Hybrid Nanowires Research Articles

Misfit strain induced out-of-interface prismatic dislocation loops in axially inhomogeneous hybrid nanowires

The possibility of forming the misfit-strain-induced out-of-interface prismatic dislocation loops (PDLs) in axially inhomogeneous hybrid two-phase nanowires with a transverse interface is theoretically studied. It is shown that, due to the misfit stresses caused by the contact of two crystalline materials with different lattice parameters, the PDLs of certain radii can generate at certain distances from the interface when the nanowire radius is larger than a critical value, which depends on the lattice misfit. The critical parameters of the relaxation process are calculated and discussed in detail.

Nonlocal measurement of quasiparticle charge and energy relaxation in proximitized semiconductor nanowires using quantum dots

The lowest-energy excitations of superconductors do not carry an electric charge, as their wave function is equally electron-like and hole-like. This fundamental property is not easy to study in electrical measurements that rely on the charge to generate an observable signal. The ability of a quantum dot to act as a charge filter enables us to solve this problem and measure the quasiparticle charge in superconducting-semiconducting hybrid nanowire heterostructures. We report measurements on a three-terminal circuit, in which an injection lead excites a non-equilibrium quasiparticle distribution in the hybrid system, and the electron or hole component of the resulting quasiparticles is detected using a quantum dot as a tunable charge and energy filter. The results verify the chargeless nature of the quasiparticles at the gap edge and reveal the complete relaxation of injected charge and energy in a proximitized nanowire, resolving open questions in previous three-terminal experiments.

Nanomolding of topological nanowires

For more than a decade since their experimental confirmation, topological materials have elicited interest from a wide variety of fields due to their unique symmetry-protected electronic states. Given a large number of theoretically predicted topological materials, new strategies are needed to fabricate topological nanomaterials in a high throughput manner in order to identify promising topological candidates for use in functional devices. In this Perspective, we discuss the use of nanomolding to fabricate topological nanowires; nanomolding is a scalable fabrication process in which a bulk polycrystalline feedstock is pressed into a nanostructured mold at an elevated temperature to form nanowires. Unlike traditional top-down and bottom-up fabrication methods, nanomolding requires minimal optimization of experimental parameters and can work on a wide variety of topological compounds, thus enabling high throughput fabrication of topological nanowires. The fabricated nanowires are single crystalline and defect-free and can have high aspect ratios greater than 1000. We also discuss how future developments in nanomolding can lead to new heterostructures, such as superconductor/semiconductor hybrid nanowires, and other nanomaterial shapes, such as plates or ribbons.

Strain energy in hybrid nanowire structures with axially varying eigenstrain

The strain energy states of nanowires (NWs) with axial variation in either chemical composition or temperature are considered. Such nonuniformities from the mechanical point of view are described as axially varying eigenstrain in the material interior. The nanodisk/nanowire (ND/NW) hybrid structures comprising of a single or a pair of interacting nonuniformities which can be also treated as dilatational inclusions (DIs) formed in a NW, are analysed. The cases of sharp (abrupt) and smooth (diffuse) variations of eigenstrain are compared. It is shown that the energy conditions dictate an increase in the length of the transition region between the NW parts of constant eigenstrain.

Synthesis of silver sulfide nanowires: Variation of the morphology and structure

The beaded string silver sulfide nanowires (Ag2S NWs) are produced by the sulfuration reaction between silver nanowires (Ag NWs) and sodium polysulfide (Na2Sx) within the aqueous solution at room temperature. The reaction was preferentially initiated at the tip and defect of the Ag NWs, and the volume expansion occurs at the sulfurized sites due to the larger volume of silver sulfide (Ag2S) than silver (Ag). As the reaction progresses, the sulfurized area spreads around, resulting in multiple protrusion of the Ag-Ag2S hybrid nanowires. The lag reaction position to be unable to embed enough sulfur atoms due to the extrusion stress of expansion on both sides, leading to the formation of the flat bamboo joint sandwiched between bulges finally. This paper describes the structure evolution and morphology transformation of Ag NWs during the sulfuration process, and focuses on the studying of sulfuration mechanism.

Flexible and Transparent Electrode of Hybrid Ti3C2TX MXene-Silver Nanowires for High-Performance Quantum Dot Light-Emitting Diodes.

The development of electrodes with high conductivity, optical transparency, and reliable mechanical flexibility and stability is important for numerous solution-processed photoelectronic applications. Although transparent Ti3C2TX MXene electrodes with high conductivity are promising, their suitability for displays remains limited because of the high sheet resistance, which is caused by undesirable flake junctions and surface roughness. Herein, a flexible and transparent electrode has been fabricated that is suitable for a full-solution-processed quantum dot light-emitting diode (QLED). An MXene-silver nanowire (AgNW) hybrid electrode (MXAg) consists of a highly conductive AgNW network mixed with solution-processed MXene flakes. Efficient welding of wire-to-wire junctions with MXene flakes yields an electrode with a low sheet resistance and a high transparency of approximately 13.9 Ω sq-1 and 83.8%, respectively. By employing a thin polymer buffer layer of poly(methyl methacrylate) (PMMA), followed by mild thermal treatment, a hybrid PMMA-based MXene-AgNW (MXAg@PMMA) electrode in which the work function of an MXAg hybrid FTE physically embedded in PMMA (MXAg@PMMA) can be tuned by controlling the amount of MXene in the hybrid film facilitates the development of a high-performance solution-processed QLED that exhibits maximum external quantum and current efficiencies of approximately 9.88% and 25.8 cd/A, respectively, with excellent bending stability. This work function-tunable flexible transparent electrode based on solution-processed nanoconductors provides a way to develop emerging high-performance, wearable, cost-effective, and soft electroluminescent devices.

Highly sandwich-structured silver nanowire hybrid transparent conductive films for flexible transparent heater applications

Hybridization with other materials has been an effective method to improve the photoelectric performance and stability of silver nanowire (AgNW) based transparent conductive films (TCFs). In the work, hybrid TCFs with a sandwiched structure composed of MXene, AgNW, and graphene were proposed. MXene sheets in the bottom acted as the intermediate layer between substrates and AgNWs could significantly improve the adhesion, graphene could be used as protective layer, and both filled the AgNW network to improve conductivity and flatness. As a result, the TCF displayed good photoelectric performance (14.4 Ω/sq with 87.5% transmittance at 550 nm), low surface roughness, enhanced adhesion and stability. Furthermore, transparent heaters (THs) were fabricated with the MXene/AgNW/graphene hybrid TCFs. The THs exhibited uniform heating distribution, fast thermal response, good repeatability and long-term working stability. Therefore, flexible THs proposed are expected to be widely used in defogging systems, smart windows, and other flexible electronic devices.

Self-template synthesis of Co3O4 nanotube for efficient Hg0 removal from flue gas

The adsorption of elemental mercury (Hg0) is a widely used technology to remove Hg0 from flue gas. The morphology and structure of sorbents, which have serious impacts on the number and availability of adsorption sites and the mass transfer of Hg0, play an important role in Hg0 removal process. Nanotube materials have through-pore structures leading to lower mass transfer resistance and more adsorption sites for Hg0. Given this, organic–inorganic hybrid nanowires were prepared by hydrothermal method as self-template. After calcination with a controlling heating rate and temperature, a series mesoporous Co3O4 nanotube sorbents were obtained. Characterization results show that the heating rate mainly affects the pore structure of the sorbents, while the calcination temperature mainly affects the surface morphology. When the calcination temperature is 400 °C and the calcination rate is 0.5 °C /min, the sorbent (Co3O4-T400-R0.5) has a clear 1D tubular structure which can effectively reduce the mass transfer resistance. And the unique internal surface of the tubular structure can provide more active sites, which can effectively avoid the competitive adsorption of Hg0 and other gas components. Furthermore, Co3O4-T400-R0.5 has the highest Co3+/Co2+ ratio leading to a better redox property, which is of benefit to Hg0 removal process. Therefore, the Hg0 removal efficiency of Co3O4-T400-R0.5 can reach more than 90% with a high gas hourly space velocity of 90,000 h− 1 and 0.02 g loading amount at 250 °C. Furthermore, Co3O4-T400-R0.5 has excellent Hg0 removal efficiencies in different flue gas condition showing a high stability.

