scholarly journals Sensing Organophosphorus Compounds with SWCNT Films

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4915
Author(s):  
Mika Sahlman ◽  
Mari Lundström ◽  
Dawid Janas

Promising electrical properties of single-walled carbon nanotubes (SWCNTs) open a spectrum of applications for this material. As the SWCNT electronic characteristics respond well to the presence of various analytes, this makes them highly sensitive sensors. In this contribution, selected organophosphorus compounds were detected by studying their impact on the electronic properties of the nanocarbon network. The goal was to untangle the n-doping mechanism behind the beneficial effect of organic phosphine derivatives on the electrical conductivity of SWCNT networks. The highest sensitivity was obtained in the case of the application of 1,6-Bis(diphenylphoshpino)hexane. Consequently, free-standing SWCNT films experienced a four-fold improvement to the electrical conductivity from 272 ± 21 to 1010 ± 44 S/cm and an order of magnitude increase in the power factor. This was ascribed to the beneficial action of electron-rich phenyl moieties linked with a long alkyl chain, making the dopant interact well with SWCNTs.

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1113 ◽  
Author(s):  
Bogumiła Kumanek ◽  
Tomasz Wasiak ◽  
Grzegorz Stando ◽  
Paweł Stando ◽  
Dariusz Łukowiec ◽  
...  

Despite the widespread use of sonication for individualization of nanomaterials, its destructive nature is rarely acknowledged. In this study, we demonstrated how exposure of the material to a hostile sound wave environment can be limited by the application of another preprocessing step. Single-walled carbon nanotubes (CNTs) were initially ground in a household coffee grinder, which enabled facile deagglomeration thereof. Such a simple approach enabled us to obtain high-quality CNT dispersion at reduced sonication time. Most importantly, electrical conductivity of free-standing films prepared from these dispersion was improved almost fourfold as compared with unground material eventually reaching 1067 ± 34 S/cm. This work presents a new approach as to how electrical properties of nanocarbon ensembles may be enhanced without the application of doping agents, the presence of which is often ephemeral.


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1956
Author(s):  
Monika Rdest ◽  
Dawid Janas

Flexible and conductive materials have a high application potential across many parts of modern life. In this work, thin free-standing films from single-walled carbon nanotubes (SWCNTs) were doped with Ag to enhance their electrical conductivity. A facile method to integrate these two materials is described herein. As a consequence, the material exhibited a six-fold boost to the electrical conductivity: an increase from 250 ± 11 S/cm to 1721 ± 125 S/cm. Interestingly, the specific conductivity remained at a comparable level upon doping, so the material was deemed promising in exploitation fields whereweight is of the essence. Furthermore, the material showed good bending characteristics, thereby revealing its applicability in flexible electronics.


2015 ◽  
Vol 1108 ◽  
pp. 33-38 ◽  
Author(s):  
W.A.D. Wan Dalina ◽  
M. Mariatti ◽  
Soon Huat Tan ◽  
Z.A. Mohd Ishak ◽  
Abdul Rahman Mohamed

Free-standing carbon nanotubes (CNTs) film known as buckypaper is a method used to address dispersion problems of CNTs. Unique properties of CNTs made the CNTs buckypaper to be considered as promising reinforcement materials in development of high-performance of nanocomposites. Buckypaper was fabricated by dispersing multi-walled carbon nanotubes (MWCNTs) in two different types of solution namely Triton X-100 and ethanol then followed by filtration process. In this study, MWCNTs loading and pressure used during filtration process were manipulated. The morphology, thermal and electrical conductivity of the buckypaper produced was studied.


Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 394 ◽  
Author(s):  
Beate Krause ◽  
Viktor Bezugly ◽  
Vyacheslav Khavrus ◽  
Liu Ye ◽  
Gianaurelio Cuniberti ◽  
...  

Composites based on the matrix polymer polypropylene (PP) filled with single-walled carbon nanotubes (SWCNTs) and boron-doped SWCNTs (B-SWCNTs) were prepared by melt-mixing to analyze the influence of boron doping of SWCNTs on the thermoelectric properties of these nanocomposites. It was found that besides a significantly higher Seebeck coefficient of B-SWCNT films and powder packages, the values for B-SWCNT incorporated in PP were higher than those for SWCNTs. Due to the higher electrical conductivity and the higher Seebeck coefficients of B-SWCNTs, the power factor (PF) and the figure of merit (ZT) were also higher for the PP/B-SWCNT composites. The highest value achieved in this study was a Seebeck coefficient of 59.7 µV/K for PP with 0.5 wt% B-SWCNT compared to 47.9 µV/K for SWCNTs at the same filling level. The highest PF was 0.78 µW/(m·K2) for PP with 7.5 wt% B-SWCNT. SWCNT macro- and microdispersions were found to be similar in both composite types, as was the very low electrical percolation threshold between 0.075 and 0.1 wt% SWCNT. At loadings between 0.5 and 2.0 wt%, B-SWCNT-based composites have one order of magnitude higher electrical conductivity than those based on SWCNT. The crystallization behavior of PP is more strongly influenced by B-SWCNTs since their composites have higher crystallization temperatures than composites with SWCNTs at a comparable degree of crystallinity. Boron doping of SWCNTs is therefore a suitable way to improve the electrical and thermoelectric properties of composites.


Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3808 ◽  
Author(s):  
Blazej Podlesny ◽  
Bogumila Kumanek ◽  
Angana Borah ◽  
Ryohei Yamaguchi ◽  
Tomohiro Shiraki ◽  
...  

Single-walled carbon nanotubes (SWCNTs) remain one of the most promising materials of our times. One of the goals is to implement semiconducting and metallic SWCNTs in photonics and microelectronics, respectively. In this work, we demonstrated how such materials could be obtained from the parent material by using the aqueous two-phase extraction method (ATPE) at a large scale. We also developed a dedicated process on how to harvest the SWCNTs from the polymer matrices used to form the biphasic system. The technique is beneficial as it isolates SWCNTs with high purity while simultaneously maintaining their surface intact. To validate the utility of the metallic and semiconducting SWCNTs obtained this way, we transformed them into thin free-standing films and characterized their thermoelectric properties.


Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1150
Author(s):  
Nicolás A. Ulloa-Castillo ◽  
Roberto Hernández-Maya ◽  
Jorge Islas-Urbano ◽  
Oscar Martínez-Romero ◽  
Emmanuel Segura-Cárdenas ◽  
...  

This article focuses on exploring how the electrical conductivity and densification properties of metallic samples made from aluminum (Al) powders reinforced with 0.5 wt % concentration of multi-walled carbon nanotubes (MWCNTs) and consolidated through spark plasma sintering (SPS) process are affected by the carbon nanotubes dispersion and the Al particles morphology. Experimental characterization tests performed by scanning electron microscopy (SEM) and by energy dispersive spectroscopy (EDS) show that the MWCNTs were uniformly ball-milled and dispersed in the Al surface particles, and undesirable phases were not observed in X-ray diffraction measurements. Furthermore, high densification parts and an improvement of about 40% in the electrical conductivity values were confirmed via experimental tests performed on the produced sintered samples. These results elucidate that modifying the powder morphology using the ball-milling technique to bond carbon nanotubes into the Al surface particles aids the ability to obtain highly dense parts with increasing electrical conductivity properties.


Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1875
Author(s):  
Alexander Yu. Gerasimenko ◽  
Artem V. Kuksin ◽  
Yury P. Shaman ◽  
Evgeny P. Kitsyuk ◽  
Yulia O. Fedorova ◽  
...  

A technology for the formation of electrically conductive nanostructures from single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT), and their hybrids with reduced graphene oxide (rGO) on Si substrate has been developed. Under the action of single pulses of laser irradiation, nanowelding of SWCNT and MWCNT nanotubes with graphene sheets was obtained. Dependences of electromagnetic wave absorption by films of short and long nanotubes with subnanometer and nanometer diameters on wavelength are calculated. It was determined from dependences that absorption maxima of various types of nanotubes are in the wavelength region of about 266 nm. It was found that contact between nanotube and graphene was formed in time up to 400 fs. Formation of networks of SWCNT/MWCNT and their hybrids with rGO at threshold energy densities of 0.3/0.5 J/cm2 is shown. With an increase in energy density above the threshold value, formation of amorphous carbon nanoinclusions on the surface of nanotubes was demonstrated. For all films, except the MWCNT film, an increase in defectiveness after laser irradiation was obtained, which is associated with appearance of C–C bonds with neighboring nanotubes or graphene sheets. CNTs played the role of bridges connecting graphene sheets. Laser-synthesized hybrid nanostructures demonstrated the highest hardness compared to pure nanotubes. Maximum hardness (52.7 GPa) was obtained for MWCNT/rGO topology. Regularity of an increase in electrical conductivity of nanostructures after laser irradiation has been established for films made of all nanomaterials. Hybrid structures of nanotubes and graphene sheets have the highest electrical conductivity compared to networks of pure nanotubes. Maximum electrical conductivity was obtained for MWCNT/rGO hybrid structure (~22.6 kS/m). Networks of nanotubes and CNT/rGO hybrids can be used to form strong electrically conductive interconnections in nanoelectronics, as well as to create components for flexible electronics and bioelectronics, including intelligent wearable devices (IWDs).


1994 ◽  
Vol 359 ◽  
Author(s):  
Jun Chen ◽  
Haiyan Zhang ◽  
Baoqiong Chen ◽  
Shaoqi Peng ◽  
Ning Ke ◽  
...  

ABSTRACTWe report here the results of our study on the properties of iodine-doped C60 thin films by IR and optical absorption, X-ray diffraction, and electrical conductivity measurements. The results show that there is no apparent structural change in the iodine-doped samples at room temperature in comparison with that of the undoped films. However, in the electrical conductivity measurements, an increase of more that one order of magnitude in the room temperature conductivity has been observed in the iodine-doped samples. In addition, while the conductivity of the undoped films shows thermally activated temperature dependence, the conductivity of the iodine-doped films was found to be constant over a fairly wide temperature range (from 20°C to 70°C) exhibiting a metallic feature.


RSC Advances ◽  
2016 ◽  
Vol 6 (87) ◽  
pp. 84200-84208 ◽  
Author(s):  
Adil Sultan ◽  
Sharique Ahmad ◽  
Faiz Mohammad

We report the synthesis of polypyrrole (PPy) and polypyrrole/silicon carbide nanocomposites (PPy/SiC) and PPy/SiC/dodecylbenzenesulfonic acid (DBSA) by in situ chemical polymerization and their application as sensors for the detection of highly toxic chlorine gas.


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