Copper Nanorods Research Articles

Nanoengineered thin films of copper for the optical monitoring of urine – a comparative study of the helical and columnar nanostructures

The use of nanoengineered metallic complex mediums in the monitoring of urine is investigated in this study. As to the mediums used, nanoscaled thin films comprised of (i) copper nanohelix structures of two different numbers of helical turns and (ii) columnar thin films of copper nanorods of two different slanting angles grown over planar glass surface – a dielectric medium – are taken into account. Turbadar–Kretschmann–Raether (TKR) configuration is used to couple light with the metallic nanoengineered thin films, and the absorption spectra are monitored corresponding to two different optical wavelengths. The void regions in nanoengineered metallic films are filled up with urine as the analyte, which causes to alter the constitutive properties, resulting thereby shifts in the peaks in absorption spectra. Prominent shifts in absorption peaks corresponding to nanoengineered mediums infiltrated with urine essentially confirm prudent optical sensing characteristics of the devices under consideration.

Preparation and characterization of Ti/SnO2-Sb electrode with copper nanorods for AR 73 removal

Novel Ti/Cu-NRs/SnO2-Sb electrode modified by copper (Cu) nanorods was fabricated through anodic aluminum oxide (AAO) template assisted electrochemical deposition (ECD) for wastewater treatment. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and electrochemical methods such as linear sweep voltammetry (LSV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the surface morphology, crystal structure and electrochemical performance of the electrodes. Acid dye AR 73 was selected as target pollutants to investigate the electro-catalyst behavior, and UV/vis spectroscopy was used to monitor the concentration changes with time. The results indicated that the presence of Cu nanorods on the Ti substrate promoted the electrodes' property obviously. Ti/Cu-NRs/SnO2-Sb anode possessed smaller charge transfer resistance and longer service life than Ti/SnO2-Sb anode. The oxygen evolution potential (OEP) of Ti/Cu-NRs/SnO2-Sb electrodes reach 2.17V (vs. Ag/AgCl). Removal of pollutants and reaction rate were all promoted due to the introduction of Cu nanorods in the process of AR 73 decomposing with Ti/Cu-NRs/SnO2-Sb electrodes. And specific energy consumption also reduced remarkably. Our study has shown that the fabricated Ti/Cu-NRs/SnO2-Sb electrodes are very promising for the electrochemical treatment of wastewater.

Polypyrrole thin films decorated with copper nanostructures as counter electrode for dye-sensitized solar cells

A two-step electrochemical polymerization method for the fabrication of polypyrrole (PPY) thin films decorated with copper nanostructures on a stainless steel has been employed. The PPY film thickness affects the size, shape, and the number density of the copper nanostructures and provides an easy approach to control the morphology of these nanostructures. SEM images show nanorod like structures of copper on 200 nm PPY film. By employing this composite film as counter electrode (CE), a dye-sensitized solar cell (DSSC) achieves a conversion efficiency of 7.42%, which is greater than Pt CE based DSSC (5.63%). The superior photovoltaic efficiency for the Cu-PPY film is attributed to unique porous PPY thin film and copper nanorods structure that leads to higher cathodic current density (5.38 mA/cm2), large electrocatalytic activity, and small charge transfer resistance(1.92 Ω cm−2). Therefore, Cu-PPY composite can be considered a competitive and promising CE material with the traditional and expensive Pt CE, for large-scale DSSCs production.

Catalytic Reductive Degradation of Methyl Orange Using Air Resilient Copper Nanostructures

The study describes the application of oxidation resistant copper nanostructures as an efficient heterogeneous catalyst for the treatment of organic dye containing waste waters. Copper nanostructures were synthesized in an aqueous environment using modified surfactant assisted chemical reduction route. The synthesized nanostructures have been characterized by UV‐Vis, Fourier transform infrared spectroscopy FTIR spectroscopy, Atomic force microscopy (AFM), Scanning Electron Microscopy (SEM), and X‐ray diffractometry (XRD). These surfactant capped Cu nanostructures have been used as a heterogeneous catalyst for the comparative reductive degradation of methyl orange (MO) in the presence of sodium borohydride (NaBH4) used as a potential reductant. Copper nanoparticles (Cu NPs) were found to be more efficient compared to copper nanorods (Cu NRds) with the degradation reaction obeying pseudofirst order reaction kinetics. Shape dependent catalytic efficiency was further evaluated from activation energy (EA) of reductive degradation reaction. The more efficient Cu NPs were further employed for reductive degradation of real waste water samples containing dyes collected from the drain of different local textile industries situated in Hyderabad region, Pakistan.

