Nanowire Layer Research Articles

Ultratough and self‐healable electromagnetic interference shielding materials with sandwiched silver nanowires in polyurethane composite films

AbstractThis study presents a facile self‐healing electromagnetic interference (EMI) shielding composite by sandwiching a layer of silver nanowires (AgNWs) between two layers of self‐healing polyurethane (SPU). The AgNWs layer forms an interconnected conductive network that effectively reflects and absorbs electromagnetic radiation, providing efficient EMI shielding. The SPU layers contribute autonomous healing of mechanical damages and restoring structural integrity and conductive pathways. The composite films exhibit remarkable EMI shielding effectiveness (SE) (up to 64.6 dB), exceptional mechanical toughness (106.4 MJ/m3), and self‐healing capabilities, outperforming conventional shielding materials. The synergy between AgNWs and SPU layers offers lightweight, flexible, tough, and self‐healing properties, making this material highly promising for applications in wearable electronics, aerospace, and automotive industries where durability and long‐term reliability are critical.Highlights Facile fabrication of sandwiched AgNWs layer between SPU films. Sandwiched AgNWs/SPU films with exceptional EMI shielding. AgNWs form conductive networks for efficient EMI shielding. Remarkable mechanical toughness of 106.4 MJ/m3 and self‐healing capability. Potential shielding materials for lightweight, wearable electronics, aerospace.

Coercivity of (Fe0.7Co0.3)2B Nanowire and Its Bonded Magnet

(Fe0.7Co0.3)2B are potential permanent magnets material due to its large saturation magnetization and high Curie temperature. However, it has moderate magnetocrystalline anisotropy (MCA) and low coercivity. One way to improve its coercivity is to combine the contributions from magnetocrystalline- and magnetic-shape anisotropy by preparing (Fe0.7Co0.3)2B nanowires. We study the effects of size, morphology, and surface defects on the hard magnetic properties of nanowires using micromagnetic simulation. The hard magnetic properties of (Fe0.7Co0.3)2B nanowire-bonded magnets are estimated, including the role of inter-wire magnetostatic interaction. By considering the existence of local reductions in MCA energy of up to 30% on the surface layer of nanowires, the anisotropic bonded magnet with a 65% vol. of (Fe0.7Co0.3)2B nanowires would have typical remanence, Br= 7.6–8.4 kG, coercivity, Hci= 9.6–9.9 kOe, and maximum energy product, (BH)m = 14–17.8 MGOe. Developing effective technology for synthesizing nanowires and fabricating corresponding bonded magnets is promising for manufacturing practical magnets based on the magnetic phase with a relatively low or moderate MCA, such as (Fe0.7Co0.3)2B.

Enhancing Proton Co-Intercalation in Iron Ion Batteries Cathodes for Increased Capacity.

Recently, aqueous iron ion batteries (AIIBs) using iron metal anodes have gained traction in the battery community as low-cost and sustainable solutions for green energy storage. However, the development of AIIBs is significantly hindered by the limited capacity of existing cathode materials and the poor intercalation kinetic of Fe2+. Herein, we propose a H+ and Fe2+ co-intercalation electrochemistry in AIIBs to boost the capacity and rate capability of cathode materials such as iron hexacyanoferrate (FeHCF) and Na4Fe3(PO4)2(P2O7) (NFPP). This is achieved through an electrochemical activation step during which a FeOOH nanowire layer is formed in situ on the cathode. This layer facilitates H+ co-intercalation in AIIBs, resulting in a high specific capacity of 151 mAh g-1 and 93% capacity retention over 500 cycles for activated FeHCF cathodes. We found that this activation process can also be applied to other cathode chemistries, such as NFPP, where we found that the cathode capacity is doubled as a result of this process. Overall, the proposed H+/Fe2+ co-insertion electrochemistry expands the range of applications for AIBBs, in particular as a sustainable solution for storing renewable energy.

Significantly improved electrical conductivity and cycling stability of manganese dioxide by poly (3,4-ethylene-dioxythiophene) coating

Abstract Manganese dioxide (MnO2) is widely acknowledged as a prospective pseudocapacitive material aimed at alleviating the issue of low energy density in supercapacitors. Nevertheless, hampered by its intrinsic low conductivity and poor structural stability, MnO2-based energy storage materials often exhibit lower practical capacity in practical applications. During this investigation, the synthesis of MnO2@PEDOT (poly(3,4-ethylenedioxythiophene)) composite materials involved an in-situ oxidative polymerization approach, whereby PEDOT nanowires were integrated onto the MnO2 nanoparticle surface. Notably, the internal configuration of the MnO2@PEDOT composite material demonstrated a high surface area morphology, while the externally entwined PEDOT nanowire layer further expanded the material’s specific surface area. As a result, the MnO2@PEDOT composite material demonstrated a specific capacitance reaching 214 F g-1, a 91% improvement compared to unmodified MnO2. Furthermore, the winding of PEDOT nanowires effectively suppressed the structural disintegration of MnO2. The MnO2@PEDOT composite material exhibited a remarkable improvement in cycling stability, maintaining 81% of its initial capacity after 5000 cycles. The electron-rich PEDOT not only improved the conductivity of the inner MnO2 through electron migration but also prevented MnO2 structural degradation by tightly enveloping it. The outcomes of our study propose a method for constructing MnO2 featuring a structurally stable configuration and a prolonged cycling lifespan, offering valuable insights for designing electrode materials with high cycling stability in supercapacitors.

Anisotropy of the conductivity of silicon nanowires

ABSTRACT This study reports the findings from an investigation into charge carrier transport within a silicon nanowire layer. The samples were prepared using the metal-assisted chemical etching method applied to crystalline silicon wafers with a resistance of 10–20 Ω·cm. The resulting silicon nanowires had a diameter of about 100 nm with a resistance of approximately 15 kΩ·cm. Electrical conductivity measurements were performed in both planar and sandwich configurations, revealing analogous conductivity mechanisms across different geometries. Frequency-dependent conductivity studies unveiled the presence of hopping conductivity. A hypothesis is proposed regarding the existence of a potential barrier at the interface between the nanowire layer and the substrate.

Deformable Joule heating electrode based on hybrid layers of silver nanowires and carbon nanotubes and its application in a refreshable multi-cell Braille display.

Stretchable electrodes are an essential component in soft actuator systems. In particular, Joule heating electrodes (JHEs) are required for thermal actuation systems. A highly stretchable, patternable, and low-voltage operating JHE based on hybrid layers of silver nanowires (AgNWs) and carbon nanotubes (CNTs) is reported. The conductive layers were applied on a locally pre-strained bistable electroactive polymer (BSEP) membrane to form a wrinkled conductive surface with a low resistance of 300 Ω/sq, and subsequently patterned to a serpentine trace by laser engraving. The resistance of the resulting electrode remains nearly unchanged up to ~80-90% area strain. By applying a voltage of 7 - 9 V to the electrode, the temperature of the BSEP membrane increased to more than 60 °C, well above the polymer's phase transition temperature of 46 °C, thereby lowering its modulus by a factor of 103. An electronic Braille device based on the JHEs on a BSEP membrane was assembled with a diaphragm chamber. The electrode was patterned into 3 × 2 individually addressable pixels according to the standard U.S. Braille cell format. Through Joule heating of the pixels and local expansion of the BSEP membrane using a small pneumatic pressure, the pixels deformed out of the plane by over 0.5 mm to display specific Braille letters. The Braille content can be refreshed for 20,000 cycles at the same operating voltage.

