Te Nanowires Research Articles

Template-directed synthesis of one-dimensional hexagonal PdTe nanowires for efficient ethanol electrooxidation.

A template-directed synthesis of one-dimensional hexagonal PdTe nanowires using Te nanowires as a template through a two-step hydrothermal process is developed, which exhibit excellent mass activity of 4.4 A mgPd-1 for ethanol electrooxidation in an alkaline medium. This work enriches the controlled synthesis of one-dimensional noble metal chalcogenide nanomaterials.

Toward a Procedure for the Template Free Growth of Te Nanowires Across an Insulator by Electrodeposition.

In this work, we present a method for direct, site-selective growth of tellurium nanowires by electrochemical deposition. The Te nanowires were grown laterally between two specially designed nanoband electrodes across a gap, and over a dielectric material, forming a lateral device structure directly. The resulting wires are crystalline and phase pure, as evidenced by Raman spectroscopy, EDS (energy dispersive X-ray spectroscopy), and ADF-STEM (annular dark field scanning transmission electron microscopy). The precise conditions for lateral growth of the nanowires were investigated and the fabrication of an electronic device from the as-deposited material, without the need for any transfer process or further contact fabrication, is demonstrated.

Room-temperature ferroelectric, piezoelectric and resistive switching behaviors of single-element Te nanowires

Ferroelectrics are essential in memory devices for multi-bit storage and high-density integration. Ferroelectricity mainly exists in compounds but rare in single-element materials due to their lack of spontaneous polarization in the latter. However, we report a room-temperature ferroelectricity in quasi-one-dimensional Te nanowires. Piezoelectric characteristics, ferroelectric loops and domain reversals are clearly observed. We attribute the ferroelectricity to the ion displacement created by the interlayer interaction between lone-pair electrons. Ferroelectric polarization can induce a strong field effect on the transport along the Te chain, giving rise to a self-gated ferroelectric field-effect transistor. By utilizing ferroelectric Te nanowire as channel, the device exhibits high mobility (~220 cm2·V−1·s−1), continuous-variable resistive states can be observed with long-term retention (>105 s), fast speed (<20 ns) and high-density storage (>1.92 TB/cm2). Our work provides opportunities for single-element ferroelectrics and advances practical applications such as ultrahigh-density data storage and computing-in-memory devices.

Electrodeposition of bismuth, tellurium and bismuth telluride through sub-10 nm mesoporous silica thin films

Templated electrodeposition is an efficient technique for the bottom-up fabrication of nanostructures and can effectively control the size and shape of the electrodeposits. Here, mesoporous silica thin films with highly ordered mesopores and a regular three-dimensional mesostructure were synthesised as templates for electrodeposition. The mesoporous silica films have small mesopores (∼8 nm) and complex mesopore channels (Fmmm mesostructure with the [0 1 0] axis perpendicular to the substrate). Electrodeposition of bismuth, tellurium and bismuth-tellurium was investigated from electrolytes containing [NnBu4][BiCl4], [NnBu4]2[TeCl6] and [NnBu4]Cl dissolved in dry dichloromethane. Top-view SEM images showed Bi, Te and Bi doped-Te nanoparticles in the mesopores and cross-section SEM showed there were a few Te nanowires, in addition to the particle aggregations on the surface. This is a promising observation as it demonstrates the possibility of preparing sub-10 nm nanowires by templated electrodeposition even though the deposits are not uniformly electrodeposited in all the mesopores. EDX shows the deposited Bi-Te nanoparticles were tellurium-rich, XRD shows they were trigonal tellurium (ICSD 65692). A variety of parameters including the choice of pulsed electrodeposition conditions and [NnBu4][BiCl4] concentration (2.25 mM and 3 mM) were investigated in order to control the composition of the deposit. All samples prepared by pulsed electrodeposition showed very low Bi:Te ratio (Bi/Te<0.02), whereas samples deposited for 5 min at −0.6 V achieved high Bi content (Bi/Te=0.49).

Oxidation Control to Augment Interfacial Charge Transport in Te-P3HT Hybrid Materials for High Thermoelectric Performance.