Original Anisotropic Growth Mode of Copper Nanorods by Vapor Phase Deposition

We report on a thermal evaporation method to synthesize copper nanorods, up to several microns long. The synthesis parameters that control the size and aspect ratio are studied to understand their influence on this anisotropic growth mode. We exploit the multifunctionalities of electron microscopy for studying the structural properties of these nanorods, in particular their growth morphology. By analyzing the face-centered cubic structure of the nanorods along several orientations, we demonstrate that their anisotropic axis is parallel to the [110] direction. The precise 3D shape of the nanorods is determined by using electron tomography, evidencing a morphology with a 2-fold symmetry and rectangular facets. This unusual faceting for metal nanorods is actually consistent with energetic considerations and arises from a growth mode that is different from the one of chemically prepared nanorods.

Modeling the oscillations of a copper nanorod using the molecular dynamics method

The dynamics of oscillation of a copper nanorod with a length of 16.4 nm and a square cross section with a side of 3.0 nm were studied using the molecular dynamics modeling method. It was found that predominantly longitudinal oscillations arise in the process of relaxation in a stressed nanorod. It was shown that the variation of its potential energy with time does not represent the oscillation dynamics in its entirety. Beats of longitudinal and transverse oscillations of an initially deviated copper nanorod were found, and its Young’s modulus was determined. The obtained results are discussed.

The Effect of Nanostructure Distribution on Subcooled Boiling Heat Transfer Enhancement over Nanostructured Plates Integrated Into a Rectangular Channel

In this study, subcooled flow boiling is investigated over nanostructured plates at flow rates ranging from 69 mL/min to 145 mL/min. The first configuration of the nanostructured plate includes ˜600-nm-long, closely packed copper nanorod arrays distributed randomly upon the surface with an average nanorod diameter of ˜150 nm, and the second configuration consists of a periodic structure having ˜600-nm-long copper (Cu) nanorods with an average nanorod diameter of ˜550 nm and a center-to-center nanorod separation of ˜1 μm. The nanorod arrays are deposited utilizing glancing angle deposition (GLAD) technique on the copper thin film (˜50 nm thick) coated on silicon wafer substrates. Dimensions of the test section, heat flux values, and flow rates are chosen to ensure that nanostructured plates remain intact along with their nanorods in their original shape and position, so that the nanostructured plates could be used for many experiments. A consistent increase (up to 30%) in heat transfer coefficients is observed on nanostructured plates compared to the Cu thin film, which is used as the control sample. However, no significant difference in the boiling heat transfer performance between the random and periodic nanorods was observed, which indicates that the distribution of nanostructures may not be very critical in achieving enhanced heat transfer. In light of the obtained promising results, channels with nanostructured surfaces are proven to be useful, particularly in applications such as cooling of small electronic devices, where conventional surface modification techniques are not applicable.

Well‐dispersed copper nanorods grown on the surface‐functionalized PAN fibers and its antibacterial activity

ABSTRACTβ‐Cyclodextrins/polyacrylonitrile/copper nanorods (β‐CDs/PAN/CuNRs) composite fibers were fabricated by two steps including the preparation for the β‐CDs/PAN composite fibers by electrospining, and the preparation of the β‐CDs/PAN/CuNRs composite fibers by adsorption and reduction. The β‐CDs/PAN/CuNRs composite fibers were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, and X‐ray photoelectron spectroscopy respectively. The results indicated that the CuNRs were not only successfully synthesized on the surface of composite fibers but also the CuNRs were distributed without aggregation on the composite fibers. Furthermore, microorganism Escherichia coli had been used to check the antibacterial efficacy of the β‐CDs/PAN/CuNRs composite fibers. Subsequently, antibacterial tests have indicated that the composite fibers have good bactericidal effects. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41011.

Copper nanorod array assisted silicon waveguide polarization beam splitter.

We present the design of a three-dimensional (3D) polarization beam splitter (PBS) with a copper nanorod array placed between two silicon waveguides. The localized surface plasmon resonance (LSPR) of a metal nanorod array selectively cross-couples transverse electric (TE) mode to the coupler waveguide, while transverse magnetic (TM) mode passes through the original input waveguide without coupling. An ultra-compact and broadband PBS compared to all-dielectric devices is achieved with the LSPR. The output ports of waveguides are designed to support either TM or TE mode only to enhance the extinction ratios. Compared to silver, copper is fully compatible with complementary metal-oxide-semiconductor (CMOS) technology.

Ordered Silver and Copper Nanorod Arrays for Enhanced Raman Scattering Created via Guided Oblique Angle Deposition on Polymer

We report the manufacture of ordered silver and copper nanorod arrays for surface-enhanced Raman scattering using oblique angle deposition (OAD) on prepatterned polymer sheets. It was found that the patterned polymer substrate defined nucleation sites which guided subsequent growth of nanorods. Enhanced surface-enhanced Raman spectroscopy (SERS) intensities of the Raman probe molecule trans-1,2-bis(4-pyridyl)ethylene (BPE) were found for Ag arrays on polymer, up to about 10 times that of the Ag–silica control. The SERS response of Ag nanorod arrays of different structures was investigated alongside results obtained from discrete dipole approximation simulations. This revealed that narrow gaps between nanorods, formed by guided nucleation during OAD, were responsible for this dramatic enhancement. Ordered Cu nanorod arrays were also successfully fabricated, producing a SERS intensity about 3 times that of Cu on silicon for both BPE and another Raman probe—rhodamine B isothiocyanate (RBITC)—highlighting the potential of this large-scale, low-cost, SERS-active substrate.

Shock-induced plasticity and the Hugoniot elastic limit in copper nano films and rods

Shock deformation of copper nano-films and nano-rods is examined with Molecular Dynamics (MD) simulations. The influence of the small system size on the onset of plasticity, its origin resulting from the nucleation of dislocation loops, and its reversible nature are determined. While simulations of large systems with periodic boundary conditions indicate that tremendous axial stresses are needed to induce plastic deformation in perfect copper crystals, the present results suggest that the stress levels needed to initiate irreversible plasticity in nano-rods are more than one order of magnitude smaller than what has been reported for bulk single crystals. MD studies of nano-films show that shock waves are purely elastic up until the Hugoniot elastic limit of PHEL ≈ 30–40 GPa, at which point Shockley partial dislocations are internally nucleated at the shock front. However, our recent experiments on shocked nano-rods show that plasticity is evident at much lower axial stress levels, on the order of 1–2 GPa. The present MD simulations of shocked nano-rods show that Shockley partial dislocations prefer to nucleate at lower stresses from the rod surface, at PHEL ≈ 1–2 GPa, consistent with our concurrent experimental observations, leading to surface step formation and mechanical damage. Nucleated dislocations are found to be Shockley partials in the [100] and [111] oriented nano-rods, with the additional presence of perfect dislocations in the latter. MD simulations of rarefaction shock waves in nano-films indicate that they can be spalled via a mechanism of nano-void nucleation, growth and coalescence at the spall plane. The origin of these nano-voids is shown to be at the intersection of stacking faults on conjugate slip {111} planes. Spallation by void nucleation and coalescence is found not to be achievable in nano-rods. Rarefaction shocks with high stresses were found to either severely deform or melt the nano-rod before it can be spalled.

Large‐Area and Flexible Lead‐Free Nanocomposite Generator Using Alkaline Niobate Particles and Metal Nanorod Filler

The lead‐free nanocomposite generator device for high‐output energy harvesting using piezoelectric alkaline niobate‐based particles (KNLN) and copper (Cu) nanorods filler is reported. To produce the piezoelectric nanocomposite (p‐NC), lead‐free KNLN particles synthesized using a solid‐state method and the Cu nanorods are distributed in a polydimethylsiloxane (PDMS) matrix. The lead‐free flexible nanocomposite generator (NCG) made by a simple spin‐casting method successfully converts mechanical energy to electricity up to 12 V and 1.2 μA. These are higher than previously reported outputs from other lead‐free and composite‐based nanogenerators. The harvested energy is utilized to directly turn on white light emitting diodes (LEDs) without external circuits and to operate a complex circuital liquid crystal display (LCD). A large‐area NCG device (30 cm × 30 cm) is also fabricated using the bar‐coating method to obtain maximum output up to 140 V and 8 μA (≈0.5 mW). This NCG technology has substantial advantages as a simple, cost‐effective, scalable, and high‐throughput approach for practical flexible electronics, bio‐eco‐compatible self‐powered systems, and body sensor networks (BSN).