Dandelion‐like Nanospheres Synthesized by CoO@CuO Nanowire Arrays for High‐Performance Asymmetric Supercapacitors

AbstractRecently, three‐dimensional‐structure materials have attracted enormous attention in energy‐storage fields on account of their excellent electrochemical performance. In this study, hierarchical nanospheres consisting of mesoporous CoO@CuO nanowires on a three‐dimensional conductive Ni foam are prepared by a one‐step hydrothermal method combined with a subsequent annealing process. Compared to CoO or CuO alone, the as‐obtained CoO@CuO/Ni hybrid nanowires show good electronic conductivity owning to the abundant existence of O vacancies in them. In a three‐electrode system, the area capacitance of the prepared CoO@CuO/Ni electrode reaches 2.94 F cm−2 (1.32 C cm−2) at 1 mA cm−2, and the CoO@CuO/Ni electrode presents an outstanding cycle performance. Moreover, a CoO@CuO/Ni//AC ASC asymmetric supercapacitor is fabricated and found to display a high energy density of 20.22 Wh kg−1 at 800 W kg−1. Hence, this novel CoO@CuO/Ni hybrid nanowires with excellent electrochemical properties shows outstanding potential in the practical application of high‐energy storage devices.

Supercurrent parity meter in a nanowire Cooper pair transistor.

We study a Cooper pair transistor realized by two Josephson weak links that enclose a superconducting island in an InSb-Al hybrid nanowire. When the nanowire is subject to a magnetic field, isolated subgap levels arise in the superconducting island and, because of the Coulomb blockade, mediate a supercurrent by coherent cotunneling of Cooper pairs. We show that the supercurrent resulting from such cotunneling events exhibits, for low to moderate magnetic fields, a phase offset that discriminates even and odd charge ground states on the superconducting island. Notably, this phase offset persists when a subgap state approaches zero energy and, based on theoretical considerations, permits parity measurements of subgap states by supercurrent interferometry. Such supercurrent parity measurements could, in a series of experiments, provide an alternative approach for manipulating and protecting quantum information stored in the isolated subgap levels of superconducting islands.

Design of a nanocytosensor for isolation and electrochemical detection of folate-overexpressed circulating tumor cells

Magnetic nanomaterial-based electrochemical cytosensor holds great promise to tackle the challenges in isolation and detection of circulating tumor cells (CTCs) by the combination of the selectivity of magnetic cell separation with high sensitivity of electrochemical sensing platforms. Herein, by leveraging nanomaterials with L-cysteine and folic acid, we design innovative biomaterials for electrochemical cell detection, with minimal materials and materials manufacturing steps. Folic acid-L-cysteine-capped CoFe2O4 nanoparticles (CCF) are developed to magnetically capture folate-overexpressed tumor cells. Hybrids of L-cysteine-folic acid and silver nanowires (FAgNWs) are synthesized using a green, convenient and template-free approach without any surfactant. Direct immobilization of L-cysteine and folic into silver nanowires hybrids facilitates the electrode preparation and cell detection. The density functional theory and molecular dynamics simulations were also used to provide deep insight into the interaction of silver nanowires with L-cysteine coupled with folic acid (LCFA). An affordable nanocytosensor is proposed for the detection of CTCs by sandwiching the MCF-7 cells captured between CCF and FAgNWs. This nanocytosensor has the low detection limit of 5 MCF-7 cells/mL with the wide dynamic range of 50–106 cells/mL. The presented nanomaterial-based sensing platform is promising for convenient cell isolation and detection.

1D-on-1D core–shell cobalt iron selenide @ cobalt nickel carbonate hydroxide hybrid nanowire arrays as advanced battery-type supercapacitor electrode

Sluggish kinetics and poor structural stability are two main obstacles hampering the exploration of transition metal selenides (TMSs) for supercapacitor. Developing a reasonable core–shell heterostructure with unique morphology is an effective approach to resolve these issues. Herein, a core–shell cobalt iron selenide (CoFe2Se4) @ cobalt nickel carbonate hydroxide (CoNi-CH) heterostructure is directly fabricated on carbon cloth via an electrodeposition method followed by a hydrothermal reaction. In this well-defined heterostructure, one-dimensional (1D) CoFe2Se4 nanowires function as the cores and CoNi-CH nanowires as the shells, which combines the merits of highly conductive CoFe2Se4 for rapid electron transfer and highly electroactive CoNi-CH for multiple redox reactions. Further, the intimate interaction between CoNi-CH and CoFe2Se4 realizes large surface area with hierarchical network and generates rich heterointerfaces with modified the electronic structure. By virtue of its facile 1D-on-1D nanoarchitecture and synergistic effect, the CoFe2Se4@CoNi-CH electrode delivers a increased specific capacity of 218.6 mAh g−1 at 1 A-1 and enhanced rate capability (65.5% at 20 A g−1) compared with pure CoFe2Se4 and CoNi-CH. Besides, a hybrid supercapacitor is established by coupling CoFe2Se4@CoNi-CH cathode and porous carbon anode, which enjoys a maximum energy density of 67.3 Wh kg−1 at 765.9 W kg−1 and prominent durability with 85.4% of capacity retention over 20,000 cycles.