A novel dual-functional flexible dimming film for smart window applications: Energy saving and self-cleaning performance

Polymer dispersed liquid crystal (PDLC) is a promising candidate for electrically controlled smart window applications because of its energy efficiency, convenience and other advantages. However, its flexibility and heat management capabilities are not effectively evaluated. Herein, a flexible dual-functional intelligent window based on PDLC composite is designed for this purpose, which integrates Ag nanowires as a transparent conductive electrode (TCE) and Tm3+/Yb3+-CsxWO3 (Tm3+/Yb3+-CWO) as a near-infrared shielding and air purification layer. Specifically, the as-made smart window can control the transmission of both visible and near-infrared light. Furtherly, it also possesses self-cleaning capability. A series of characterization has been carried out. The resistance of the Ag nanowire layer is measured to be 22.47 Ω/sq and the transmittance reaches 78.8 %. Flexibility test shows that when the bending radius is 4 mm, the resistance value of the TCE changes only 6 % after 500 repetitions, indicating good flexibility and stability. The spectrum examination reveals that the near-infrared light shielding efficiency achieves 80 % and the average transmittance of visible light is 76.7 %. The degradation of Rhodamine B (RhB) is used to evaluate the purification performance and result shows that the degradation percentage reaches 70 % in 120 min. Heat-regulation simulation test discloses that the indoor temperature can be decreased by 10 °C. Compared to traditional PDLC windows, the designed flexible window has broader application prospects in areas of architecture, vehicle glass, military stealth materials and so on.

Multilayered silver nanowires and graphene fluoride-based aramid nanofibers for excellent thermoconductive electromagnetic interference shielding materials with low-reflection

Multilayered films composed of alternating layers of graphene fluoride (GF) and silver nanowires (AgNWs) in an aramid nanofiber (ANF) matrix were fabricated. The films were prepared by sequential vacuum filtration of GF@ANF and AgNWs@ANF suspensions to obtain multilayered composite architectures. The multilayered GF@ANF/AgNWs@ANF films exhibited exceptional mechanical flexibility and strength, with tensile strength up to 130 MPa and 5000 bending cycles with negligible performance deterioration. The films displayed remarkably high electromagnetic interference (EMI) shielding effectiveness up to 54 dB in X-band frequencies, attributed to the multiple internal reflections in the multilayered structure. EMI shielding was dominated by absorption rather than reflection, enabling attenuation of incident microwaves without secondary pollution. The multilayered films also exhibited ultrahigh in-plane thermal conductivity of up to 45 W/mK, owing to the thermally conductive GF and AgNWs networks. The EMI shielding effectiveness and thermal conductivity were retained after temperature and bending cycling. The composite films also demonstrated excellent flame retardancy. This study provides an effective route toward concurrent enhancement of multi-functional properties through architectural engineering at the nanoscale. The combination of robust EMI shielding, mechanical flexibility, thermal management, and fire safety highlights the potential of rationally designed multilayered composites for practical applications in 5 G wearable electronics devices, communications systems, and radar technologies.

Lithiophilic interlayer driven ‘bottom-up’ metal infilling in high current density Li-metal anodes

A functional interlayer is designed to inhibit dendrite formation in Li metal anodes. The single-sided lithiophilic germanium nanowire layer on carbon cloth promotes bottom-up Li infilling during the plating process.

Ablation behavior of HfC coatings modified by novel HfxTa1-xC solid solution nanowires under oxyacetylene flame

HfC exhibits great potential for ablation resistant coating of carbon/carbon composites due to its ultra-high melting point and high temperature resistance. In this work, we proposed to develop the novel HfxTa1-xC solid solution nanowires with perfect ultra-high temperature property and unique one-dimensional (1D) nanostructures to modify HfC coating for further improved ablation resistance of the coating. Results showed that the novel Hf0.5Ta0.5C solid solution nanowires exhibited excellent ablation resistance, which could maintain 1D morphology under oxyacetylene flame ablation above 2100 °C. In addition, the morphology of Hf0.5Ta0.5C solid solution nanowire layer exhibited significant effect on the morphology and ablation behavior of coatings. The linear ablation rate of HfC anti-ablation coating with porous Hf0.5Ta0.5C solid solution nanowire layer decreased by 60.87 % compared with that without nanowires. Our works provide a basis for enhancing the protective ability of coatings under severe ablation environments.

