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Carbon Nanotubes - OSTI GOV

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Last Updated: 04 October 2022

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Dual-pace transient heat conduction in vertically aligned carbon nanotube arrays induced by structure separation

Vertically aligned arrays of carbon nanotubes are popular for a wide variety of macroscopic applications that can exploit individual nanotubes' unique characteristics. The measured voltage change over the sample shows a dual-pace thermal response, which could not be achieved using a single thermal diffusivity heat transfer device. The DTR phenomenon becomes permanent from 295 K to ten K. The nano-scale structure separation induced by increased thermal strain leads to macroscale structure separation, resulting in two parallel heat conduction paths that account for the DTR phenomenon. The area ratio of separated CNTs determined by building a new parallel heat transfer model that takes both the transient and steady-state electrical and thermal response into account. Given that transient thermal response plays a major role in these CNTs arrays' mechanical, optical, and electrical behavior, knowing of the thermal transport in these CNTs arrays is highly relevant, considering the fact that transient thermal reactions have a large effect on their mechanical, optical, and electrical behavior is crucial.

Source link: https://www.osti.gov/biblio/1823311


Application-driven synthesis and characterization of hexagonal boron nitride deposited on metals and carbon nanotubes

We first investigated single-layer h-BN synthesized by CVD on single crystal platinum, comparing these films to h-BN deposited on more commonly used polycrystalline Pt and Cu. Our h-BN film made on single crystal Pt has the lowest surface roughness and highest spatial homogeneity, and the most effective spatial homogeneity, and our electrochemical transfer process allows the Pt to be reused with no visible degradation. We also show that transferred monolayer h-BN can protect MoS2 from damage at high temperatures, as well as other applications that take advantage of the conformal h-BN deposition.

Source link: https://www.osti.gov/biblio/1870017


Tri-molybdenum phosphide (Mo 3 P) and multi-walled carbon nanotube junctions for volatile organic compounds (VOCs) detection

The detection and analysis of volatile organic compounds' biomarkers by volatile organic compounds' biomarkers can lead to improvements in healthcare diagnosis and other areas such as chemical threat detection and food quality control. We're here talking about tri-molybdenum phosphide and multiwalled carbon nanotube junction-based vapor quantum resistive sensors, which have a higher sensitivity and superior selectivity for biomarkers in comparison to pristine MWCNT junctions based on vQRSs.

Source link: https://www.osti.gov/biblio/1865808


Electrostatic gating of ion transport in carbon nanotube porins: A modeling study

Carbon nanotube porins are biomimetic membrane channels with exceptional biocompatibility and unique water and ion transport characteristics. A Gating transport in CNTPs with external voltage could increase control over ion flow and selectivity. Our findings show that the most effective gated CNTP unit is made up of a semiconducting CNTP layer embedded within a small membrane patch containing an internally conductive layer. In addition, we show that gate voltage modulation of ionic transport is controlled by the charge distribution along the CNTP under the external gate electric potential.

Source link: https://www.osti.gov/biblio/1785438


Silver-carbon-nanotube composite metallization for increased durability of silicon solar cells against cell cracks

Solar modules' degradation rate can be reduced and extend their lifetimes beyond 30 years, one of the ways to reduce the cost of solar energy is to minimize solar energy's reduction. After screen-printing and firing, the carbon nanotubes are optimally functionalized and incorporated into commercial silver pastes, resulting metal contacts on solar cells exhibit exceptional fracture toughness. The composite paste has similar beginning-of-life cell results as the standard silver paste, while still delivering crack-tolerant mechanical properties.

Source link: https://www.osti.gov/biblio/1769384


Tuning spin–orbit coupling in (6,5) single-walled carbon nanotube doped with sp 3 defects

A promising class of optoelectronic materials with brilliant photoluminescence and demonstrated single-photon emission is shown by single-photon emission single-walled carbon nanotubes containing sp 3 defects. We investigate the earliest simulated defects of four synthesized and three potential defects on the tube and find that none of the synthesized defects considered introduces a single electron in a localized midgap defect-centered state containing a single electron, u23480. 2. u20130. 3 eV above the valence bandwagon. A measure of excited state transition coupling is demonstrated by spinu2013orbit coupling. We suspect that only the chlorodiphosphorepalladium [Cl 2 Pd] defect resulted in increased spin spinu2013orbit splitting of the defect state and the conduction band associated with the pristine-like SWCNT's spin-u2013orbit coupling of excited state transitions. This report shows that for unpassivated sp 3 defects in SWCNT, a direct bond between a heavy atom and the sp 3 carbon allows for the tuning of spinu2013orbit coupling.

Source link: https://www.osti.gov/biblio/1787300


Engineering efficient bifunctional electrocatalysts for rechargeable zinc–air batteries by confining Fe–Co–Ni nanoalloys in nitrogen-doped carbon nanotube@nanosheet frameworks

We produced Fe-u2013Cou2013Ni trimetallic nanoalloys encapsulated in nitrogen-doped carbon nanotube@nanosheet frameworks for use as effective bifunctional ORR/OER electrocatalysts in this study. Fe2013CoU2013Ni nanoalloys interacting with pyridinic nitrogen-rich carbon synergistically enhanced the adsorption/desorption free energies of oxygen intermediates, thus significantly raising intrinsic ORR/OER performance. FeCoNi-NC exhibits remarkable bifunctionality for the ORR and OER with a 0. 65 percent value, and even surpasses Pt/C/RuO 2 benchmarks.

Source link: https://www.osti.gov/biblio/1767949


Effect of Electrochemical Oxidation on Physicochemical Properties of Fe-Containing Single-Walled Carbon Nanotubes

Metal catalysts are often used to produce carbon nanotubes, but they are often considered impurities in the end products, and lengthy measures are used to remove catalyst residues from the nanotube structure. We investigate Fe-containing single-walled carbon nanotubes' physicochemical characteristics and the effects of simple oxidative pretreatment. We show that a gentle anodic pretreatment i increased the number of oxidized Fe nanoparticles, with most likely showing phases Fe3O4 and Fe2O3, indicating phases Fe3O4 and Fe2O3 and ii, and that ii effectively removed disordered carbonaceous material from SWCNT bundles' surfaces. However, pretreatment could have changed the selectivity of Fe-SWCNTs against paracetamol and morphine, which could be useful.

Source link: https://www.osti.gov/biblio/1769961


Enhanced detection of volatile organic compounds (VOCs) by caffeine modified carbon nanotube junctions

Migrant caffeine migration to the CNTu2013CNT junction has been documented by the localized transmission electron microscopy photograph and energy dispersive X-ray spectroscopy. With a short response time for caffeine-modified CNT junction vs. QRSs, we have obtained more than a order of magnitude higher sensitivity and unique selectivity toward selective VOCs. In addition, the Caf-CNTj sensors that have been produced may be a good candidate to be a part of an electronic nose used for various applications, such as breath measurement and food quality monitoring.

Source link: https://www.osti.gov/biblio/1878337


Water Freezes at Near-Zero Temperatures Using Carbon Nanotube-Based Electrodes under Static Electric Fields

Though static electric fields have been helpful in regulating ice nucleation, the maximum freezing temperature of water that can be achieved in an electric field is also uncertain. We conducted a systematic investigation of the effect of an electric field on water freezing in an electrowetting system in this research by changing the thickness of a dielectric layer and the voltage across it. T f first rises with E, then stabilizes at u20133. 5 %u00b0C after a critical value of 6 u00d7 10 6 V/m.

Source link: https://www.osti.gov/biblio/1769319

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions

* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions