Increased Electrical Conductivity of Carbon Nanotube Fibers by Thermal and Voltage Annealing

We report the effect of annealing, both electrical and by applied voltage, on the electrical conductivity of fibers spun from carbon nanotubes (CNTs). Commercial CNT fibers were used as part of a larger goal to better understand the factors that go into making a better electrical conductor from CNT fibers. A study of thermal annealing in a vacuum up to 800 °C was performed on smaller fiber sections along with a separate analysis of voltage annealing up to 7 VDC; both exhibited a sweet spot in the process as determined by a combination of a two-point probe measurement with a nanoprobe, resonant Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Scaled-up tests were then performed in order to translate these results into bulk samples inside a tube furnace, with similar results that indicate the potential for an optimized method of achieving a better conductor sample made from CNT fibers. The results also help to determine the surface effects that need to be overcome in order to achieve this.

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Enhancing electrical properties of carbon nanotubes thin films by silicon incorporation

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1206/1/012028 ◽

2021 ◽

Vol 1206 (1) ◽

pp. 012028

Author(s):

Sk Faruque Ahmed ◽

Mohibul Khan ◽

Nillohit Mukherjee

Keyword(s):

Thin Films ◽

Carbon Nanotubes ◽

Electrical Conductivity ◽

Photoelectron Spectroscopy ◽

Room Temperature ◽

Chemical Vapor ◽

Binding Energies ◽

Xps Spectra ◽

X Ray ◽

Vapor Deposition Technique

Abstract Silicon incorporated carbon nanotube (Si-CNTs) thin films was prepared by radio frequency plasma enhanced chemical vapor deposition technique. Tetraethyl orthosilicate solution was used for incorporation of silicon in CNTs thin films. Energy dispersive X-ray analysis shows that the silicon atomic percentage was varied from 0 % to 6.1 %. The chemical binding energies of carbon and silicon were analyzed from X-ray photoelectron spectroscopy data. The various peaks at ~531 eV, ~ 285 eV, ~155 eV and ~104 eV was observed in the XPS spectra due to the oxygen, carbon and silicon respectively. Surface morphologies of Si-CNTs thin films have been analyzed by field emission scanning electron microscopy, which revels that the length of the silicon incorporated carbon nanotubes ~500 nm and corresponding diameter ~80 nm. The room temperature electrical conductivity was increased whereas the activation energy was decreased with the increase of atomic percentage of silicon in Si-CNTs thin films. The room temperature electrical conductivity was increased from 4.3 × 103 to 7.1 × 104 S cm−1 as the silicon atomic percentage in Si-CNTs thin films increases from 0 to 6.1 % respectively.

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Comparison of Electronic Structure and Magnetic Properties of Few Layer Graphene and Multiwall Carbon Nanotubes

Advances in Materials Science and Engineering ◽

10.1155/2016/7362131 ◽

2016 ◽

Vol 2016 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Sekhar Chandra Ray

Keyword(s):

Carbon Nanotubes ◽

Raman Spectroscopy ◽

Photoelectron Spectroscopy ◽

Multiwall Carbon Nanotubes ◽

Hysteresis Loops ◽

Structural Defects ◽

X Ray ◽

Layer Graphene ◽

Few Layer Graphene ◽

Multiwall Carbon

A comparative study has been made for the non-catalyst based few layer graphene (FLG) and Fe-catalyst based multiwall carbon nanotubes (MWCNTs). Magnetic and electronic properties of FLG and MWCNTs were studied using magnetic M-H hysteresis loops and synchrotron radiation based X-ray absorption fine structure spectroscopy measurements. Structural defects and electronic and bonding properties of FLG/MWCNTs have been studied using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy (UPS). The work functions of FLG and MWCNTs are 4.01 eV and 3.79 eV, respectively, obtained from UPS (He-I) spectra. UPS (He-II) results suggest that the density of states (DOS) of MWCNTs is higher than FLG and is consistent with Raman spectroscopy result that shows the defect of MWCNTs is higher than FLG. The magnetic coercivity (Hc) of the MWCNTs (~750 Oe) is higher than FLG (~85 Oe) which could be used for various technological magnetic applications.

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Highly active carbon nanotube–promoted Rh-Mn-Li/SiO2 catalysts for the synthesis of C2+ oxygenates from syngas

Journal of Chemical Research ◽

10.1177/1747519820984728 ◽

2021 ◽

pp. 174751982098472

Author(s):

Jun Yu ◽

Ying Han ◽

Guoqing Chen ◽

Xiuzhen Xiao ◽

Haifang Mao ◽

...

