic materials with panchromatic absorption, efficient charge transfer, and excellent catalytic properties. Finally, an insightful perspective for rational design of advanced NW-based materials is provided.
关键词： Solar cells,Hyperbranched design,Anatase titania nanowires,Photoelectrochemical cells,Optoelectronic applications,Solution-processed
更新于2025-09-19 17:15:36
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Electrospun CuS/PVP Nanowires and Superior Near-Infrared Filtration Efficiency for Thermal Shielding Applications
摘要： Selective filtration of near-infrared (NIR) region is of primary importance to energy saving via thermal shielding. However, uniform coating of highly effective nanomaterials on flexible substrates remains very challenging. Here, we introduce new materials processing and fabrication methodologies that manufacture electrospun copper sulfide/polyvinylpyrrolidone (CuS/PVP) nanowires for enhanced thermal shielding efficiency. Electrospinning offers well-dispersed CuS nanoparticles in a thermal shielding film, which is not achievable in typical solution coating processes. Directly deposited CuS/PVP nanowires on a flexible polymer membrane are enabled by a fluorination treatment that decreases interfacial electrostatic repulsion. Monitoring of in-situ temperature change of a box shielded, CuS/PVP nanowire film demonstrates excellent NIR shielding efficiency (87.15%). Direct integration of the film with a model car and exposure to direct sunlight demonstrates about twice-higher shielding efficiency than commercial tungsten-oxide films. Overall, the comprehensive study of nanomaterial preparation, surface treatment, and integration techniques allows to fabricate highly flexible and reliable thermal shielding films.
关键词： Near-infrared filtration,CuS/PVP nanowires,Thermal shielding,Electrospinning,and Flexible film
更新于2025-09-19 17:15:36
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Radial Nanowire Assemblies under Rotating Magnetic Field Enabled Efficient Charge Separation
摘要： Developing efficient charge separation strategies is essential to achieve high power conversion efficiency in fields of chemistry, biology and material science. Herein, we develop a facile strategy for fabrication of unique wafer-scale radial nanowire assemblies by exploiting shear force in rotary solution. The assembling mechanism can be well revealed by the large-scale stochastic dynamics simulation. Free electrons can be rapidly generated to produce quantitatively tunable current output when the radial nanowire assemblies rotating under the magnetic field. Moreover, the photoconductive performance of the radial semiconductor nanowire assemblies can be remarkably enhanced as the electron-hole recombination was retrained by the efficient charge separation under the rotating magnetic field. Such large-scale unique nanowire assemblies will facilitate the design of efficient charge separation process in bio-system, sensors and photocatalysis.
关键词： nanowires,charge separation,stochastic dynamics simulation,assembly,magnetic field
更新于2025-09-19 17:13:59
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A New Fabrication Method for Serpentine-Folded Waveguide Slow Wave Structure at W-Band
摘要： Thermionic energy converter (TEC) is a heat engine that generates electricity directly using heat as its source of energy and electron as its working fluid. Despite having a huge potential as an efficient direct energy conversion device, the progress in vacuum-based thermionic energy converter development has always been hindered by the space charge problem and the unavailability of materials with low work function. It is only recently that researchers have started to look back into this technology as recent advances in manufacturing technology techniques have made it possible to solve these problems, making TECs a viable option in replacing current energy production systems. The focus of this paper is to review the challenges of producing efficient and practical TECs, along with recent findings and developments in mitigating these challenges. Furthermore, this paper looked into potential applications of TECs, based on recent works and technologies, and found that, with certain improvements, it can be applied in many sectors.
关键词： nanowires,work function,thermionic energy conversion (TEC),space charge,Energy conversion efficiency
更新于2025-09-19 17:13:59
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Plasmonic gold sensitization of ZnO nanowires for solar water splitting
摘要： This paper reports the synthesis of plasmonic gold sensitized ZnO nanowires by chemical vapor deposition and subsequent photoreduction method. The well sensitization of Au nanoparticles with mean diameter of 5.3 nm on ZnO nanowires yield a higher photocurrent density of 1.06 mAcm-2 under illumination. Accordingly, Au nanoparticles on ZnO nanowires reveals the maximum photoelectrochemical water splitting efficiency of 0.45% at + 0.8 VRHE, which is higher than the ZnO nanowires (0.22% at + 0.8 VRHE). The enhanced photocurrent density and efficiency is due to the effective charge separation and transportation originating from metal support interaction, 1D nanostructure as well as surface plasmon resonance effect of Au nanoparticles.
