Tellurium Nanowires Research Articles

Ultra-high sensitivity infra-red detection and temperature effects in a graphene–tellurium nanowire binary hybrid

The optoelectronic performance of hybrid devices from graphene and optically sensitive semiconductors exceeds conventional photodetectors due to a large in-built optical gain. Tellurium nanowire (TeNW), being a narrow direct band gap semiconductor (∼0.65 eV), is as an excellent potential candidate for near infra-red (NIR) detection. Here we demonstrate a new graphene-TeNW binary hybrid that exhibits a maximum photoresponsivity of ∼106 A W-1 at 175 K in the NIR regime (920 nm-1720 nm), which exceeds the photoresponsivity of the most common NIR photodetectors. The resulting noise-equivalent power (NEP) is as low as 2 × 10-18 W Hz-1/2, and the specific detectivity (D*) exceeds 5 × 1013 cm Hz1/2 W-1 (Jones). The temperature range of optimal operation, which extends up to ≈220 K and ≈260 K for 1720 nm and 920 nm excitation, respectively, is primarily limited by the electrical conductivity of the TeNW layer, and can further be improved by lowering of the defect density as well as inter-wire electronic coupling.

Kinetically Controlled Synthesis of Pt-Based One-Dimensional Hierarchically Porous Nanostructures with Large Mesopores as Highly Efficient ORR Catalysts.

Rational design and construction of Pt-based porous nanostructures with large mesopores have triggered significant considerations because of their high surface area and more efficient mass transport. Hydrochloric acid-induced kinetically controlled reduction of metal precursors in the presence of soft template F-127 and hard template tellurium nanowires has been successfully demonstrated to construct one-dimensional hierarchical porous PtCu alloy nanostructures with large mesopores. Moreover, the electrochemical experiments demonstrated that the PtCu hierarchically porous nanostructures synthesized under optimized conditions exhibit enhanced electrocatalytic performance for oxygen reduction reaction in acid media.

A hybrid method for the synthesis of small Bi0.5Sb1.5Te3 alloy particles

A reduction in the grain size of p-type thermoelectric materials, which increases phonon scattering at grain boundaries, can increase the figure of merit (ZT) due to decreased lattice thermal conductivity. Small grains are often observed in samples sintered from small powders. In this study, we investigated the effect of a reduction in powder size in Bi0.5Sb1.5Te3 alloys synthesized using a new hybrid method. Tellurium (Te) nanowires were chemically synthesized without an organic surfactant and Bi0.25Sb0.75 powders were physically synthesized using a ball-milling method. The Bi0.5Sb1.5Te3 powders synthesized from the previously prepared Te nanowires and Bi0.25Sb0.75 powder were thermally alloyed by a solid state reaction. The morphology of the Te was found to be important in determining the powder size of the alloyed Bi0.5Sb1.5Te3. Reduced thermal conductivity was associated with smaller grain size, which enhanced thermoelectric properties.

Air-stable n-type tellurium nanowires coordinated by large organic salts

Chemically-synthesized semiconductor nanostructures have the potentials for the exploration of unprecedented electronic and thermoelectric properties. Such materials possess the surface area much larger than their bulk forms, resulting that surface chemical functionalization may alter electronic properties. Here we report on the modulation of majority carriers in semiconductor nanowires by the addition of organic salts. The p-type nanowires were successfully converted to n-type forms to which large cations such as onium ions and metal-crown ether complexes are coordinated.

Electrodeposition of high aspect ratio single crystalline tellurium nanowires from piperidinium-based ionic liquid

Template-free electrodeposition of high aspect ratio Te nanowires is presented. Nanowires were obtained from the ionic liquid 1-ethyl-1-octyl-piperidinium bis(trifluoromethylsulfonyl)imide (EOPipTFSI) containing 1-ethyl-1-octyl-piperidinium bromide (EOPipBr). The influence of the EOPipBr content on the dimensions and the morphology of the nanostructures was studied. Several micrometers long tellurium nanowires with diameters between 100 and 180nm were obtained when the EOPipBr content of the electrolyte is higher than 0.5mol%. By decreasing the bromide concentration, the electrochemical behavior of TeIV solutions becomes more complex, leading to several reduction signals. By varying the applied overpotential, hair-like single crystalline nanowires can then be obtained with a diameter which can reach 50nm and a length of 70μm leading to a high aspect ratio of almost 2000. High Resolution Transmission Electron Microscopy analyses show that the nanostructures are single crystalline and reveal a growth along the c-axis, with a smooth interface. No surface contaminants were observed by Scanning Transmission Electron Microscopy, proving that halide ions do not play the role of capping agents.

Sustainable Hydrothermal Carbonization Synthesis of Iron/Nitrogen-Doped Carbon Nanofiber Aerogels as Electrocatalysts for Oxygen Reduction.

It is urgent to develop new kinds of low-cost and high-performance nonprecious metal (NPM) catalysts as alternatives to Pt-based catalysts for oxygen reduction reaction (ORR) in fuel cells and metal-air batteries, which have been proved to be efficient to meet the challenge of increase of global energy demand and CO2 emissions. Here, an economical and sustainable method is developed for the synthesis of Fe, N codoped carbon nanofibers (Fe-N/CNFs) aerogels as efficient NPM catalysts for ORR via a mild template-directed hydrothermal carbonization (HTC) process, where cost-effective biomass-derived d(+)-glucosamine hydrochloride and ferrous gluconate are used as precursors and recyclable ultrathin tellurium nanowires are used as templates. The prepared Fe/N-CNFs catalysts display outstanding ORR activity, i.e., onset potential of 0.88 V and half-wave potential of 0.78 V versus reversible hydrogen electrode in an alkaline medium, which is highly comparable to that of commercial Pt/C (20 wt% Pt) catalyst. Furthermore, the Fe/N-CNFs catalysts exhibit superior long-term stability and better tolerance to the methanol crossover effect than the Pt/C catalyst in both alkaline and acidic electrolytes. This work suggests the great promise of developing new families of NPM ORR catalysts by the economical and sustainable HTC process.

Three-Dimensional Hierarchical Reduced Graphene Oxide/Tellurium Nanowires: A High-Performance Freestanding Cathode for Li-Te Batteries.

Three-dimensional aerogel with ultrathin tellurium nanowires (TeNWs) wrapped homogeneously by reduced graphene oxide (rGO) is realized via a facile hydrothermal method. Featured with high conductivity and large flexibility, the rGO constructs a conductive three-dimensional (3D) backbone with rich porosity and leads to a free-standing, binder-free cathode for lithium-tellurium (Li-Te) batteries with excellent electrochemical performances. The cathode shows a high initial capacity of 2611 mAh cm(-3) at 0.2 C, a high retention of 88% after 200 cycles, and a high-rate capacity of 1083 mAh cm(-3) at 10 C. In particular, the 3D aerogel cathode delivers a capacity of 1685 mAh cm(-3) at 1 C after 500 cycles, showing pronounced long-cycle performance at high current density. The performances are attributed to the well-defined flexible 3D architecture with high porosity and conductivity network, which offers highly efficient channels for electron transfer and ionic diffusion while compromising volume expansion of Te in charge/discharge. Owing to such advantageous properties, the reported 3D rGO/tellurium nanowire (3DGT) aerogel presents promising application potentials as a high-performance cathode for Li-Te batteries.

Influence of ion beam irradiation induced defects on the structural, optical and electrical properties of tellurium nanowires

In this study, tellurium nanowires were electrodeposited into the polymer membranes from aqueous acidic bath containing HTeO2+ ions. The field emission scanning electron microscopy (FESEM) images confirmed the formation of uniform and straight nanowires. The influence of 110 MeV Ni8+ ion irradiation induced defects on the structural, optical and electrical properties of as–deposited tellurium nanowires were examined using X-ray diffraction (XRD), UV–visible absorption spectroscopy and current–voltage (I–V) measurements. The XRD data depicted the hexagonal phase of tellurium nanowires and further revealed a variation in the intensity of diffraction peaks of ion irradiated nanowires. Williamson–Hall (WH) analysis is used for convoluting the size and microstrain contributions to the width of diffraction peaks. Tellurium nanowires exhibited a distinct absorbance band in the visible region at 686 nm, while this was absent in bulk tellurium. Electrical properties of nanowires are explored on the basis of I–V curves, which revealed a significant increase in the electrical conductivity of irradiated nanowires. A possible mechanism for the enhanced electrical conductivity is the increase in carrier concentration due to thermally excited defects. The defects produced by ion irradiation play a vital role in modifying the properties of semiconducting nanowires.

Radial thermoelectric generator fabricated from n‐ and p‐type conducting polymers

ABSTRACTElectrically conducting polymers are attractive for thermoelectric generators (TEGs) because of their low thermal conductivity and solution processability. In this article, we report on the performance of a radial device made from n‐ and p‐type polymers printed on paper substrates. Our thermoelectric (TE) models predict an optimized geometry for a radial device that operates under natural convective cooling alone, and herein, we report on the fabrication and performance of this new organic TEG. We used poly(nickel‐1,1,2,2‐ethenetetrathiolate) blended with poly(vinylidene fluoride)/dimethyl sulfoxide as the n‐type material and poly(3,4‐ethylenedioxythiophene)/poly(styrene sulfonate) with Tellurium nanowires as the p‐type materials coated on paper to evaluate the TE performance. The radial TEG produced an open‐circuit voltage of 85 mV and a power density of 15 nW/cm2 under a 45‐K temperature difference. This proof of concept was the first demonstration of a polymer‐based radial TEG that accommodated a hot pipe as the heat source and did not require active cooling because of heat spreading. This is promising for scalable and low cost TE devices for self‐powered sensor networks. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44060.