Copper nanorods supported phosphorus-doped silicon for lithium storage application

Functional Cu nanorods supported P-doped Si anode was designed to improve the performance of lithium-ion batteries for high-power applications. The binder-free anode consists of an electrochemical etched Cu nanorod network coated with P-doped Si. The obtained electrode exhibits excellent rate capability and superior cyclability. At a rate of 2A/g, the anode presents a capacity of 2010mAh/g even after 80 cycles with a capacity retention of above 80%. The anode also presents a stable rate performance even at a high rate of 10A/g. The enhanced performance can be mainly ascribed to the Cu nanorod network which could result in a nanocable structure on the micro-level and play a role of scaffolding on the macro-level, as well as the nature of high conductivity and amorphism of the heavy P-doped Si coating.

CuTe Nanocrystals: Shape and Size Control, Plasmonic Properties, and Use as SERS Probes and Photothermal Agents

We report a procedure to prepare highly monodisperse copper telluride nanocubes, nanoplates, and nanorods. The procedure is based on the reaction of a copper salt with trioctylphosphine telluride in the presence of lithium bis(trimethylsilyl)amide and oleylamine. CuTe nanocrystals display a strong near-infrared optical absorption associated with localized surface plasmon resonances. We exploit this plasmon resonance for the design of surface-enhanced Raman scattering sensors for unconventional optical probes. Furthermore, we also report here our preliminary analysis of the use of CuTe nanocrystals as cytotoxic and photothermal agents.

Submerged jet impingement cooling using nanostructured plates

In this paper, the results of a series of heat transfer experiments conducted on a compact electronics cooling device based on single and two phase jet impingement technique are reported. Deionized and degassed water is propelled into four microchannels. The generated jet impingement is targeted through these channels towards the surface of two nanostructured plates with different surface morphologies placed inside a liquid pool filled with deionized-water. These nanostructured plates are composed of copper nanorods grown on top of a silicon wafer substrate of thickness 350μm coated with a 50nm thick copper thin film layer (i.e. Cu-nanorod/Cu-film/Silicon-wafer). Nanorods were grown using the sputter glancing angle deposition (GLAD) technique. First type of nanostructured plates incorporates ∼600nm long vertically aligned copper nanorod arrays. The second type incorporates ∼600nm long tilted copper nanorod arrays. Heat removal characteristics induced through jet impingement are investigated using the nanostructured plates and compared to the results obtained from a plain surface plate of copper thin film coated on silicon wafer surface. Surface temperatures are recorded by a data acquisition system with four thermocouples integrated on the surface at various prescribed locations. Volumetric flow rate and heat flux values are varied between 107.5–181.5ml/min and 1–40W/cm2. A single phase average heat transfer enhancement of 22.4% and a two phase average heat transfer enhancement of 85.3% has been realized using the nanostructured plate with vertical nanorods compared to flat plate. This enhancement is attributed to the increased heat transfer surface area and the single crystal property of the vertical Cu nanorods. On the other hand, nanostructured plate with tilted nanorods has shown poorer heat transfer performance compared to both the nanostructured plate with vertical nanorods and plain surface plate in the performed experiments. The lower heat transfer rate of the tilted Cu nanorods is believed to be due to the decreased supply of liquid jets to the base of the plate caused by their tilted orientation and closely spaced dense array structure. This leads to formation of air gaps that ultimately become trapped among the tilted nanorods, which results in reduced heat transfer surface area and increased resistance to heat transfer.

Surfactant-assisted shape control of copper nanostructures

Stable copper nanoparticles and copper nanorods have been successfully prepared in aqueous surfactant medium. The nanomaterials are stable and resistant towards aerial oxidation. The most interesting aspect of this work is that it is possible to tune the shape of the copper nanomaterials by regulating surfactant concentration.

Electrochemical elaboration of electrodes and electrolytes for 3D structured batteries

The challenges associated with the fabrication of three-dimensional (3D) electrode and electrolyte materials for Li-ion batteries are discussed. The basic issues for achieving a solid 3D cell foundation, which can simultaneously offer sufficient electronic conductivity to enable stable cycling, as well as enough compatibility with the incorporation of complementary components, have been addressed. Various electrochemical strategies for elaborating such systems are discussed and critically examined. Several current collector systems are presented including electrochemically prepared Cu and Al nanorods and commercial aperiodic carbon structures. Further electrochemical coating approaches then provide a direct method for the deposition of thin layers of active materials successfully demonstrated here as coatings on both 3D metal structures and commercially available 3D-structured carbon substrates. Enhanced capacities per foot print area are demonstrated for a number of 3D electrode materials, namely polyaniline on reticulated vitreous carbon, Cu2O on copper nanorods and TiO2 on Al nanorods. The crucial points for achieving a thin conformal coating of the corresponding 3D electrode structures with solid polymer electrolytes are also carefully analysed and discussed. In this context electro-polymerisation is proposed as a viable route to form thin electrolyte layers with promising characteristics. The high versatility of electro-polymerisation in combination with the various structures and methodologies adopted here represents a further step towards the development of cost-effective 3D microbattery devices.

A PASSIVE WIRELESS GAS SENSOR BASED ON MICROSTRIP ANTENNA WITH COPPER NANORODS

Applications of copper (Cu) nanorod arrays, produced by glancing angle deposition (GLAD) technique, which extends the function of conventional microstrip antennas to encompass passive wireless gas sensors at microwave frequencies are presented. The proposed microstrip antenna consists of Cu nanorod arrays grown on silicon wafers which were coated with thin fllms of Cu of 50nm in thickness. To study the efiect of the length of Cu nanorods on antenna performance, Cu nanorods of difierent lengths (400, 700, and 1000nm) were fabricated. The efiects of Cu nanorods morphologies (Cu thin fllm, closely-spaced Cu nanorods, and well-separated Cu nanorods), were investigated too. Conventional microstrip antennas based on sputtered Cu thin fllm were prepared for comparison. It was found that as the length of Cu nanorods increases, the antennas exhibit a wider bandwidth and lower frequency resonance than those of the conventional antennas based on Cu thin fllm. Furthermore, moving from ∞at surface to well-separated nanorods results in a decrease in the resonant frequency, while there was no observable efiect on the bandwidth. These enhancements are attributed to the mutual coupling occurring among Cu nanorods. Based on the antenna characterization, the 1000nm long Cu nanorods sample was selected for gas detection measurements due to its observed sharp resonance and narrow bandwidth. The detection mechanism is based on the change of in the magnitude of the re∞ection coe-cient as well as the resonant frequency due to the introductions of difierent gases. The proposed sensor based on Cu nanorods shows a signiflcant response in

Clustered copper nanorod arrays: a new class of adhesive hydrophobic materials

Clustered copper nanorod arrays constitute single-component, two-level hierarchical structures that mimic rose petals by showing high contact angles as well as considerable contact angle hysteresis (CAH). The cluster morphology of the nanorod arrays – electrochemically grown within porous alumina templates – is determined by the template geometry and the drying conditions. The CAH (a measure of the adhesion) is a function of the nanorod length and the cluster size to inter-cluster separation ratio. The measured pinning force was 176 μN, among the highest reported. The first level of the hierarchical nano-microstructure consists of the nanorod clusters and the air trapped between them – leading to a Cassie–Baxter type hydrophobicity. The second level comprises the tips of the clustered copper nanorods which pin the water droplets due to the inherently hydrophilic nature of metals. This conjecture is supported by fluorescence imaging and surface polymerization experiments. Thus, a clustered metal nanorod array provides a simple model system for studying the coexistence and complex interplay of hydrophobicity and adhesion, while also providing some degree of control over these mutually contradictory properties.

Length and boundary effects on a nanorod

We investigate length and boundary effects on the equilibrium strain of a ⟨100⟩ copper nanorod with {100} or {110} surfaces. Unlike a nanowire, a free-edged nanorod has finite length and has two more surfaces at both tip and root. Although the area of these two edge surfaces is generally much smaller than that of side surfaces, the effect of the edge surfaces should not be ignored in the equilibrium configuration of a nanorod. In this letter, an analytical model to estimate the equilibrium strain of the nanorod is proposed, and molecular statics simulations are performed to prove the proposed model. As the length of a nanorod increases, the equilibrium strain increases and converges to that of a nanowire. As for the boundary effect, we compare the equilibrium strain of a clamped nanorod with that of a free-edged nanorod.