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A Predictive Model for the Electrical Transport Within Nanowire Networks
摘要: Thin networks of high aspect ratio conductive nanowires can combine high electrical conductivity with excellent optical transparency, which has led to a widespread use of nanowires in transparent electrodes, transistors, sensors, and ?exible and stretchable conductors. Although the material and application aspects of conductive nanowire ?lms have been thoroughly explored, there is still no model which can relate fundamental physical quantities, like wire resistance, contact resistance and nanowire density, to the sheet resistance of the ?lm. Here we derive an analytical model for the electrical conduction within nanowire networks based on an analysis of the parallel resistor network. The model captures the transport characteristics and ?ts a wide range of experimental data, allowing for the determination of physical parameters and performance limiting factors, in sharp contrast to the commonly employed percolation theory. The model thus constitutes a useful tool with predictive power for the evaluation and optimization of nanowire networks in various applications.
关键词: nanowires,electrical transport,model,percolation,carbon nanotubes,nanowire network,silver nanowires
更新于2025-09-23 15:21:01
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Piezo-phototronic effect enhanced polarization-sensitive photodetectors based on cation-mixed organica??inorganic perovskite nanowires
摘要: Piezo-phototronic effect has been extensively investigated for the third generation semiconductor nanowires. Here, we present a demonstration that piezo-phototronic effect can even be applied to tune polarization-sensitive photodetectors based on cation-mixed organic–inorganic perovskite nanowires. A big anisotropic photoluminescence (PL) with linearly polarized light-excitation was found due to a strong spontaneous piezoelectric polarization besides the anisotropic crystal structure and morphology. The piezo-phototronic effect was utilized to tune the PL intensity, and an improved anisotropic PL ratio from 9.36 to 10.21 for linearly polarized light-excitation was obtained thanks to the modulation by piezo-potential. And a circularly polarization-sensitive PL characterized with circular dichroism ratio was also discovered, which was found to be modulated from 0.085 to 0.555 (with a 5.5-fold improvement) within the range of applied strain. The circular dichroism was resulted from the joint effects of the modulated Rashba spin–orbit coupling and the asymmetric carriers separation and recombination for right- and left-handed helicity due to the presence of effective piezo-potential. These findings not only reveal the promising optoelectronic applications of piezo-phototronic effect in perovskite-based polarization-sensitive photodetectors, but also illuminate fundamental understandings of their polarization properties of perovskite nanowires.
关键词: polarization-sensitive photodetectors,perovskite nanowires,Rashba spin–orbit coupling,Piezo-phototronic effect,photoluminescence
更新于2025-09-23 15:21:01
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Surface Engineered Hybrid Corea??Shell Sia??Nanowires for Efficient and Stable Broadband Photodetectors
摘要: Silicon nanostructures have gained intensive interest to develop broadband photodetectors at a large-scale due to their excellent electronic properties. Herein, Si-nanowires (SiNWs) decorated with reduced graphene oxide:carbon quantum dots (rGO:CQDs) nanocomposite (NC), as core–shell heterojunction building blocks for broadband (ultraviolet (UV)–near infrared (NIR)) photodetectors (PDs), are demonstrated. The SiNWs and CQDs are synthesized by wet-chemical etching and facile pyrolysis methods, respectively. Photogenerated carriers are transported through rGO because of its high electron mobility and favorable band alignment with CQDs and Si. Further, to minimize the recombination of photogenerated carriers, and enhance the response in the visible region, plasmon-enhanced AuCQDs are incorporated in the shell matrix. The optimized heterostructure (rGO:AuCQDs/undoped CQDs/SiNWs) is sensitive to a broad wavelength range covering the UV to NIR (360 to 940 nm) region, manifests the excellent responsivity of 16 A W?1 at 360 nm, detectivity (D*) of 2.2 × 1013 Jones, and noise equivalent power as low as 2.8 fW Hz?1/2. The optimized PDs heterostructure demonstrates excellent air-stability after 8 days of illumination without any encapsulation or protective coating. The proposed simple, cost-effective, and Si-process-line compatible fabrication of Si-based PD device structure imposes a great promise for highly efficient and stable advanced futuristic optoelectronic devices.