Unique Necklace‐Like Phenol Formaldehyde Resin Nanofibers: Scalable Templating Synthesis, Casting Films, and Their Superhydrophobic Property

1D necklace‐like nanostructures have exhibited different potential applications due to their unique geometry and property. However, their macroscopic and controllable synthesis has been a challenge. Herein, a facile and scalable template‐directed hydrothermal process is reported to synthesize a series of necklace‐like phenol‐formaldehyde resin (PFR) wrapped nanocables. The 1D templates involved in the synthesis can be various, such as tellurium nanowires (TeNWs), silver nanowires, and carbon nanotubes. After removal of the TeNWs template, pure PFR necklace‐like nanofibers with different morphologies can be prepared. Owning to their multiscale roughness and formed 3D network structures, such necklace‐like PFR nanofibers can be further used as building blocks for constructing robust superhydrophobic coatings with excellent mechanical properties on various substrates.

Carrier Scattering at Alloy Nanointerfaces Enhances Power Factor in PEDOT:PSS Hybrid Thermoelectrics.

This work demonstrates the first method for controlled growth of heterostructures within hybrid organic/inorganic nanocomposite thermoelectrics. Using a facile, aqueous technique, semimetal-alloy nanointerfaces are patterned within a hybrid thermoelectric system consisting of tellurium (Te) nanowires and the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) ( PSS). Specifically, this method is used to grow nanoscale islands of Cu1.75Te alloy subphases within hybrid PSS-Te nanowires. This technique is shown to provide tunability of thermoelectric and electronic properties, providing up to 22% enhancement of the system's power factor in the low-doping regime, consistent with preferential scattering of low energy carriers. This work provides an exciting platform for rational design of multiphase nanocomposites and highlights the potential for engineering of carrier filtering within hybrid thermoelectrics via introduction of interfaces with controlled structural and energetic properties.

Tellurium Nanowire Arrays-Based Nanogenerators for Thermal Energy Harvesting

Semiconductor nanorods and nanowires are interesting nanomaterials and have been applied in sensor and energy applications. Tellurium is a typical p-type semiconductor having bandgap energy of 0.35 eV and has already been recognized as an interesting material for fabricating nanodevices. For examples, tellurium nanowires have shown great potential in the applications of nanogenerators, supercapacitor, lithium battery, and biosensors. In this paper, we developed a thin, light-weight, and flexible thermoelectric nanogenerator based on the nanocomposite of tellurium nanowire arrays and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The Seebeck coefficient of the nanocomposite was determined to be 235 μV/K. A linear relationship between the output voltage and the temperature difference across the thermoelectric nanogenerator was observed. We demonstrated that the thermoelectric nanogenerator can be integrated with fiber fabric and harvested the thermal energy from human body temperature. Not only for the purpose of energy harvesting, the thermoelectric nanogenerator can also function as a self-powered sensor for water temperature measurement.

Development of Functional Triboelectric Nanogenerators for Antibacterial Applications

Pathogenic bacteria that give rise to diseases every year remain a major health concern. In recent years, tellurium-based nanomaterials have been approved as new and efficient antibacterial agents. In this paper, we developed the approach to directly grow tellurium nanowires onto commercial carbon fiber fabric and demonstrated that they can be used as triboelectric and antibacterial materials. During the operation of the as-prepared triboelectric nanogenerator, the release of tellurite (TeO3 2‒) ions would help to suppress the growth of Escherichia coli (E. coil) cells. We also studied the effect of electric output on the antibacterial activity. Higher electric output would contribute the better antibacterial activity. In addition, compared to Ag nanoparticles that are commonly used as antibacterial reagents, tellurium nanowires can provide higher antibacterial activity and lower toxicity.

Charged Inorganic Nanowire‐Directed Mineralization of Amorphous Calcium Carbonate

AbstractCharged inorganic nanowires (e.g., tellurium nanowires, TeNWs), analogous to supramolecular templates, have been used to direct the mineralization of uniform amorphous calcium carbonate (ACC) shells on their surfaces. The role of surface charges of TeNWs, mixed solvent ratio, and the diameter of the TeNWs is discussed, and the formation mechanism of ACC‐coated tellurium nanowires (ACC@TeNWs) is elucidated. This charged‐nanowire‐directed mineralization process represents a new approach that could be extended for the synthesis of other amorphous inorganic nanostructures in the future.