Organic-inorganic hybrid thermoelectric (TE) materials have attracted tremendous interest for harvesting waste heat energy. Due to their mechanical flexibility, inorganic-organic hybrid TE materials are considered to be promising candidates for flexible energy harvesting devices. In this work, enhanced TE properties of Tellurium (Te) nanowires (NWs)- poly (3-hexylthiophene-2, 5-diyl) (P3HT) hybrid materials are reported by improving the charge transport at interfacial layer mediated via controlled oxidation. A power factor of ≈9.8µW(mK2)-1 is obtained at room temperature for oxidized P3HT-TeNWs hybrid materials, which increases to ≈64.8µW(mK2)-1 upon control of TeNWs oxidation. This value is sevenfold higher compared to P3HT-TeNWs-based hybrid materials reported in the literature. MD simulation reveals that oxidation-free TeNWs demonstrate better templating for P3HT polymer compared to oxidized TeNWs. The Kang-Snyder model is used to study the charge transport in these hybrid materials. A large σE0 value is obtained which is related to better templating of P3HT on oxygen-free TeNWs. This work provides evidence that oxidation control of TeNWs is critical for better interface-driven charge transport, which enhances the thermoelectric properties of TeNWs-P3HT hybrid materials. This work provides a new avenue to improve the thermoelectric properties of a new class of hybrid thermoelectric materials.

Interfacial construction of 2D Au74Pt23Te3 nanotrough array for boosting alcohol electrooxidation

Two-dimensional (2D) Pt-based multi-metallic nanostructures have been demonstrated to be used as outstanding electrocatalysts for direct alcohol fuel cell owing to the merits of raising electrocatalytic activity and enhancing the durability of catalysts as well as saving Pt utilization. Herein, we develop an interface-confined strategy, achieving 2D close-packed AuPtTe nanotrough array. This strategy involves two steps: (1) assembly of Te nanowires into 2D monolayer array at hexane/water interfaces, and (2) transformation of 2D interfacial Te nanowire array into AuPtTe nanotrough array by interface-confined etching of PtCl62– and AuCl4– in the water subphase. Optimized 2D Au74Pt23Te3 nanotrough array exhibits ∼3.36 and ∼2.15 A mgAu+Pt–1 in the mass activity towards ethanol and methanol electrooxidation, respectively, ∼5 and 3 times that of commercial Pt/C, and shows superior durability to Pt/C, which may be attributed to the synergistic effects of the trough-like morphology and optimal composition. This work may open up a new perspective on the designing of components, morphologies, and compositions of advanced catalysts.

Investigations of Morphology and Carrier Transport Characteristics in High‐Performance PEDOT:PSS/Tellurium Binary Composite Fibers Produced via Continuous Wet‐Spinning

AbstractFiber‐based flexible thermoelectric (TE) generators are highly desirable due to their capability to convert thermal energy into electricity and their potential applications in wearable electronics. High‐performance poly(3,4‐ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/Tellurium (Te) composite TE fibers have been successfully developed via a continuous wet‐spinning approach followed by sulphuric acid treatment. With a simple pre‐modification to Te nanowires, the inorganic Te fillers form uniform distribution in PEDOT:PSS. At the optimal condition, the composite fibers exhibit a power factor of 233.5 µW m−1 K−2 and mechanical strength of 205 MPa, which are among the highest values reported so far for the PEDOT:PSS‐based TE fibers. From the viewpoint of TE property enhancement mechanism, understanding the morphology and carrier transport behavior in the 1D organic/inorganic composite fibers remains still challenging. On basis of a series of PEDOT:PSS/Te composite fibers with varying Te fractions, orientations of both the inorganic and organic constituents are quantitatively evaluated. Their electrical conductivities and Seebeck coefficients are also analyzed with modified series‐parallel models and energy filtering theory. This work may not only provide a universal approach to produce high‐performance organic/inorganic composite TE fibers for various wearable applications, but also help to understand the morphology and charge transport between heterogeneous phases in a 1D composite.

Chemically Transformed Ag2 Te Nanowires on Polyvinylidene Fluoride Membrane For Flexible Thermoelectric Applications.

Flexible thermoelectric devices of nanomaterials have shown a great potential for applications in wearable to remotely located electronics with desired shapes and geometries. Continuous powering up the low power flexible electronics is a major challenge. We are reporting a flexible thermoelectric module prepared from silver telluride (Ag2 Te) nanowires (NWs), which are chemically transformed from uniquely synthesized and scalable tellurium (Te) NWs. Conducting Ag2 Te NWs composites have shown an ultralow total thermal conductivity ~0.22 W/mK surpassing the bulk melt-grown Ag2 Te ~1.23 W/mK at ~300 K, which is attributed to the nanostructuring of the material. Flexible thermoelectric device consisting of 4 legs (n-type) of Ag2 Te NWs on polyvinylidene fluoride membrane displays a significant output voltage (Voc ) ~2.3 mV upon human touch and Voc ~18 mV at temperature gradient, ΔT ~50 K, which shows the importance of NWs based flexible thermoelectric devices to power up the low power wearable electronics.

Chemically Transformed Ag2Te Nanowires on Polyvinylidene Fluoride Membrane For Flexible Thermoelectric Applications

AbstractFlexible thermoelectric devices of nanomaterials have shown a great potential for applications in wearable to remotely located electronics with desired shapes and geometries. Continuous powering up the low power flexible electronics is a major challenge. We are reporting a flexible thermoelectric module prepared from silver telluride (Ag2Te) nanowires (NWs), which are chemically transformed from uniquely synthesized and scalable tellurium (Te) NWs. Conducting Ag2Te NWs composites have shown an ultralow total thermal conductivity ~0.22 W/mK surpassing the bulk melt‐grown Ag2Te ~1.23 W/mK at ~300 K, which is attributed to the nanostructuring of the material. Flexible thermoelectric device consisting of 4 legs (n‐type) of Ag2Te NWs on polyvinylidene fluoride membrane displays a significant output voltage (Voc) ~2.3 mV upon human touch and Voc ~18 mV at temperature gradient, ΔT ~50 K, which shows the importance of NWs based flexible thermoelectric devices to power up the low power wearable electronics.

Te nanowires: facile synthesis and application in the preparation of PtTe nanowires for ammonia oxidation

Te nanowires prepared at room temperature were employed as templates to synthesize PtTe nanowires, which exhibit excellent electrocatalytic performance for ammonia oxidation.

Fabrication and characterization of hybrid thermoelectric materials based on aligned nanowires.

This study introduces the synthesis of a hybrid thermoelectric material with enhanced conductivity and a high Seebeck coefficient, leveraging the properties of Te nanowires (NWs) and the conductive polymer PEDOT:PSS. Te NWs were synthesized using the galvanic displacement reaction. To further enhance conductivity, Ag-Te NWs were synthesized under optimized conditions via the Ag topotactic reaction, achieving desired results within 7min using ethylene glycol and AgNO3. This hybrid material exhibited an electrical conductivity of 463S/cm, a Seebeck coefficient of 69.5μV/K at 300K, and a power factor of 260μW/mK2. These metrics surpassed those of conventional Te/PEDOT:PSS hybrids by a factor of 3.6, highlighting the superior performance of our approach. This study represents a significant advancement in thermoelectric materials, improving both conductivity and efficiency.

Hidden nontrivial Berry phase and spin-zero effect in Te nanowires

Hidden nontrivial Berry phase and spin-zero effect in Te nanowires

Photonic and phononic properties of oriented 5 nm diameter tellurium nanowires

We study polarized optical absorption and Raman spectra (OAS and RS) of ∼5 nm diameter tellurium (Te) nanowires (NWs) confined in chrysotile asbestos nanotubes packed parallel to each other into nearly-perfect-hexagonal lattice. Te was encapsulated into the nanotubes from molt using ∼20 kbar pressure. Asbestos with Te NWs (asb-Te) shows a high OAS/RS anisotropy due to a strong NW-light interaction for the light polarized papallel to NWs (E//c) and a weak one for the light polarized perpendicular to NWs. Importantly, asb-Te RS display bands of confined acoustic phonons at ∼9 cm−1 and ∼23 cm−1, specific signatures of 5 nm diameter Te NWs. Density-functional-theory calculation shows agreement with the observed frequencies and flattening of NW acoustic phonon dispersions useful for thermo-electricity. Asb-Te optical phonon A1-mode Raman band displays frequency upshift compared to the bulk-Te band due to enhancement of the intrachain bonds on expense of interchain ones. Asb-Te 2nd-order RS confirm this. Surprisingly, E-modes display LO-phonon RS-activity in asb-Te instead of TO-phonon-activity in bulk-Te. We observe enhancement of the NW Raman signal compared to that of bulk Te, which is associated with the Mie-resonance-induced NW-light interaction enhancement for E//c, which is important for photonic and photo-electric applications.