Direct detection of dopamine using zinc oxide nanowire-based surface plasmon resonance sensor

This study uses an angle interrogation approach to propose an SF11 Prism- Ag– ZnO nanowires-CeO2-Sensing layer-based surface plasmon resonance sensor. The proposed multilayer structure has been used for the concentration measurement of dopamine in human blood. The thicknesses of the ZnO nanowire (ZnO-NW) and cerium oxide (CeO2) layer have been taken as 50 nm and 0.5 nm, respectively, and the thickness of the metal layer is 50 nm considered. The characteristics and parameters are also measured for the proposed sensor. The sensitivity, full width at half maximum (FWHM), detection accuracy (DA), and quality factor (QF) are obtained as 95 deg/RIU, 14.34 deg, 0.06578 deg−1, and 6.24 RIU−1, respectively. Numerous neurological illnesses are brought on by abnormalities of dopamine (D. A.), a crucial neurotransmitter in the brain's neural circuits. Quick and sensitive sensors for D. A. detection are needed to diagnose these illnesses early. The significance of this sensor in the biomedical field.

Brushed Nano‐Stirbars for Measuring Viscosity in Microscopic Systems

AbstractConventional methods for measuring viscosity rely on macroscopic device components, which are difficult to miniaturize. The magnetic nano‐stirbars are small enough to enter tiny spaces and can spin without precise installation, making them an ideal candidate for exploring new methods. It is shown that a dense layer of Au nanowires can be grown on the silica surface of the nano‐stirbars, as a means to modulate the viscous resistance during their spinning and to make them visible under an optical microscope. The uniform growth of Au nanowires and the slight fluctuation of the spinning rates are investigated. It is shown that the nano‐stirbars with the hairy layer of Au nanowires can be used to measure the viscosity in microscopic liquid systems, such as microfluidic chambers and capillary tubes, involving cell media and blood samples. It is believed that the success with the proof‐of‐concept tests will open a window for further miniaturization of the nano‐stirbars for measuring in ultrasmall systems.

Self‐Charging Dual‐Modal Sensor for Glucose Monitoring Based on Piezoelectric Nanowire/Microgel Hybrid Film

AbstractContinuous monitoring of bio/physiological signals will play an essential role in personalized, patient‐centric medicine in the future healthcare industry. One of the challenges involves providing a sustainable, energy‐efficient operation for long‐term monitoring devices. The current technology based on power sources requires periodic replacement. Here, a hybrid film composed of a layer of piezoelectric nanowire (PVDFHFP) and a layer of microgel (pNIPAM‐APBA) is presented that continuously monitors glucose, does not rely on enzymes, is self‐charging, and decouples changes in read‐out signals due to glucose detection from the force is applied to activate self‐charging. By characterizing self‐charging/discharging properties, the operation and sensing mechanism for the nanowire/microgel hybrid film are proposed. A reasonable sensitivity of 70 mV mm−1 with a high linearity value of R2 = 0.9956 is observed. This work demonstrates the potential for use in a self‐charging wearable platform that enables continuous monitoring of bio/physiological signals.

An ITO-Free Kesterite Solar Cell.

Photovoltaic thin film solar cells based on kesterite Cu2 ZnSn(S, Se)4 (CZTSSe) have reached 13.8% sunlight-to-electricity conversion efficiency. However, this efficiency is still far from the Shockley-Queisser radiative limit and is hindered by the significant deficit in open circuit voltage (VOC ). The presence of high-density interface states between the absorber layer and buffer or window layer leads to the recombination of photogenerated carriers, thereby reducing effective carrier collection. To tackle this issue, a new window structure ZnO/AgNW/ZnO/AgNW (ZAZA) comprising layers of ZnO and silver nanowires (AgNWs) is proposed. This structure offers a simple and low-damage processing method, resulting in improved optoelectronic properties and junction quality. The ZAZA-based devices exhibit enhanced VOC due to the higher built-in voltage (Vbi ) and reduced interface recombination compared to the usual indium tin oxide (ITO) based structures. Additionally, improved carrier collection is demonstrated as a result of the shortened collection paths and the more uniform carrier lifetime distribution. These advances enable the fabrication of the first ITO-free CZTSSe solar cells with over 10% efficiency without an anti-reflectivecoating.

Spatiotemporally Controllable Electrical Stimulator via Independent Photobending and Upconversion Photoluminescence Using Two Different Wavelengths of Near-Infrared/Visible Light as Dual Stimuli.

Multistimuli responsive materials are advantageous in that they can enhance the desired response or bypass unwanted reactions. Light is one of the most attractive stimuli since it allows remote spatiotemporal control and multiplexing of properties (e.g., wavelength, intensity, irradiation time, pulsed/continuous wave) for application on multiphotoresponsive materials. However, the operating wavelength for such photoresponsive systems often includes an ultraviolet (UV) range that limits its use in the biomedical field. Herein, we investigate near-infrared (NIR)/visible (Vis) light-responsive nanocomposite films composed of rare earth element (i.e., Yb, Er)-doped NaYF4 nanoparticles (NPs) embedded in azobenzene-incorporated poly(dimethylsiloxane) (AzoPDMS), silk fibroin, and silver nanowire (AgNW) layers. Photobending (PB) of the nanocomposite film is induced by a Vis light of 400-700 nm, while upconversion photoluminescence (UCPL) of embedded NPs is activated by an NIR light of 980 nm. The excitation wavelength of photoluminescence (PL) is shifted to the NIR (λ = 980 nm) range via photon upconversion in rare earth element-doped NPs. Independent operation of PB and UCPL enables both on-demand electrical switching and real-time location monitoring for spatiotemporally controlled electrical pulse stimulation. As a result, the dual-photoresponsive nanocomposite film can be utilized as a remotely controllable electrical stimulator and location indicator via different wavelengths of light.

An all-nanofibrous Janus textile with directional perspiration for triboelectric nanogenerator and self-powered e-skin sensor

Due to the increased demand for health monitoring and disease alarm, the self-powered epidermal electric sensors have attracted extensive attention, such as triboelectric nanogenerator (TENG)-based electric skin (e-skin). However, the humidity accumulation at the interface between e-skin and skin will threaten the stability and reliability of the monitoring signals. Moisture absorptivity and perspiration are still great challenges that need to be addressed. Here, inspired by the internal structure of plants used to transport water, we fabricated an all-nanofiber Janus textile via a continuous electrospinning/electrospray technology, presenting a double gradient variations in the pore size and wettability along the thickness direction. Janus textile was constructed from the hydrolyzed polyacrylonitrile (HPAN)/hexagonal boron nitride nanosheets (BNNS) fibrous membrane with small pores and hydrophilicity, conducting Ag nanowire (NW)layer, and polyurethane (TPU) nanofibrous membrane with large pores and hydrophobicity. By utilizing the wicking effect of external HPAN/BNNS layer, the sweat droplet could be transported from the interface between the skin and Janus textile to the external environment, meanwhile, the returned sweat will be blocked by interior TPU layer to keep the dry state of the skin. Therefore, the directional moisture transportation was realized. As the near-skin side, TPU was used as the other triboelectric layer, the optimal triboelectrification output reached 78.10 V, 0.16 μA, and 3.31 W m−2. Moreover, the damped Janus textile also exhibited an open-circuit voltage of 30 V, a short-circuit current of 0.051 μA, and a power density of 0.14 W m−2. With the assistance of an adhesive layer, Janus textile e-skin could easily adhere to the skin surface, generating stable movement and physiological sensing signals. In short, this work presents a noval way to construct Janus e-skin patch with directional sweating and breathability for monitoring long-term real-physiological signals.

Detection of hemoglobin concentration in human blood samples using a zinc oxide nanowire and graphene layer heterostructure based refractive index biosensor

Detection of hemoglobin concentration in human blood samples using a zinc oxide nanowire and graphene layer heterostructure based refractive index biosensor

Flexible multi-layered porous CuxO/NiO (x = 1, 2) photo-assisted electrodes for hybrid supercapacitors: Design and mechanism insight

With the utilization of sustainable sunlight efficiently, it is of paramount important to develop a new type of electrode for boosting photo-assisted supercapacitor performance. Herein, this work originally designs the Ni35Cu15Zr15Ti35 metallic glass (MG) ribbon as dealloying precursor. Benefiting from the different oxidation behavior of Ni and Cu metals during the dealloying and anodizing processes, a new type of multi-layered porous hybrid photoelectrode (namely CuxO/np-NiCu@NiCuO/MG, x = 1, 2) that simultaneously achieve the flexible, hierarchical porous structure as well as the NiO/Cu2O heterojunction, are successfully synthesized. An intriguing multi-layered structure consists of the outermost photosensitive CuxO nanowire layer formed by the anodizing technique, the nanoporous NiCu@NiCuO layer just beneath the nanowire layer via the dealloying as well as the glass central layer offering an excellent flexibility. In particular, 3D interconnected hierarchical porous structure is benefit to the penetration and utilization of visible light efficiently. The photoelectrode demonstrates a maximum specific capacitance of 1182.2 F cm−3 with light irradiation, which is 18% higher than that without light. This photo-assisting charging for the supercapacitor is ascribed to the combination of photosensitive CuxO and pseudocapacitive NiO components. Moreover, the photoelectrode exhibits an excellent flexibility and the photocurrent response is basically unchanged after bending for 1000 times. The aqueous supercapacitor shows a maximum energy density of 44.9 mWh cm−3 under light. This work provides new insights into the development of next generation wearable photo-assisted supercapacitor.

Silver Compositing Boosts Water Electrolysis Activity and Durability of RuO2 in a Proton‐Exchange‐Membrane Water Electrolyzer

Proton‐exchange‐membrane water electrolyzers (PEMWEs) are of particular interest for green hydrogen production, where the oxygen evolution reaction (OER) at the anode largely determines the overall efficiency. Up to now, only ultrafine IrO2 catalyst gives desirable performance, while its scarcity and high cost inhibit the widespread application. RuO2 catalyst is the most promising alternative, while its practical application is greatly hindered by poor durability. Herein, the greatly boosted performance of conventional sub‐micrometer RuO2 by compositing with Ag is reported, and both the morphology of Ag and the compositing way significantly affect the electrolysis performance. The PEMWE fabricated with a two‐layer RuO2/Ag nanowire (NWs) composite anode achieves 1.77 A cm−2 at 2.00 V, due to a prominent 44.6 times increase of the electronic conductivity, which greatly improves the catalyst utilization. In addition, mass transportation at high‐current‐density region is enhanced due to the highly porous feature of Ag NW layer. Long‐term stability under high current density of 1 A cm−2 for 100 h is proved with the composite anode, due to the suppressed degradation of RuO2 by silver compositing. This work may accelerate the widespread commercialization of PEMWEs by providing a new way for developing IrO2‐free anode.

PHOTOSENSITIVITY OF PbS COLLOIDAL QUANTUM DOTS BASED NANOSTRUCTURES WITH AN ENERGY BARRIER

A new architecture of photosensitive elements for the near (0.7–1.4 μm) and short-wavelength (1.4–3.0 μm) infrared regions of the spectrum based on hybrid nanostructures consisting of PbS colloidal quantum dots and functional layers of ZnO and AgNW silver nanowires is proposed. Small-sized (12 × 12 μm) photosensitive elements with an energy barrier at the contact between layers of n- and p-type CQDs have been studied. The current-voltage characteristics, spectral dependences of optical absorption and relative spectral photosensitivity of Si(λ)/Si(λmax) barrier structures at room temperature have been studied. It is shown that the proposed architecture of barrier structures provides photosensitivity in a wide spectral range from 0.4 µm to 2.0 µm. An excess of the average value of the relative spectral sensitivity Si(λ)/Si(λmax) about 1.5 times compared to those previously observed in the wavelength range of 0.9–1.85 μm for barrier nanostructures from PbS CQDs was found.