Equilibrated PtIr/IrOx Atomic Heterojunctions on Ultrafine 1D Nanowires Enable Superior Dual-Electrocatalysis for Overall Water Splitting.

Dual-active-sites atomically coupled on ultrafine 1D nanowires (NWs) can offer synergic atomic heterojunctions (AHJs) and high atomic-utilization toward multipurpose and superior catalysis. Here, ≈2-nm-thick PtIr/IrOx hybrid NWs are elaborately synthesized with equilibrated Pt/IrOx AHJs as high-efficiency bifunctional electrocatalysts for overall water splitting. Mechanism studies reveal the atomically coupled Pt-IrOx dual-sites are favorable for facilitating water dissociation, alleviating the binding of H* on Pt sites and inversely regulating the *OH adsorption and oxidation on bridge Ir-Ir sites. By simply equilibrating the Pt-IrOx ratio, the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) can be substantially accelerated. In particular, Pt-rich PtIr/IrOx -30 NWs attain 11-fold enhancements for HER compared to Pt/C in 1.0 m KOH, while IrOx -rich PtIr/IrOx -50 NWs express about five times mass activity referring to Ir/C for OER. Remarkably, the ratio-optimized PtIr/IrOx NWs electrode couple achieves a durably continuous H2 production under a substantially low cell voltage.

Curvature control of the superconducting proximity effect in diffusive ferromagnetic nanowires

Coupling a conventional s-wave superconductor to a ferromagnet allows, via the proximity effect, to generate superconducting triplet correlations. This feature can be employed to achieve a superconducting triplet spin-valve effect in superconductor-ferromagnet (SF) hybrid structures, for example by switching the magnetizations of the ferromagnets between parallel and antiparallel configurations in F1SF2 and SF1F2 trilayers, or in SF bilayers with both Rashba and Dresselhaus SOC. It was recently reported that geometric curvature can control the generation of long ranged triplets. We use this property to show that the superconducting critical temperature of an SF hybrid nanowire can be tuned by varying the curvature of the ferromagnetic side alone, with no need of another ferromagnet or SOC. We show that the variation of the critical temperature as a function of the curvature can be exploited to obtain a robust, curvature-controlled, superconducting triplet spin-valve effect. Furthermore, we perform an analysis with the inclusion of spin-orbit coupling and explain how it modifies the spin-valve effect both quantitatively and qualitatively.

Design of hybrid solar cell with GaAs1−xBix (x = 0.01) nanowire core and conformally coated P3HT/ITO shell

The optoelectronic characteristics of the vertically aligned conformally coated radial junction, core–shell nanowire (NW) hybrid solar cell (HSC) having a core active layer of GaAs0.99Bi0.01as acceptor and donor shell layer of poly(3-hexylthiophene-2,5-diyl) (P3HT), have been investigated. Since axial junction solar cells (SCs) have been experimentally showing better efficiency as compared to their radial counterpart, our objective is to improve the efficiency of radial pn junction nanowire solar cells. In order to achieve that, the geometrical parameters, including the core diameter, shell thickness comprising P3HT layer and ITO for a fixed pitch of 480 nm are optimized. A fixed thickness of 10 nm is considered for P3HT due to a diffusion length of 20 nm. 3D finite-difference time-domain (FDTD) method has been employed to examine the effect of geometrical parameter variation on carrier generation and a detailed study has been presented. The core diameter of our proposed structure is 160 nm (Rcore = 80 nm) and the thickness of the surrounding shell is considered to be 90 nm (Rshell = 90 nm) for further optoelectronic performance study. The absorption spectra, generation rate profile and electric field profiles for the wavelength (λ) range of 400–900 nm have been presented for depicting the improvement caused due to incorporation of conformal coating of P3HT on core GaAs0.99Bi0.01 NW. An extensive investigation on the variation of electrical performance parameters such as open circuit voltage (Voc), short circuit current (Jsc), fill factor (FF) and power conversion efficiency (PCE) with carrier lifetime and surface recombination velocity (SRV) is performed for a fixed core and shell doping. An efficiency of 19% is achieved for the device featuring minority carrier lifetime of 60 ns and sufficiently high SRV of 105cm/s at the contacts for lightly doped core (∼1 × 1016 cm−3) and heavily doped shell (∼1 × 1019 cm−3) and substrate (∼1 × 1019 cm−3).