Keyword(s):

Carbon Nanotubes ◽

Photoelectron Spectroscopy ◽

Co Hydrogenation ◽

X Ray ◽

Highly Active ◽

Transmission Electron ◽

Co Insertion ◽

Temperature Programmed Surface Reaction ◽

Temperature Programmed ◽

Oxygenate Synthesis

The effect of carbon nanotubes on the catalytic properties of Rh-Mn-Li/SiO2 catalysts was investigated for CO hydrogenation. The catalysts were comprehensively characterized by means of X-ray power diffraction, N2 sorption, transmission electron microscope, H2–temperature-programmed reduction, CO–temperature-programmed desorption, temperature-programmed surface reaction, and X-ray photoelectron spectroscopy. The results showed that an appropriate amount of carbon nanotubes can be attached to the surface of the SiO2 sphere and can improve the Rh dispersion. Moderate Rh-Mn interaction can be obtained by doping with the appropriate amount of carbon nanotubes, which promotes the formation of strongly adsorbed CO and facilitates the progress of CO insertion, resulting in the increase in the selectivity of C2+ oxygenate synthesis.

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Thermoelectric Generator Using Polyaniline-Coated Sb2Se3/β-Cu2Se Flexible Thermoelectric Films

Polymers ◽

10.3390/polym13091518 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1518

Author(s):

Minsu Kim ◽

Dabin Park ◽

Jooheon Kim

Keyword(s):

Electron Microscopy ◽

Electrical Conductivity ◽

Field Emission ◽

Photoelectron Spectroscopy ◽

Thermoelectric Generator ◽

Hydrothermal Reaction ◽

Water Evaporation ◽

Pani Film ◽

Portable Devices ◽

X Ray

Herein, Sb2Se3 and β-Cu2Se nanowires are synthesized via hydrothermal reaction and water evaporation-induced self-assembly methods, respectively. The successful syntheses and morphologies of the Sb2Se3 and β-Cu2Se nanowires are confirmed via X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), and field emission transmission electron microscopy (FE-TEM). Sb2Se3 materials have low electrical conductivity which limits application to the thermoelectric generator. To improve the electrical conductivity of the Sb2Se3 and β-Cu2Se nanowires, polyaniline (PANI) is coated onto the surface and confirmed via Fourier-transform infrared spectroscopy (FT-IR), FE-TEM, and XPS analysis. After coating PANI, the electrical conductivities of Sb2Se3/β-Cu2Se/PANI composites were increased. The thermoelectric performance of the flexible Sb2Se3/β-Cu2Se/PANI films is then measured, and the 70%-Sb2Se3/30%-β-Cu2Se/PANI film is shown to provide the highest power factor of 181.61 μW/m·K2 at 473 K. In addition, a thermoelectric generator consisting of five legs of the 70%-Sb2Se3/30%-β-Cu2Se/PANI film is constructed and shown to provide an open-circuit voltage of 7.9 mV and an output power of 80.1 nW at ΔT = 30 K. This study demonstrates that the combination of inorganic thermoelectric materials and flexible polymers can generate power in wearable or portable devices.

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Detection of sulphur and polysulphides on electrochemically oxidized pyrite surfaces by X-ray photoelectron spectroscopy and Raman spectroscopy

Journal of Electroanalytical Chemistry ◽

10.1016/0022-0728(90)87332-e ◽

1990 ◽

Vol 292 (1-2) ◽

pp. 139-152 ◽

Cited By ~ 177

Author(s):

J.R. Mycroft ◽

G.M. Bancroft ◽

N.S. McIntyre ◽

J.W. Lorimer ◽

I.R. Hill

Keyword(s):

Raman Spectroscopy ◽

Photoelectron Spectroscopy ◽

X Ray

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X-ray photoelectron spectroscopy and Raman spectroscopy investigations of amorphous SixC1x(H) coatings obtained by chemical vapour deposition from thermally labile organosilicon compounds

Thin Solid Films ◽

10.1016/0040-6090(83)90495-9 ◽

1983 ◽

Vol 101 (1) ◽

pp. 83-96 ◽

Cited By ~ 27

Author(s):

J.P. Gerault ◽

R. Morancho ◽

G. Constant ◽

P. Mazerolles ◽

J.J. Ehrhardt ◽

...