关键词: core–shell heterostructure,detectivity,responsivity,broadband photodetectors,reduced graphene oxide,carbon quantum dots,Si nanowires
更新于2025-09-23 15:21:01
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Using a nanosecond laser to pattern copper nanowire-based flexible electrodes: From simulation to practical application
摘要: Copper nanowire (Cu NW) electrodes have shown promise for use in next-generation transparent conducting films due to their high electrical conductivity, low-cost solution-based synthesis processes, and high transmittance properties. Recently, the use of lasers for the modification of nanostructures has received considerable attention. Despite the advantages of laser machining such as producing any shape in an accurate, time-saving, non-contact process, the laser patterning of Cu NW electrodes has not been extensively studied, particularly the heat effect of the laser irradiation process on the flexible substrate. In this report, we present experimental and computational results of a selective and direct patterning process by using nanosecond pulsed laser irradiation. The experimental and simulation results were used to optimize the laser ablation parameters for the patterning process of the ultra-long Cu NW transparent electrodes so as to not damage the flexible substrates. Finally, a bifunctional flexible smart-window was fabricated to demonstrate a practical application of the laser-patterned Cu NW electrodes.
关键词: Copper nanowires,Laser patterning,Flexible substrate,Nanosecond pulsed laser,Flexible smart-window
更新于2025-09-23 15:21:01
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Ultra-long high quality catalyst-free WO<sub>3</sub> nanowires for fabricating high-performance visible photodetectors
摘要: This work presents a study on the controlled growth of WO3 nanowires via chemical vapor deposition without catalyst, and their potential applications in visible photodetectors. The influence of growth conditions on the morphology of WO3 nanowires is studied in order to understand the growth mechanism of WO3 nanowires, and ultra-long (60 μm, the longest one ever reported) WO3 nanowires with a spindle shape are achieved by optimizing the growth conditions. The photoconductor detectors based on WO3 single nanowires present excellent device performance with a responsivity as high as 19 A/W at a bias of 0.1 V, a detectivity as high as 1.06 × 1011 Jones, and a response (rising and decay) time as short as 8 ms under the illumination of a 404 nm laser. These results indicate the great potential of WO3 nanowires for applications in fabricating high performance visible photodetectors.
关键词: visible light,high performance,photodetectors,chemical vapor deposition,WO3 nanowires
更新于2025-09-23 15:21:01
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CsPbBr3 nanowire polarized light-emitting diodes through mechanical rubbing
摘要: Anisotropic films composed of aligned CsPbBr3 nanowires (NWs) have been successfully fabricated using a mechanical rubbing method. The films with dense and uniform morphology show polarization photoluminescence (PL) behavior. Combining with an optimal device structure, a polarized light-emitting diode (LED) with a turn-on voltage as low as 6.5 V was achieved.
关键词: CsPbBr3 nanowires,anisotropic films,mechanical rubbing,polarized light-emitting diode,photoluminescence
更新于2025-09-23 15:21:01
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Rational Interface Engineering for Efficient Flexible Perovskite Light-Emitting Diodes
摘要: Although perovskite light-emitting diodes (Pe-LEDs) are promising for next-generation displays and lighting, their efficiency is still considerably below that of conventional inorganic and organic counterparts. Significant efforts in various aspects of the electroluminescence process are required to achieve high-performance PeLEDs. Here, we present an improved flexible PeLED structure based on the rational interface engineering for energy-efficient photon generation and enhanced light outcoupling. The interface-stimulated crystallization and defect passivation of the perovskite emitter are synergistically realized by tuning the underlying interlayer, leading to the suppression of trap-mediated nonradiative recombination losses. Besides approaching highly emissive perovskite layers, the outcoupling of trapped light is also enhanced by combining the silver nanowires-based electrode with quasi-random nanopatterns on flexible plastic substrate. Upon the collective optimization of the device structure, a record external quantum efficiency of 24.5% is achieved for flexible PeLEDs based on green-emitting CsPbBr3 perovskite.