High efficient pH-universal photo-Fenton degradation of antibiotics by amorphous FeSiB microspheres decorated TiO2 nanowire hybrid film

Immobilized reactors with catalyst films fixed in are widely used for photodegradation of water pollutants, in which the photocatalyst film is critical for the reactors’ performance. In this work, trace amount of amorphous FeSiB microspheres decorated TiO2 nanowires hybrid films were fabricated by the simple painting method, and they exhibit excellent photodegradability for antibiotic contaminants. The heterogenous photocatalytic films were characterized by microscopic, spectroscopic and photoelectrochemical techniques, and were demonstrated with great tetracycline degradation at universal pH conditions between 2 and 12. By optimizing the FeSiB content in the composite film, it was found that the film containing 1 wt% FeSiB exhibited the best performance with the tetracycline degradation efficiencies of 98.2% (pH = 2) and 85.5% (pH = 12) within 4 h. Furthermore, the FeSiB/TiO2 hybrid films exhibited a high degradation efficiency of > 80% after 3 recycling, and the enhanced reusability was attributed to the corrosion resistance of FeSiB microspheres wound by the TiO2 nanowires. This study combines the merits of FeSiB metallic glass and TiO2 nanowires to improve their degradation performance of antibiotics through building the Z-Scheme FeSiB-TiO2 heterojunction, which accelerated the separation of photogenerated electrons/holes on the photocatalyst films and the conversion between Fe2+ and Fe3+ in the photo-Fenton reactions.

Correction to: Optical constants, photoluminescence and thermogravimetry of ZnS–ZnO hybrid nanowires synthesized via vapor transport

Correction to: Optical constants, photoluminescence and thermogravimetry of ZnS–ZnO hybrid nanowires synthesized via vapor transport

Selective area epitaxy of PbTe-Pb hybrid nanowires on a lattice-matched substrate

Topological quantum computing is based on braiding of Majorana zero modes encoding topological qubits. A promising candidate platform for Majorana zero modes is semiconductor-superconductor hybrid nanowires. The realization of topological qubits and braiding operations requires scalable and disorder-free nanowire networks. Selective area growth of in-plane InAs and InSb nanowires, together with shadow-wall growth of superconductor structures, have demonstrated this scalability by achieving various network structures. However, the noticeable lattice mismatch at the nanowire-substrate interface, acting as a disorder source, imposes a serious obstacle along with this roadmap. Here, combining selective area and shadow-wall growth, we demonstrate the fabrication of PbTe-Pb hybrid nanowires - another potentially promising Majorana system - on a nearly perfectly lattice-matched substrate CdTe, all done in one molecular beam epitaxy chamber. Transmission electron microscopy shows the single-crystal nature of the PbTe nanowire and its atomically sharp and clean interfaces to the CdTe substrate and the Pb overlayer, without noticeable inter-diffusion or strain. The nearly ideal interface condition, together with the strong screening of charge impurities due to the large dielectric constant of PbTe, hold promise towards a clean nanowire system to study Majorana zero modes and topological quantum computing.

Optical constants, photoluminescence and thermogravimetry of ZnS–ZnO hybrid nanowires synthesized via vapor transport

Optical constants, photoluminescence and thermogravimetry of ZnS–ZnO hybrid nanowires synthesized via vapor transport

Hierarchical Nanocapsules of Cu-Doped MoS2@H-Substituted Graphdiyne for Magnesium Storage.

Hierarchical nanocomposites, which integrate electroactive materials into carbonaceous species, are significant in addressing the structural stability and electrical conductivity of electrode materials in post-lithium-ion batteries. Herein, a hierarchical nanocapsule that encapsulates Cu-doped MoS2 (Cu-MoS2) nanopetals with inner added skeletons in an organic-carbon-rich nanotube of hydrogen-substituted graphdiyne (HsGDY) has been developed for rechargeable magnesium batteries (RMB). Notably, both the incorporation of Cu in MoS2 and the generation of the inner added nanoboxes are developed from a dual-template of Cu-cysteine@HsGDY hybrid nanowire; the synthesis involves two morphology/composition evolutions by CuS@HsGDY intermediates both taking place sequentially in one continuous process. These Cu-doped MoS2 nanopetals with stress-release skeletons provide abundant active sites for Mg2+ storage. The microporous HsGDY enveloped with an extended π-conjugation system offers more effective electron and ion transfer channels. These advantages work together to make this nanocapsule an effective cathode material for RMB with a large reversible capacity and superior rate and cycling performance.