Keyword(s):

Raman Spectroscopy ◽

Chemical Vapour Deposition ◽

Photoelectron Spectroscopy ◽

Vapour Deposition ◽

Chemical Vapour ◽

Organosilicon Compounds ◽

X Ray

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Use of anti-solvent to enhance thermoelectric response of hybrid-halide perovskite thin films

Japanese Journal of Applied Physics ◽

10.35848/1347-4065/ac4adb ◽

2022 ◽

Author(s):

Shrikant SAINI ◽

Izuki Matsumoto ◽

Sakura Kishishita ◽

Ajay Kumar Baranwal ◽

Tomohide Yabuki ◽

...

Keyword(s):

Thin Films ◽

Electrical Conductivity ◽

Photoelectron Spectroscopy ◽

High Performance ◽

Cost Effective ◽

Performance Tuning ◽

Charge Carrier Density ◽

X Ray ◽

Thermoelectric Energy Harvesting ◽

Halide Perovskite

Abstract Hybrid halide perovskite has been recently focused on thermoelectric energy harvesting due to the cost-effective fabrication approach and ultra-low thermal conductivity. To achieve high performance, tuning of electrical conductivity is a key parameter that is influenced by grain boundary scattering and charge carrier density. The fabrication process allows tuning these parameters. We report the use of anti-solvent to enhance the thermoelectric performance of lead-free hybrid halide perovskite, CH3NH3SnI3, thin films. Thin films with anti-solvent show higher connectivity in grains and higher Sn+4 oxidation states which results in enhancing the value of electrical conductivity. Thin films were prepared by a cost-effective wet process. Structural and chemical characterizations were performed using x-ray diffraction, scanning electron microscope, and x-ray photoelectron spectroscopy. The value of electrical conductivity and the Seebeck coefficient were measured near room temperature. The high value of power factor (1.55 µW/m.K2 at 320 K) was achieved for thin films treated with anti-solvent.

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Characterization of gold nanoclusters synthesized on carbon nanotubes film: Evaluation of the size distributions by means of X-ray photoelectron spectroscopy

Surface Science ◽

10.1016/j.susc.2009.12.010 ◽

2010 ◽

Vol 604 (5-6) ◽

pp. 508-512 ◽

Cited By ~ 6

Author(s):

L. Minati ◽

S. Torrengo ◽

G. Speranza

Keyword(s):

Carbon Nanotubes ◽

Photoelectron Spectroscopy ◽

Gold Nanoclusters ◽

Size Distributions ◽

X Ray

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Multiwalled Carbon Nanotubes Covered with Cobalt (II) Phthalocyanine by In Situ Synthesis and its Electrochemical Sensing Performance towards DA and UA

Materials Science Forum ◽

10.4028/www.scientific.net/msf.809-810.43 ◽

2014 ◽

Vol 809-810 ◽

pp. 43-52

Author(s):

Hua Hua Wang ◽

Nan Li ◽

Kai Li ◽

Yuan Bu ◽

Wen Le Dai ◽

...

Keyword(s):

Carbon Nanotubes ◽

Multiwalled Carbon Nanotubes ◽

Photoelectron Spectroscopy ◽

Simultaneous Detection ◽

Thick Layer ◽

Electrochemical Sensing ◽

Multiwalled Carbon ◽

X Ray ◽

Platinum Particles

Multiwalled carbon nanotubes (MWCNTs) as an excellent supporter covered with a thick layer of cobalt phthalocyanine (CoPc) were prepared by in-situ synthesis. Platinum particles were adopted to enhance the conductivity of CoPc-MWCNTs. The final nanocomposite Pt-CoPc-MWCNTs was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Strong aromatic π-π stacking between MWCNTs and CoPc made CoPc in-situ forming on MWCNTs. With homogeneous thickness of CoPc covered on the MWCNTs and Pt particles equally distributed, the nanocomposite was used as electrocatalyst. The electrochemical properties of the composite got researched by casting the dispersion of Pt-CoPc-MWCNTs on the glassy carbon electrode. Compared with other modified electrodes, Pt-CoPc-MWCNTs/GC electrode exhibited excellent electrochemical activity towards dopamine (DA) and uric acid (UA). Linear responses for DA and UA were obtained in the ranges of 5 to 170 μM and 5 to 100 μM, and limits of detection were 2.6 and 1.4 μM (S/N= 3), respectively. Simultaneous detection of DA and UA in the presence of ascorbic acid (AA) also displayed selective property, with no interference to each other.

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