Fabrication of Te and Te-Au Nanowires-Based Carbon Fiber Fabrics for Antibacterial Applications.

Pathogenic bacteria that give rise to diseases every year remain a major health concern. In recent years, tellurium-based nanomaterials have been approved as new and efficient antibacterial agents. In this paper, we developed the approach to directly grow tellurium nanowires (Te NWs) onto commercial carbon fiber fabrics and demonstrated their antibacterial activity. Those Te NWs can serve as templates and reducing agents for gold nanoparticles (Au NPs) to deposit. Three different Te-Au NWs with varied concentration of Au NPs were synthesized and showed superior antibacterial activity and biocompability. These results indicate that the as-prepared carbon fiber fabrics with Te and Te-Au NWs can become antimicrobial clothing products in the near future.

Facile Synthesis of Tellurium Nanowires and Study of Their Third-Order Nonlinear Optical Properties

We report on the synthesis of single-crystalline tellurium nanowires with different aspect-ratios prepared via facile surfactant-assisted synthesis under mild conditions. Short and long Te nanowires were synthesized by the reduction of tellurium dioxide by hypophosphorous acid with the assistance of polyoxyethylene (23) laurylether and cetyltrimethylammonium bromide, respectively. We obtained uniform single-crystal Te nanowires with diameter below 30 nm and tunable length from 600 nm to 5 µm. Short and long Te nanowires showed remarkable nonlinear absorption and their third-order nonlinear optical properties were investigated by the Z-scan technique with single 80 ps laser pulses at 532 nm. For the first time, it was observed a distinguished switching behavior from saturated absorption to reverse saturated absorption as a function of the laser intensity in one-dimensional Te nanostructures. Although both short and long Te nanowires display such interesting behavior, the short ones exhibited superior optical limiting performance.

Templating synthesis of ternary PtPdTe nanowires with tunable diameter for methanol electrooxidation

Ternary PtPdTe nanowires (NWs) with controllable diameter can be synthesized using tellurium nanowires (TeNWs) as templates for methanol electrooxidation. Among the PtPdTe NWs with different diameters, the nanowires with a diameter of 40 nm exhibit the highest electrocatalytic activity. This principle could serve as a guide for future studies in the field of nanowire-based electrocatalysts and offer an additional parameter for optimizing the electrocatalytic performance.

Coiling ultrathin tellurium nanowires into nanorings by Pickering emulsion.

Well-defined hydrophilic ultrathin tellurium nanowires (TeNWs) can be coiled into nanorings by Pickering emulsion at room temperature.

Power factor enhancement via simultaneous improvement of electrical conductivity and Seebeck coefficient in tellurium nanowires/reduced graphene oxide flexible thermoelectric films

The simultaneous improvement of electrical conductivity (σ) and Seebeck coefficient (S) is essential to realize the thermoelectric materials with high power factor value. Here, we report the discovery that the redox reaction happened between the reduced graphene oxide (RGO) sheets and tellurium (Te) nanowires can lead to a simultaneous improvement of σ and S in the RGO/Te nanowires hybrid films. With optimization, the electrical conductivity and Seebeck coefficient can reach 633S/m and 382μV/K, respectively, pushing the power factor value up to 68.4μW/(mK2), approximately 25 times larger than the reported pure Te nanowires film. Based on all of the characterizations, the redox reaction between the RGO sheets and Te nanowires have been confirmed and the transportation characteristics of the hybrid films are predicted. We demonstrate the new approach that via turning the redox reaction, the interfacial interaction can be optimized, enabling a novel flexible thermoelectric films with superior performance. To our knowledge, this is the first time that the TE properties of RGO/inorganic hybrid films are reported.

Macroscopic-scale synthesis of nitrogen-doped carbon nanofiber aerogels by template-directed hydrothermal carbonization of nitrogen-containing carbohydrates

Doping heteroatoms into carbon nanomaterials will greatly enhance their physiochemical properties, however, it is still challenging to prepare doped nanocarbons in large-scale by economical ways for industrial applications. Here, we report the macroscopic-scale synthesis of a new class of nitrogen-doped carbonaceous nanofibers (N-CNFs) aerogels with diameter from tens to hundreds nanometers by a template-directed hydrothermal carbonization (HTC) process, where ultrathin tellurium nanowires (TeNWs) as templates and nitrogen-containing carbohydrates as carbon sources. High-temperature treatment and CO2 activation of the N-CNFs endow them with high conductivity and porosity, resulting in outstanding performances as electrode materials for electrocatalysts and supercapacitors.