Co-reduction assisted fabrication of PdCuTe nanowires for enhanced glycerol electrooxidation

High-performance electrocatalysts for glycerol oxidation are highly craved for the direct glycerol fuel cells. Herein, trinary PdCuTe nanowires with well-defined nanostructure was prepared through a co-reduction assisted approach with Te nanowires as the starting template. The addition of ascorbic acid is the key for introduction of Cu into the PdTeCu nanowires during synthesis. Electrochemical results revealed that the incorporation of Cu could enhance the performance for glycerol electrooxidation, which rendering the as-fabricated PdCuTe nanowires afford the highest current density of 61.1 mA cm−2. Owe to the improved electrooxidation kinetics and reduced charge transfer resistance, the resultant PdCuTe nanowires also demonstrated a better long-term stability. The synthetic strategy proposed herein is useful for the preparation of other materials, and the developed catalysts herein may also find wide applications in electrochemical-related fields.

Engineering composition-varied Au/PtTe hetero-junction-abundant nanotrough arrays as robust electrocatalysts for ethanol electrooxidation

Pt-based multi-metallic electrocatalysts containing hetero-junctions are found to have superior catalytic performance to composition-equivalent counterparts. However, in bulk solution, controllable preparation of Pt-based hetero-junction electrocatalyst is an extremely random work owing to the complexity of solution reactions. Herein, we develop an interface-confined transformation strategy, subtly achieving Au/PtTe hetero-junction-abundant nanostructures by employing interfacial Te nanowires as sacrificing templates. By controlling the reaction conditions, composition-varied Au/PtTe can be easily obtained, such as Au75/Pt20Te5, Au55/Pt34Te11, and Au5/Pt69Te26. Moreover, each Au/PtTe hetero-junction nanostructure appears to be an array consisting of side-by-side Au/PtTe nanotrough units and can be directly used as a catalyst layer without further post-treatment. All Au/PtTe hetero-junction nanostructures show better catalytic activity towards ethanol electrooxidation than commercial Pt/C because of the combining contributions of Au/Pt hetero-junctions and the collective effects of multi-metallic elements, where Au75/Pt20Te5 exhibits the best electrocatalytic performance among three Au/PtTe nanostructures owing to its optimal composition. This study may provide technically feasible guidance for further maximizing the catalytic activity of Pt-based hybrid catalysts.

Van der Waals nanomesh electronics on arbitrary surfaces

Chemical bonds, including covalent and ionic bonds, endow semiconductors with stable electronic configurations but also impose constraints on their synthesis and lattice-mismatched heteroepitaxy. Here, the unique multi-scale van der Waals (vdWs) interactions are explored in one-dimensional tellurium (Te) systems to overcome these restrictions, enabled by the vdWs bonds between Te atomic chains and the spontaneous misfit relaxation at quasi-vdWs interfaces. Wafer-scale Te vdWs nanomeshes composed of self-welding Te nanowires are laterally vapor grown on arbitrary surfaces at a low temperature of 100 °C, bringing greater integration freedoms for enhanced device functionality and broad applicability. The prepared Te vdWs nanomeshes can be patterned at the microscale and exhibit high field-effect hole mobility of 145 cm2/Vs, ultrafast photoresponse below 3 μs in paper-based infrared photodetectors, as well as controllable electronic structure in mixed-dimensional heterojunctions. All these device metrics of Te vdWs nanomesh electronics are promising to meet emerging technological demands.

Single‐Orientation Epitaxy of Quasi‐1D Tellurium Nanowires on M‐Plane Sapphire for Highly Uniform Polarization Sensitive Short‐Wave Infrared Photodetection

AbstractTellurium (Te), an elemental van der Waals semiconductor, has intriguing anisotropic physical properties owing to its inherent quais‐1D crystal structure. Synthesizing ultrathin Te crystal with uniform orientation is important to its large‐scale device applications, but that remains a great challenge. Herein, the nanoscale grooves‐induced unidirectional epitaxy growth of 1D Te nanowires via physical vapor deposition on the annealed m‐plane sapphire is demonstrated. By enhancing the annealing temperature from 1000 to 1300 °C, nanoscale grooves on m‐plane sapphire arising along the [100] direction and gradually distinct, and the corresponding Te nanowires grown on them turns from random to uniform, finally achieving nearly 95% unidirectional Te nanowires. The as‐grown Te nanowires possess high crystallinity with clearly chiral helical chains along the c‐axis direction and reveal thickness‐tunable bandgap with prominent linear‐dichroic. As results, the Te nanowire‐based photodetectors demonstrate a broadband photoresponse from visible (532 nm) to short‐wave infrared (2530 nm), with high responsivity of 327 A W−1 as well as strong and uniform polarization sensitivity (anisotropic ratio = 2.05) to 1550 nm light. The high crystallinity and superior anisotropy of Te nanowires, combined with the orientation‐controlled preparation endows it with great feasibility for constructing chip‐scale multifunctional optoelectronic devices.

Van der waals epitaxial growth of mixed-dimensional 1D/2D heterostructures with tellurium nanowires and transition metal dichalcogenide nanosheets for nonlinear optical applications

One-dimensional (1D) tellurium (Te) nanowires (NWs) have triggered intense attention due to their remarkable properties in electronics, optoelectronics and nonlinear optics. However, the saturable absorption properties of Te NWs and the ability to be bleached by strong pulsed energy need to be further improved. Van der Waals (vdW) heterostructures based on two-dimensional (2D) transition metal dichalcogenides (TMDCs) exhibit prominent nonlinear optical properties. Direct epitaxial growth of large-area 1D/2D Te-TMDC vdW heterostructures is still rarely investigated. Herein, we demonstrate the controllable epitaxial growth of large-scale 1D/2D vertical Te-TMDC heterostructures via two-step vapor phase deposition method. Our experimental results have confirmed that the saturable absorption properties of as-prepared Te-TMDC heterostructures can be obviously enhanced. The first principle calculations and surface potential measurements demonstrate that effective interlayer charge transfer between Te NWs and TMDC nanosheets is beneficial for promoting the saturable absorption properties. Systematic investigation of vdW Te-TMDC heterostructures with nonlinear optical properties is vital for the next generation of nanophotonics and integrated photonics, which paves the way for the development of saturable absorbers and light modulators based on Te-TMDC vdW heterostructures.

Vesicular AuPd alloy nanowires for enhanced electrocatalytic activity

Developing excellent fuel cells requires complex design and precise tuning of catalyst structure and composition. This paper presents a simple approach to fabricate AuPd vesicular nanowires (VNWs) with controlled composition. The method uses homogeneous Te nanowires (NWs) as templates and reducing agents in the replacement reaction and NaClO as etching agent. Bimetallic synergism and rich catalytic sites in the vesicular nanowires give AuPd catalysts the excellent electrocatalytic performance for methanol oxidation. In particular, the Au28Pd71 VNWs showed the highest electrocatalytic activity for methanol oxidation, and its highest mass current density was1.278 A mg−1, which was 1.22 and 1.65 times that of Pt VNWs and commercial Pt/C, separately. Furthermore, Au28Pd71 VNWs exhibited good stability after 2000 cycles, maintaining an initial mass current density of 85.2%. As the optimal component ratio, Au28Pd71 exhibited superior electrocatalytic performance for methanol oxidation. This discovery demonstrated a new approach for the programming and fabrication of senior methanol fuel cells electrocatalysts.

Quantum confinement in optically active ultrathin (Cd,Mn)Te/(Cd,Mg)Te core/shell nanowires

The fabrication of ultrathin (Cd,Mn)Te nanowires with diameters reaching values below 10 nm is reported. The thinning procedure relies on a thermally induced reverse reaction process applied to (Cd,Mn)Te nanowires grown using the vapor-liquid-solid method. The impact of quantum confinement is manifested by a distinct blueshift of the excitonic emission from individual nanowires. Cathodoluminescence mapping reveals that the optical emission originates from relatively short nanowire segments, which is explained in terms of exciton localization on irregularities of nanowire core diameter. Magneto-optical study performed on several individual nanowires reveals a change from light hole to heavy hole character of the excitonic emission depending on the emission energy, i.e., on the size of the emitting object. The results are interpreted in terms of the influence of axial and radial quantum confinement on excitons in ultrathin nanowires.