关键词： Interfaces,Photoelectrochemical water splitting,Chemical vapor deposition,ZnO nanowires,Au nanoparticles
更新于2025-09-19 17:13:59
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Self-assembled template-confined growth of ultrathin CsPbBr3 nanowires
摘要： Fabrication of ultrathin (e.g., ～2 nm) CsPbBr3 nanowires is still challenging for existing methods, for the extremely fast crystal growth process of CsPbBr3. Here, we developed a self-assembled nanotemplate-confined growth concept to prepare ultrathin CsPbBr3 nanowires. During electrospinning using the N,N-dimethylformamide (DMF) solution composed of polymethyl methacrylate (PMMA), PbBr2, CsBr, and capping agents, PMMA chains would assemble into nanochannels acting as nanotemplates within the electrospun PMMA fibers. Owing to the very limited amount of precursors within the nanochannels, ultrathin CsPbBr3 nanowires were prepared after DMF evaporation. The CsPbBr3 nanowires within the PMMA fibers or dispersed in toluene showed bright blue luminescence. The structure of the CsPbBr3 products could be adjusted by the stirring time, as well as the amount of PMMA, PbBr2, and CsBr in DMF. Overall, we developed a new method towards engineering ultrafine CsPbBr3 nanostructure through self-assembled template-confined growth concept during electrospinning, which may find potential applications in blue light emitting diodes and other optoelectronic devices.
关键词： Nanowires,CsPbBr3,Electrospinning,Photoluminescence
更新于2025-09-19 17:13:59
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Enhanced Emission of Deep Ultraviolet Light-Emitting Diodes Through Using Work Function Tunable Cu Nanowires as Top Transparent Electrode
摘要： Deep ultraviolet light-emitting diodes (DUV LEDs) (< 280 nm) have been important light sources for broad applications in, e.g., sterilization, purification, high-density storage and etc. However, the lack of excellent transparent electrodes in DUV region remains a challenging issue. Here, we demonstrate an architectural engineering scheme to flexibly tune the work function of Cu@shell nanowires (NWs) as top transparent electrodes in DUV LEDs. By fast encapsulation of shell metals on Cu NWs and shift of electron binding energy, the electronic work function could be widely tailored down to 4.37 eV and up to 5.73 eV. It is revealed that the high work function of Cu@Ni and Cu@Pt NWs could overcome the interfacial barrier to p-AlGaN and achieve direct ohmic contact with high transparency (91%) in 200 ~ 400 nm. Completely transparent DUV LED chips are fabricated and successfully lighted with sharp top emission (wall-plug efficiency reaches 3 %) under a turn-on voltage of 6.4 V. This architectural strategy is of importance in providing highly transparent ohmic electrodes for optoelectronic devices in broad wavelength regions.
关键词： copper nanowires,transparent electrodes,light-emitting diodes,Deep ultraviolet,work function
更新于2025-09-19 17:13:59
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Interface engineering on ZnO/Au based Schottky junction for enhanced photoresponse of UV detector with TiO2 inserting layer
摘要： Metal-oxide semiconductor ZnO shows enormous potential in the field of photoelectric detection. However, the adsorption of H2O/O2 on its surface unavoidably results in degradation in the photo-response. Herein, AueTiO2eZnO (ATZ) ultraviolet (UV) photodetectors were designed to benefit the photosensing performance by weaken the surface state effect through tuning the Schottky junction interface with TiO2 insertion layer. As expect, 97% enhancement of IPh response together with three orders of magnitude decrease of dark current was triggered. This enhancement is owing to the efficiently separation and extraction of photoexcites under the effect of the stronger and expanding built-in field, which is a result of reduction of space charge density in barrier region induced by inhibiting H2O/O2 adsorption at the ZnO/Au interface. These findings here provide a promising method to boost performances of optoelectronic devices by interface engineering and could be extended to other semiconductor devices.
关键词： Zinc nanowires,Interface engineering,Surface states,Photodetector
更新于2025-09-19 17:13:59