关键词: defect passivation,flexible perovskite light-emitting diodes,perovskite light-emitting diodes,silver nanowires,light outcoupling
更新于2025-09-23 15:21:01
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[Institution of Engineering and Technology 20th Italian National Conference on Photonic Technologies (Fotonica 2018) - Lecce, Italy (23-25 May 2018)] 20th Italian National Conference on Photonic Technologies (Fotonica 2018) - Second Harmonic Generation Circul Dichroism in Au Coated Gaas-based Nanowires
摘要: Nanostructures with broken symmetry can interact with circularly polarized light to mimic chiroptical (chiral-optical) effects, usually observable in chiral media. This phenomenon is known as extrinsic chirality. Second harmonic generation (SHG) is extremely sensitive to symmetry breaking, down to a single atomic monolayer and it has been extensively used as a probe of extrinsic chirality. Here we present SHG measurements of GaAs nanowires partially covered with Au, fabricated by a self-catalysed technique. The Au coated GaAs nanowires give rise to a dramatic circular dichroism in the generated second harmonic signal, compared to nanowires without coating.
关键词: plasmonic coating,extrinsic chirality,second harmonic generation,GaAs nanowires
更新于2025-09-23 15:21:01
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Plasmonics || Plasmonic Modes in Au and AuAg Nanowires and Nanowire Dimers Studied by Electron Energy Loss Spectroscopy
摘要: In this chapter, we review our recent work on the investigation of surface plasmon modes in metallic nanowires and nanowire dimers by means of electron energy loss spectroscopy combined with scanning transmission electron microscopy (STEM-EELS). Due to the very high spatial resolution, STEM-EELS is a powerful technique to visualize multipole order surface plasmon modes in nanowires and study the dependency of their resonance energies on different parameters such as nanowire dimensions or nanowire porosity. In addition, we investigate surface plasmon hybridization in nanowires separated by gaps of less than 10 nm or connected by small metallic bridges. In such structures new modes arise, which depend strongly on gap or bridge sizes. Experimental results are supported by finite element simulations. The investigated nanowires and dimers are fabricated by electrodeposition in etched ion-track templates, combined with a selective dissolution processes. The synthesis techniques and their advantages for the fabrication of plasmonic nanostructures are also discussed.
关键词: nanowire dimers,scanning transmission electron microscopy,ion-track technology,electron energy loss spectroscopy,nanogaps,nanowires,electrodeposition,plasmon hybridization,etched ion-track membranes,surface plasmons,gold
更新于2025-09-23 15:21:01
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Growth mechanisms of F4-TCNQ on inorganic substrates and nanostructures
摘要: The organic semiconductor tetrafluorotetracyanoquinodimethane (F4-TCNQ) is a promising candidate for the doping of organic semiconductors, two-dimensional materials and inorganic compounds, such as ZnO, and also to enhance the charge carrier injection at contacts in organic electronics. In order to evaluate its applicability as a functionalization material or as an electrically active part in devices, we present a systematic study on the growth mode of F4-TCNQ beyond the first few monolayers on different inorganic substrates that cover a broad variety regarding their physical, chemical and morphological surface properties. The materials used are silicon, silicon carbide, graphene on silicon, sapphire, nanocrystalline diamond, as well as gallium nitride (GaN) layers and nanowire arrays. While the surface termination influences the shape and morphology of the islands of F4-TCNQ which form on all substrates investigated, no significant dependence of the growth mode on the substrate doping type and concentration is observed. GaN nanowires are found to act as nucleation sites for F4-TCNQ islands and to be covered by few monolayers of F4-TCNQ forming a closed coaxial shell. In conclusion, F4-TCNQ is identified to nucleate via Stranski-Krastanov growth consisting of monolayers and islands of different size and shape. The findings in this work provide basic growth information for the implementation of F4-TCNQ as functionalization material for nanowire-based applications.
关键词: GaN nanowires,surface functionalization,growth mode,organic semiconductors,organic electronics,surface doping,F4-TCNQ
更新于2025-09-23 15:21:01